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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Suggested Citation:"Chapter 3 - Roadways." National Academies of Sciences, Engineering, and Medicine. 2011. Wayfinding and Signing Guidelines for Airport Terminals and Landside. Washington, DC: The National Academies Press. doi: 10.17226/13640.
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Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

3.1 Wayfinding Philosophy and Principles For specialized destinations like airports, drivers must make multiple decisions in a relatively short span of time and distance. Although airport roadways may have grades, curves, and lane configurations similar to those of a highway, maximum posted speeds on airport roads are typ- ically much lower. Simple and consistent signing throughout an airport’s roadway network is essential to good wayfinding and safe driving. When designing airport wayfinding and signage, the designer and airports are directed to reference the FHWA’s most recent MUTCD for certain engineering design guidelines. Infor- mation regarding letter heights, panel sizes, vehicle speed, line-of-sight readability, highway shields, and symbols is to be referenced and considered. It should be noted, however, that many airports across North America have roadway wayfinding signage systems that currently exist in varying degrees of non-compliance with the MUTCD’s guidelines regarding roadway sign colors, shapes, and fonts. These airports utilize roadway signs that incorporate fonts, col- ors, symbols, and shapes reflective of that airport’s signage system that provide a consistent graphic message throughout the entire airport journey from roadway to parking to curbside to terminal. From a historical perspective earlier versions of the MUTCD were not explicit that the provi- sions of the Manual applied to airports and other private roads, though this expectation was implicit in earlier language concerning authority to install traffic control devices. In a 2004 inter- pretation, subsequently incorporated into the 2009 MUTCD, airport roadways are clearly included as “private roads open to public travel” and thus are subject to the MUTCD provisions. Due to the ambiguity in the past concerning the need to comply with the MUTCD and the dif- ficulty in designing systems that comply fully with the Manual’s standards and guidance, many existing airport signing systems do not conform with the Manual. The challenge for both airport management and the roadway sign design professional is to find a common ground that can satisfy both viewpoints under the current MUTCD guidelines. These differing viewpoints may be summarized as follows: Airport Management Viewpoint Regarding Roadway Signs: • Airport signs are an identity or branding of the airport (i.e., use of similar color and style of signs throughout), providing a sense of arrival and the beginning of the airport user’s experience. • Airport signs should look different than freeway signs, as a means to slow down traffic and confirm entry into a different environment and essentially to say “pay attention—you have arrived at the airport.” 29 C H A P T E R 3 Roadways

Roadway Sign Design Professional Viewpoint: • Airport signs should comply with all traffic signage regulations and design criteria, including the Manual on Uniform Traffic Control Devices (MUTCD). • The more an airport road can be made to look and function like a regular road, the more it will conform to driver expectations which will lead to a safer and less frustrating driving experience. The basic criteria for an effective wayfinding system include the thorough programming of all aspects of vehicular and pedestrian traffic flow, and the appropriate delivery of all pertinent infor- mation to the traveler, visitor, or employee. Given the dichotomy between real world application and the MUTCD guidelines, and the fact that the MUTCD does not currently have a section to address the specific needs of airports, this chapter identifies methods and strategies for develop- ing a roadway wayfinding system that is compliant with the MUTCD. This chapter also addresses the meaning of the terms “engineering judgment” and “request for experimentation” and their relevance for airport roadway design (see Section 3.2.2—Airport Roadways and the MUTCD). Important Note: The MUTCD contains very specific terminology and direction for its proper use. Designers who use the MUTCD are required to understand and apply that direction appro- priately. Since this ACRP document is not the MUTCD and only references non-specific con- tent and use, it is not necessary to use the same strict level of terminology and language that exists in the MUTCD itself. For any reference to the MUTCD contained within this ACRP document, the various terms used (i.e., standards, guidance, guidelines, options, requirements, and recom- mendations) are not intended to be strictly interpreted as if they are used in the MUTCD. As stated previously, the designer should understand and apply the full meaning and intent of all specific terms of use when applying the MUTCD in the sign design process. 3.1.1 Considering User Requirements and Limitations (Human Factors) Drivers entering an airport roadway system bring with them all of their experience and expec- tations about roadway design and traffic control. This experience is gained by driving on con- ventional roads and highways. The more an airport road can be made to look and function like a regular road, the more it will conform to driver expectations which will lead to a safer and less frustrating driving experience. That said, many legacy airport complexes have been planned and developed in a manner that has resulted in unusual and unorthodox roadway layout and designs when compared to typical roadway systems. As a group, in general, airport roadway users often have unique characteris- tics due to their unfamiliarity with the roadway system and integrated facilities, coupled with potentially high levels of driver stress caused by tight flight schedules, security warnings, and other factors. Finally, because airport roadway systems transition downward in speed as they ter- minate in high-density parking terminal environments, this creates difficult combinations of vehicular and pedestrian signing. All of these factors require airport roadway sign designers to utilize all of their skills to plan and design the most safe and efficient guidance and information signing system for both vehicles and pedestrians. It is important to remember that roadway signs for vehicular drivers should be considered fundamentally different than interior and, to some degree, even parking facility signs. The users of roadway signs are in vehicles moving at much higher speeds, and their attention should pri- marily be directed toward the safe operation of their vehicle, including their interaction with pedestrians, such as in terminal curbside areas. Drivers will more easily and safely navigate when they can rely on their previous experience with roadway signs. By making airport roadway signs look, feel and operate like other roadway signs, the needs of the driver are better served. The prin- ciple of uniformity as promoted in the MUTCD does not end at the airport property line. 30 Wayfinding and Signing Guidelines for Airport Terminals and Landside

As previously noted, the MUTCD does not have a separate chapter or section on airports. Never- theless, until that time when such a section exists, the principles of the MUTCD can and should be applied to airport roadway signing using sound engineering judgment. Section 1A.02 of the MUTCD lays out key principles of all traffic control devices, which include signs, marking, signals, and related devices. This section provides guidance that states: To be effective, a traffic control device should meet five basic requirements: A. Fulfill a need; B. Command attention; C. Convey a clear, simple meaning; D. Command respect from road users, and; E. Give adequate time for proper response. This section further lists five aspects that should be considered in order to ensure that a traf- fic control device meets these requirements: 1. Design 2. Placement 3. Operation (for signals and changeable message signs) 4. Maintenance 5. Uniformity One of the main challenges facing an engineer when designing traffic control device layouts for roadways at legacy airports is how many decision points should there be and how close should they be spaced combined with unusual roadway geometrics. It is important to remember that traffic control devices (including signs) are not necessarily the best remedy for all traffic opera- tions needs. Signing and pavement markings cannot correct fundamentally poor or unusual roadway, intersection, and ramp design. Good communication with drivers begins with good roadway design that conforms to their expectations. Traffic engineers may need to conduct an engineering study of roadway, intersection, and ramp design to discover if changes to the geo- metric design of the road to better conform to driver expectations offer a better solution than a traffic control device. In many legacy airport situations the geometric design may not be able to be altered. The MUTCD acknowledges this close connection between roadway design and traf- fic control devices in Section 1A.09, which states: Early in the processes of location and design of roads and streets, engineers should coordinate such loca- tion and design with the design and placement of the traffic control devices to be used with such roads and streets. Traffic safety engineering often talks of the design driver—a hypothetical person for whom the roadway is tailored. In order to provide a margin of safety, the design driver is typically assumed to be unfamiliar with the area and driving under less than ideal conditions—such as at night or in the rain. In an airport situation, this design driver could also be assumed to be pressed for time and mentally distracted due to travel concerns and unfamiliar surroundings. All of these factors lead to designs which assume the driver needs longer than average response and reading times to process signs and roadway elements. It is often hard for designers to put themselves in the role of the unfamiliar driver, but it is essential for good signing decisions. Section 1A.02 of the MUTCD also stresses that “vehicle speed must be carefully considered as an element that governs the design, operation, placement, and location of various traffic control devices.” Drivers need time to process the information present on road signs, building signs, and curbside signs. If the roadway design does not provide adequate distance, a speed reduction on the roadway is one way to provide drivers more time to process the information. Any changes to posted speed limits should be accompanied by adequate roadway and roadside design along with speed enforcement to accomplish the desired behavioral change. Roadways 31

Close placement of signs, excessive sign messaging and subsequent information overload, is a concern at airports due to the closely spaced access points to many destinations such as multi- ple terminals, multiple parking facilities, rental car facilities, curbside loading/unloading and var- ious other airport services. The need to provide signs for each of these areas leads to shorter sign spacing and more sign information than is generally recommended in most roadway sign stan- dards and guidance documents. It is important to remember that people react in time but stan- dards are written in distance. The standards for sign spacing and letter height are included in this section. If adequate distance can’t be provided due to site and roadway characteristics, then road- way speeds should be lowered if possible to provide adequate time for drivers to respond, or let- ter heights should be larger, or both. It should be noted that reducing driver speed, especially at the entrance to the airport where they may be transitioning from a typical freeway or arterial environment, requires road design changes to support the requested reduction in speed. A change in the posted speed alone is typically ineffective. Altering roadway and roadside design, along with speed management techniques and law enforcement of posted speeds, may also be crucial for compliance. Drivers’ visual and cognitive abilities vary greatly and these affect how easily a sign can be read and understood. Vehicle and headlamp design also affect sign visibility, as does the curva- ture of the roadway and any horizontal or vertical elements within or adjacent to the roadway. The legibility standards established in the MUTCD are based on extensive research into all of these areas. To summarize, design professionals and airports should always start with the MUTCD and its principles when designing and applying traffic control devices in the airport environment. Only after those principles and guidance have been exhausted should they consider an alternate traf- fic control device design or placement. The MUTCD should always be the point from where air- port sign designers begin their design, and any deviations should be noted and justified in writing during the design process. The guidelines developed for this section are primarily based on the MUTCD and other research and standards for general roadway signing. Readers should always consult the original source documents for the details of implementation. 3.1.2 Positive Guidance In order for users to have a comfortable and efficient wayfinding experience through an airport roadway system, they need positive guidance. In other words, guide drivers by clearly laying out the proper path. Although the concept of positive guidance was developed within the areas of traffic engineer- ing and highway design, its principles apply equally to the curbside, terminal and parking lots. Knowledge of human limitations in information processing, and human reliance on previous experience to compensate for this limitation, led to the positive guidance approach to highway design. This approach is based on a combination of human factors and traffic engineering, which was developed in the early 1970s by Alexander and Lunenfeld and elaborated on in a series of doc- uments published by the U.S. Department of Transportation Federal Highway Administration6. The central tenet of the positive guidance approach is that design according to driver limita- tions and expectations increases the likelihood of drivers responding to situations and informa- tion correctly and quickly. Conversely, when drivers are not provided with information in a timely fashion or are overloaded with information, or are surprised because their expectations are vio- lated, slowed responses and errors occur. 32 Wayfinding and Signing Guidelines for Airport Terminals and Landside

With respect to road design, the positive guidance approach emphasizes: • Expectation—Design roadway configurations and geometrics and traffic operations in accor- dance with driver expectations. Design should conform to long-term expectancies (e.g., there are no traffic signals on freeways, freeway exits are on the right) as well as short-term expectan- cies (e.g., all curves on this road are gradual). With respect to traffic control devices, the positive guidance approach emphasizes the following: • Primacy—Determine the placement of signs according to the importance of their informa- tion (e.g., stop signs are more important than parking payment signs, or in an airport envi- ronment, terminals are more important than cargo areas), and in such a way as to avoid presenting the driver with information when and where it is not essential. • Spreading—Where all the information required by the driver cannot be placed on one sign or on a number of signs at one location, spread it out along the road so that information is given in small chunks, thereby reducing the information load on the driver. • Coding—Where possible, organize pieces of information into larger units. Color and shape coding of traffic signs accomplish this by representing specific information about the message based on the color of the sign background and the shape of the sign panel (e.g., warning signs are yellow and typically diamond shaped). • Repetition—Say the same thing in more than one way (e.g., shape, color). The same infor- mation may also be given with two different devices (e.g., “no passing” indicated with a sign and pavement markings), or by two identical devices (e.g., STOP signs on both sides of a wide intersection). 3.2 Applicable Federal Standards The Federal Highway Administration (FHWA) oversees the standards and practices for traffic signs, signals, and markings. They produce the MUTCD under 23 Code of Federal Regulations (CFR), Part 655, Subpart F. The MUTCD defines the standards used by road managers nation- wide to install and maintain traffic control devices on all public streets, highways, bikeways, and private roads open to public traffic. The MUTCD approved by the Federal Highway Administration is the national standard for all traffic control devices installed on any street, highway, or bicycle trail open to public travel. For the purpose of MUTCD applicability, open to public travel includes toll roads and roads within shopping centers, airports, sports arenas, and other similar business and/or recreation facilities that are privately owned but where the public is allowed to travel without access restrictions54. Each state must adopt the Federal MUTCD or a state-specific alternative manual or supplemen- tal material that is in substantial conformance to the National manual. The recommendations in this document refer to the 2009 Edition of the MUTCD. 3.2.1 MUTCD Organization and Terms Before addressing MUTCD applicability in airport roadway systems, it is important to under- stand how the MUTCD is organized and terminology used. For many sign applications, the MUTCD distinguishes between “Freeways and Expressways” and “Conventional Roads.” The main thing that distinguishes these two road classes from each other is operating speed and the presence of driveways and intersections. For most situations, airport roads (including terminal curbside roads) would be considered “Conventional Roads” because they typically have operating speeds lower than 45 mph, and they have frequent drive- Roadways 33

ways and at-grade intersections and may have pedestrian activity along and/or across them. Air- ports may also own and operate freeway or expressway-type roadways with limited or partially controlled access and operating speeds higher than 45mph. In those cases, the sign designer should consider use of the principles and guidance in the “Freeways and Expressways” section of the Manual to address the likely higher speeds, volumes and entrance/exit ramp conditions. The MUTCD refers to signs by their function or class, such as regulatory, warning and guide signs. Each sign class is addressed in a separate chapter of the Manual. In addition, there are addi- tional chapters dedicated to school areas, highway-rail crossings, bicycle facilities, and light-rail transit grade crossings which are less likely to be used by airports. Throughout the MUTCD, the headings Standard, Guidance, Option, and Support are used to classify the nature of the text that follows. Designers should understand and pay close attention to these definitions and requirements as listed in the MUTCD and defined as the following: • Standard—a statement of required, mandatory, or specifically prohibitive practice regarding a traffic control device. Standard statements are sometimes modified by options. Standard statements shall not be modified or compromised based on engineering judgment or engineer- ing study. • Guidance—a statement of recommended, but not mandatory, practice in typical situations, with deviations allowed if engineering judgment or engineering study indicates the deviation to be appropriate. Guidance statements are sometimes modified by options. • Option—a statement of practice that is a permissive condition. • Support—an informational statement which provides background and rationale for a stan- dard, guidance, or option statement. 3.2.2 Airport Roadways and the MUTCD The MUTCD contains little guidance on how to apply MUTCD principles and standards to airport roadways as a unique category although it does specifically state that airport roads open to public travel shall comply with the MUTCD. This lack of detailed guidance does not, how- ever, give airport sign designers and operators permission to avoid compliance with these road- way signing standards. Airports should retain the services of licensed professional engineers who are experienced in roadway design, including roadway signing design, and are therefore able to exercise engineering judgment for particular site and traffic flow characteristics. In Section 1A.09 of the MUTCD, the Manual addresses the issue of engineering judgment by stating as a Standard Statement, “This Manual describes the application of traffic control devices, but shall not be a legal requirement for their installation.” It provides further guidance which states that engineering judgment should be exercised in the selection and application of traffic control devices. Engineering judgment does not mean, in this context, that substitution of alter- native devices can take place at will. The formal request for experimentation process, including the evaluation, described herein should be followed. The MUTCD does allow some flexibility in interpretation through engineering judgment and study. It is important to note, however, that the Manual clearly states any Standard statement cannot be ignored or overruled by engineering judgment. Only Guidance and Option statements can be interpreted through engineering judgment (see Section 1A.13, definition of a Standard; also reference Official Ruling No. 1(09)–1(I) issued October 1, 2010). FHWA has made provision for agencies to request interpretations of MUTCD language to par- ticular situations. An agency can also request experimentation with a new traffic control device or application of an existing device to a new situation. Experimentations require a formal evaluation of the device to demonstrate that the new device provides an improvement over the current stan- 34 Wayfinding and Signing Guidelines for Airport Terminals and Landside

dard. The process for these types of requests is detailed in Section 1A.10 of the MUTCD. A library of past interpretations and current experimentations is maintained by FHWA at their website7,8. A listing of additional related resources is available in Appendix E. 3.3 Airport Roadway Decision Points Airport roadways present a unique challenge for motorists, especially for infrequent travelers or those making their first trip to the airport. Motorists are faced with several decision points in close proximity to one another as they transition from adjacent freeways to the airport. These decision points may include the following: • Exit ramp from freeway, • Airline name/terminal listing, • Split between roads leading to each terminal, • Split between arrivals and departures, • Split between curbside, parking and car rental, • Split between short term and long term parking, and • Return to terminal or exit airport property. In order for a driver to navigate to the intended destination safely, signs need to be conspicuous, legible, brief, understandable, and located a sufficient distance from the choice point (and each other) to allow enough time to detect, read, make a decision, and make the necessary lane changes. An airport operator should analyze the roadway system in order to identify these decision points. One way to do this is to create a matrix of likely trip purposes as shown in Figure 3.1 Roadways 35 Roadway Name Type of User User Familiarity Trip Purpose Trip Origin Trip Destination Information Needs Wright Blvd. Departing Passenger (local resident) Familiar Park in Garage Main Entrance Garage Which terminal is my airline? What are the parking options? Where is the entrance to parking? Departing Passenger (non- resident) Unfamiliar Return Rental Car Main Entrance Rental Area Where is the rental return? Where is the entrance to return? Where is my specific car agency? Taxi Familiar Pick-up Re-Entry Road Arrivals Curbside Detours/Incidents Service Road Postal patron Familiar Drop off mail Wright Blvd. Post Office Where is the Post Office? How do I get there? Employee Familiar Work Wright Blvd. Employee Parking Detours/Incidents Airfield Dr. Truck driver Unfamiliar Food delivery Main Entrance Loading Dock Where is the delivery area? How do I get there? Are there height and weight restrictions? Personal Vehicle Familiar Pick-up Passenger Main Entrance Cell Phone Waiting Area Is there a waiting area? How do I get there? Figure 3.1. Example of trip purpose and travel path analysis.

(adapted from Hawkins, et al.9). Note that one roadway could be serving drivers with differing trip purposes and information needs. This table is for illustrative purposes only; each airport should consider its many users and paths through its facilities. The Mineta San Jose International Airport is one example of a facility which has conducted a thorough circulation analysis for both motorists and bicyclists10. Overlaid on this roadway dia- gram are circles indicating decision point locations at intersections and ramps (Figure 3.2). These circles, then, serve to flag areas where advance directional signing is needed. 3.3.1 Airport Exit Signs Signs leading drivers out of the airport are as important as those leading drivers in. As drivers exit the airport, decision points include the splits between remaining within the airport and exit- ing the airport from the terminal to major freeways or destinations (e.g., city downtown). Con- formance to the MUTCD is important as these signs begin to prepare drivers to enter state and local roads. The use of standard route markers and sign colors is especially important. Local jar- gon terms for routes should be avoided in favor of highway numbers that would appear on road- way maps. Key destinations, such as “Downtown” of “TO <Major Highway>,” should be listed on exit signs, particularly in advance of lane splits (see Figure 3.3). On a national level, control 36 Wayfinding and Signing Guidelines for Airport Terminals and Landside Figure 3.2. Example decision point and circulation flow diagram from the Mineta San Jose International Airport. Figure 3.3. MUTCD route numbers used on signs at DFW.

destinations should conform with the AASHTO list of control cities and/or official control des- tinations as determined by the State DOT for the region (AASHTO Guide Signs, Part III: List of Control Cities for Use in Guide Signs on Interstate Highways)11. 3.4 Static Sign Design Elements 3.4.1 Terminology The terminology used for airport roadway signing should be straightforward. The roadway signing terminology should be reviewed as part of the overall airport passenger experience, (parking, curbside, and terminal), to ensure all terminology conveys a cohesive and consistent message. A basic premise for guide sign messaging is to use as few words as possible. The reason is reader comprehension that is dependent on rate of travel, viewing distance, and length of message. These factors such as the length of the message (Departures as compared to Ticketing/Check-In) also impact driver safety. The following are key terminology: • Terminal—is required if there is more than one terminal or if the one terminal has a split curbside (e.g., North/South). If there is more than one terminal the messaging will require a unique designation for each terminal. Simple designations such as 1, 2, 3 or A, B, C work best for roadway applications. (See Figure 3.6) • Arrivals/Departures—used to identify the curbside areas for passenger drop-off and passen- ger pick-up at the terminal. • Parking—used to identify parking at the airport. Most airports have multiple parking prod- ucts that can include Hourly, Daily, Economy, Cell Phone Lot, and Valet parking. The specific terminology used to differentiate the various parking products should be part of an overall parking strategy. (Reference Section 4.3 for additional information associated with the signing and naming of parking products.) • Return to Terminal and Airport Exit—these terms are typically used to direct traffic after the motorist has passed the terminal and must decide whether they need to go back to the termi- nal or exit the airport. • Airline listings—Airline information is typically not posted for a single terminal with one common curbside. This information is typically posted at an airport with multiple terminals or a split curbside serving a single terminal. • Rental Cars—Used to identify rental car facilities that include rental car pick-up by area res- idents and rental car returns, in addition to rental car use by arriving passengers. Within the facility area, separate signage for Rental Car Return and Rental Car Lobby should be provided. • Internet Addresses and Phone Numbers—Some airport operators may wish to place phone numbers or Internet address information on roadway signs directing drivers to call for park- ing or terminal information. This practice is expressly forbidden by the MUTCD out of safety concerns. The mental effort required to read and remember web addresses is more than for typical traffic sign words. These materials are permitted in an option statement for locations that are low speed “where an area is available for drivers to stop out of the traffic flow to read the message” (MUTCD Section 2A.06, paragraph 16) or for signs designed to be viewed only by pedestrians or occupants of parked vehicles. 3.4.1.1 Lines of Text and Message Hierarchy The number of lines of text on roadway signs needs to be limited to prevent drivers from tak- ing their eyes off the road for too long. The MUTCD stops short of issuing a standard on the maximum number of lines of text but does offer a Guidance statement in Section 2D.07 that recommends limiting signs to three lines of text. Roadways 37

This is a Guidance statement, which is a recommended practice and is subject to modifica- tion by engineering judgment or study. For signs that list airlines and terminal assignment, many airports list more than three airlines on a single guide sign. If this practice is adopted, it is important to: • List the airlines alphabetically and spread out the list as much as possible to avoid information overload. If necessary, use multiple signs. • Provide adequate letter size for easy and quick legibility of all names listed before the sign is passed at the operating speed (assume approximately 1⁄2 to 1 second reading time per major word or name and legibility of 30 ft per inch of letter height). • Provide good letter-to-background color contrast for easy reading. • Provide adequate space (see next section regarding spacing rules) between successive signs to provide mental processing of the information provided. • Repeat the signs to the extent possible. A uniform hierarchy of messages and information should also be developed. This permits a consistent sign system that considers location of the message on the sign (which line on the sign), and where the message resides (overhead sign or roadside sign). Messages should be categorized as primary or secondary. Primary messages include Terminal, Parking, Rental Cars, Airport Exit, Return to Terminal, and major access roads. Primary messages would most likely be placed on an overhead sign. Placement of primary messages takes priority over secondary messages. Secondary messages include Departures, Arrivals, Terminal designations, airline names for each terminal, and specific parking destinations. Secondary messages supplement or reinforce information already conveyed by the primary messages. Secondary messages may also be on the overhead sign, or considered for placement as a roadside sign. 3.4.2 Symbology The MUTCD makes a distinction between symbols and pictographs. A symbol can stand alone as a substitute for text on a sign while a pictograph is an illustration that is supplemented by text on a sign. According to the MUTCD a “symbol” is defined as, “the approved design of a pictorial repre- sentation of a specific traffic control message for signs, pavement markings, traffic control signals, or other traffic control devices, as shown in the MUTCD.” Designs of pictorial representations that have not been approved are not appropriately termed “symbols.” Based on the airport sur- veys, the majority of airports currently use the following pictorial representations on roadway guide signs that are not adopted in the MUTCD: • Arrivals—plane descending • Departures—plane ascending • Parking—“P” • Rental cars—RC symbol Terminal identifiers, i.e., A B C or 1 2 3 as noted in Figure 3.6 are approved by the MUTCD and serve as important symbols at airport facilities with multiple terminals and/or parking products. The 2009 Airport sign survey indicated that 22% of the airports surveyed included parking, arrivals (plane descending), departing (plane ascending) and rental car symbols. Another 30% had other symbols on their roadway signs such as parking “P” alone, terminal identifiers (A B C or 1 2 3), rental car symbol alone, or hotel symbols. 38 Wayfinding and Signing Guidelines for Airport Terminals and Landside

It should be noted that the symbols for Arrivals, Departures, and Rental Cars are not listed as acceptable symbols in the MUTCD since they have not undergone testing for legibility and com- prehension. These should be treated as pictographs with accompanying explanatory text. Rental Car symbols were studied in a 2008 FHWA project which tested three alternatives for rental car symbols and found that none of them performed acceptably in either comprehension or legibility. Another study also found the current rental car symbol (car with a key above it) to be poorly understood, even though the majority of study participants had rented vehicles. No better alternative symbol has yet been found, suggesting that including the text “Rental Cars” may assist drivers. The MUTCD recommends the use of trailblazer signs on major roads leading to the airport property, featuring the airport symbol. The MUTCD states the following: • Guide signs for commercial service airports and non-carrier airports may be provided from the nearest Interstate, other freeway, or conventional highway intersection directly to the airport, normally not to exceed 15 miles. • The Airport (I-5) symbol sign along with a supplemental plaque may be used to indicate the specific name of the airport. • An Airport symbol sign, with or without a supplemental name plaque or the word AIRPORT, and an arrow may be used as a trailblazer. In an Interpretation Letter FHWA has authorized users to rotate the symbol so that the air- plane is “pointing” at the airport to provide additional cues to drivers, particularly at decision points like intersections. The rotation of the airport symbol does not replace the directional arrow sign installed below the airport symbol sign. In any orientation, the airport symbol should always be accompanied by a standard directional arrow plaque12. 3.4.3 Typography The fonts (also referred to as typefaces or lettering styles) allowed for use on roadway signing are limited to those listed in the MUTCD which are the FHWA Standard Alphabets. In 2004, a more recently developed font, Clearview ™ Highway, was allowed for optional use. The most typically used FHWA Standard Alphabet lettering style for guide signs that has an upper and lower case letter set is called E-modified. A related font that has narrower, more condensed letterforms called Series D is used for guide signs on conventional roads. Legibility research has shown that drivers can read high performance retroreflective sheeting signs with the Clearview™ typeface 10–12% further away than FHWA Standard Alphabet E-modified for non- illuminated signs at night. The difference between the two fonts was less for signs made with less bright retroreflective materials, such as engineering grade, and was also less during the day. The Clearview™ font is used by several airports, including Dallas/Fort Worth as shown in Figure 3.3. The use of Clearview™ is the subject of an Interim Approval by FHWA, and its use must be approved by FHWA. It should be noted that typical airport roadway geometry would not necessarily afford the longer tangent distances in which an increase in nighttime legibility would be realized for non- illuminated signs as a result of using the Clearview™ font. The MUTCD recommends using the legibility index of 30 feet of legibility for every inch of letter height for static signs. This translates to, for example, a legibility distance of 180 feet for a 6 inch letter. This recommendation is based on several research projects which studied nighttime sign legibility with older drivers. In this regard, it is a conservative number for most roadway situations. Because of the complexity of the airport roadway environment and the density of Roadways 39

information, large letter sizes are encouraged. If smaller letter sizes are used, fewer lines of text should be used and the sign should be repeated whenever possible. The MUTCD explicitly bans any letter on guide signs smaller than 6 inches, except roads with speed limits less than 25 mph. A letter size of 6 inches applies to the upper case letter, for which the corresponding lower case letter height is 4.5 inches. In general, mixed case (initial letter upper case, subsequent letters lower case) is required over all upper case letters for destinations dis- played on roadways signs. Tables 2E-1 through 2E-5 of the MUTCD contain the minimum let- ter and numeral sizes for roadway static signs by sign type and roadway speed. These tables bring up an important point. Signs should be designed for actual operating speeds that are unlikely to be the posted speed limit. The one inch per 30 foot legibility index corresponds with the 20/40 visual acuity, which is the typical licensing requirement of most motor vehicle agencies without the use of corrective lenses and is conservative for most roadway situations. Letter sizes for changeable message signs are addressed later in this guide. Typefaces selected for use on interior signing should not be used on roadway signs unless a legibility study of roadway signs has been conducted and a request for experimentation has been filed with FHWA. 3.4.4 Arrows Directional arrow designs are specified in the MUTCD and accompanying Standard Highway Signs manual which specifies dimensions. Examples of MUTCD standard arrows are shown in Figure 3.4. The MUTCD does provide for the option of alternative arrows on airport wayfinding signs provided that a legibility study is conducted and a request for experimentation has been filed with FHWA. See Figure 3.5 for examples of arrows evaluated as part of a National Park Ser- vice (NPS) legibility study (see also Section 6.5.4 for additional background on the NPS study). The arrow ultimately recommended for use on NPS guide signs, Color Detour 1, performed 18% better than the Federal Highway Administration “Standard Arrow” (M6-3). It should be noted that these arrows have not been approved for use by FHWA. A request for experimen- tation must be filed along with an evaluation plan if an airport wishes to try these arrow designs. 40 Wayfinding and Signing Guidelines for Airport Terminals and Landside Figure 3.4. Typical arrow shapes from MUTCD figure 2D-2.

The MUTCD provides guidance for the orientation of arrows on overhead signs in Section 2D. Guidance that particularly pertains to airport roadway wayfinding includes: • On overhead signs where it is desirable to indicate a lane to be followed: – A down arrow shall be positioned approximately over the center of the lane and shall point vertically downward toward the approximate center of that lane. – Down arrows shall be used only on overhead guide signs that restrict the use of specific lanes to traffic bound for the destination(s) and/or route(s) indicated by these arrows. – Down arrows shall not be used unless an arrow can be located over and pointed to the approx- imate center of each lane that can be used to reach the destination displayed on the sign. – If down arrows are used, having more than one down arrow pointing to the same lane on a single overhead sign (or on multiple signs on the same overhead sign structure) shall not be permitted. – Where a roadway is leaving the through lanes, a directional arrow shall point upward at an angle that approximates the alignment of the exit roadway. • Arrows used on guide signs to indicate the directions toward designated routes or destinations should be pointed at the appropriate angle to clearly convey the direction to be taken. A hor- izontally oriented directional arrow design should be used at right-angle intersections. Arrow size should be between 1.5 and 1.75 times the height of the upper-case letters of the principal legend on the sign. For dedicated traffic lanes that serve one destination or ramp exclusively, also called “lane drops,” special signing is needed. One study found that the addition of a black-on-yellow THIS LANE ONLY plaque at the bottom of the airport guide sign, below the MUTCD standard down- arrow, reduced last minute lane changes. THIS LANE ONLY is not a conventional sign legend. The legend ONLY with a down arrow all in a black-on-yellow panel reduces the units of infor- mation and should adequately convey the same message. Supplementary messages such as this, as well as EXIT ONLY, are allowed in the MUTCD and are recommended for lane drop condi- tions. The preferred installation for lane assignment on overhead signs is the word ONLY with a down arrow all within a black-on-yellow panel at the bottom of an overhead sign. See MUTCD Section 2E.24 for additional guidance. Roadways 41 Winged Delta FHWA Down (6-3) FHWA Standard (M6-3) FHWA (6-49) Chevron Color Detour II Montreal Expo Serif Rounded Crow’s Foot Color Detour I Traffic Signal Head FHWA Down (with extended Shaft) Source: National Park Service & Pennsylvania Transportation Institute. Figure 3.5. Arrow shapes used in the NPS arrow study.

Exits to the left are counter to drivers’ expectations and should be specially marked. This includes parking garage entrances and other exit ramps to the left. MUTCD Section 2E.31 provides guid- ance on the design and placement of left exit plaques for guide signs. 3.4.5 Color and Shape The color and shape of a sign helps drivers pick it out from the visual scene. If a driver is actively seeking guidance information, for example, past experience dictates that this will be found on a horizontally rectangular sign, most likely green or blue background. So, in a quick visual scan of a scene, a yellow diamond-shaped sign would likely not register with the driver because he or she is consciously seeking navigational information that is presented in a guide sign format. Consistency in the color and shape of signs on all roadways is important to help drivers quickly read the sign messages. Sign borders of contrasting colors help drivers identify the shape of sign and quickly notice a sign in a cluttered environment. The MUTCD requires the use of borders that are the same color as the legend on all roadway signs. Section 2A.06 contains design details for the borders. Color coding is often used by airports to aid in wayfinding. Unfortunately, many color cod- ing schemes violate standards specified in the MUTCD. There are provisions for using uniquely colored boxes within a traditional green guide sign as shown in Figure 3.6. The accompanying standard language from the MUTCD explains their use: • Support—Color coding is sometimes used to help road users distinguish between multiple potentially confusing destinations. Examples of valuable uses of color coding include guide signs for roadways approaching or inside an airport property with multiple terminals serving multiple airlines, and wayfinding signs for various traffic generator destinations within a community or area. • Standard—Different color sign backgrounds shall not be used to provide color coding of destinations. The color coding shall be accomplished by the use of different colored square or rectangular panels on the face of the guide signs (see Figure 3.6). The 2009 MUTCD identifies the 11 colors in current use and the 2 colors reserved for future use: Both airports and roadways sign design professionals should be aware that the general mean- ing of the 13 colors shall be as follows: • Black—regulation. • Blue—road user services guidance, tourist information, and evacuation route. • Brown—recreational and cultural interest area guidance. • Coral—unassigned. • Fluorescent Pink—incident management. • Fluorescent Yellow-Green—pedestrian warning, bicycle warning, playground warning, school bus and school warning. 42 Wayfinding and Signing Guidelines for Airport Terminals and Landside Figure 3.6. Color coding example from the 2009 MUTCD Figure 2D-1.

• Green—indicated movements permitted direction guidance. • Light Blue—unassigned. • Orange—temporary traffic control. • Purple—lanes restricted to use only by vehicles with registered electronic toll collection (ETC) accounts. • Red—stop or prohibition. • White—regulation. • Yellow—warning. The provision to use colored boxes on wayfinding signs allows for the use of the assigned colors in a wayfinding system. This means that terminal or parking color coding used for interior signing can be carried through to roadway signing through the use of these colored panels on standard green guide signs. As noted at the beginning of this chapter, sign background color is currently a major source of discrepancy. Many airports use colors other than the MUTCD accepted standard green. Based on this standard airports considering alternative background colors should conduct a legibility study and file a request for experimentation with the FHWA. Shape provides an additional cue to motorists as to the category of sign. The MUTCD provides for the applications of sign shapes in Figure 3.7. 3.4.6 Wayfinding Sign Placement, Spacing, and Design Speeds Motorists’ visual and cognitive abilities vary greatly and these affect how easily a sign can be read and understood. Once a driver reads a sign, he or she must have time to cognitively process the information, decide if a maneuver is required, and execute that maneuver. These steps are illustrated in Figure 3.8. Section 1A.02 of the MUTCD stresses that “vehicle speed must be carefully considered as an ele- ment that governs the design, operation, placement, and location of various traffic control devices.” Drivers need time to process the information present on road signs, building signs, and curbside signs. If the roadway design does not provide adequate distance, a speed reduction on the roadway is one way to provide drivers more time to process the information. Any changes to posted speed limits should be accompanied by adequate roadway and roadside design along with speed enforce- ment to accomplish the desired behavioral change (reference Section 3.1.1 for additional detail). Roadways 43 Figure 3.7. MUTCD’s Table 2A-4 “Use of Sign Shapes.”

Minimum spacing of successive signs, such as terminal/airline information, can be calculated by allowing separation of a minimum 3 seconds travel at the operating speed. The following is an example: This is a practical rule of thumb based on several considerations: (1) a study of changeable messages signs finding that the 85th percentile reading time, while driving, was 1 second per major word, (2) eye movement studies showing that drivers are reluctant to look away from the roadway for more than two seconds, and (3) the fact that trucks in an adjacent lane can block view of signs for several seconds. To allow for drivers to read several signs in succession, they should be spaced so as to allow time for each sign to be read, and to allow for drivers to look back at the road between signs. Signs should be visible and located far enough in advance of decision points to allow drivers time to safely read the entire sign message and reach a decision on what to do (e.g., slow down in prepa- ration for turning, change lanes) before reaching the turn or lane split. The more potential lane changes there are, the further in advance the sign must be located. A single lane change requires approximately 10 seconds for gap search and recognition (followed by the physical maneuver); two lane changes require 17 seconds and 3 lane changes 24 seconds13. The operating speed (which may be higher than the posted speed) should be used to determine appropriate sign placement. The MUTCD advises in Section 2A.16 that regulatory and warning signs take precedence over guidance information. This section also contains advice on how to position signs on medians for situations where the roadway curves and how to position signs relative to sidewalks. Refer to Section 3.5 regarding sign illumination and impact on sign legibility when considering sign spacing. 3.4.6.1 Regulatory and Warning Signs The MUTCD is the source for information related to the design, use, and placement of regu- latory and warning signs. The information is contained in the following chapters: • Chapter 2B of the MUTCD contains provisions for regulatory signs, which are typically rectan- gular shaped signs and include Stop and Yield signs. Regulatory signs, as defined by the MUTCD, give notice to road users of traffic laws or regulations. Speed mph ft sec Separation seconds = = = 30 44 3 4 4 132ft ftsec = 44 Wayfinding and Signing Guidelines for Airport Terminals and Landside Figure 3.8. Stages of mental processing and reaction to road signs that illustrate MUTCD section 2A.13.

• Chapter 2C contains provisions for warning signs which are typically diamond shaped. Warn- ing signs, as defined by the MUTCD, give notice to road users of a situation that might not be readily apparent. • Section 2A.16 provides guidance for sign location in terms of distance from the edge of the road and sign height. 3.5 Sign Structures and Illumination 3.5.1 Sign Structures Road signs can be ground mounted on the roadside or mounted overhead on sign structures. In general, signs should be located on the right side of the roadway (MUTCD Section 2A.16) so that they do the following: • Are outside the clear zone unless placed on a breakaway support (see Section 3.5.2), • Optimize nighttime visibility, • Minimize the effects of mud splatter and debris, • Do not obscure each other, • Do not obscure the sight distance to approaching vehicles on the major street for drivers who are stopped on minor-street approaches, and • Are not hidden from view. For added emphasis, supplemental signs may be added to the left side of the roadway. The MUTCD offers guidance on when overhead sign mounting may be justified (Section 2A.17). The following conditions (not in priority order) may be considered in an engineering study to determine if overhead signs would be beneficial: • Traffic volume at or near capacity; • Complex interchange design; • Three or more lanes in each direction; • Restricted sight distance; • Closely spaced interchanges; • Multi-lane exits; • Large percentage of trucks; • Street lighting background; • High-speed traffic; • Consistency of sign message location through a series of interchanges; • Insufficient space for ground-mounted signs; • Junction of two freeways; and • Left exit ramps. For airport applications, it is recommended that overhead signs be used for lane assignment on approach to terminal buildings, particularly for multi-lane facilities, and at any other loca- tions where lane assignment is considered critical for safe and efficient roadway operations. AASHTO offers guidance on sign support materials, types, design, and wind load ratings for large and small signs14,15. These supports should be designed and located in a manner that main- tains a safe roadside environment for all roadway users, and does not distract from the primary purpose of the signs which is to guide, warn and regulate traffic. For these reasons, architectural features and graphic treatments on sign structures (such as banners or other messaging) should be limited and carefully placed if used. Roadways 45

3.5.2 Safety Considerations Sign structures should be mounted on breakaway supports or be shielded by guard rail. Road- way lighting luminaires should also be breakaway. The FHWA offers an informational guide to the various types of sign and lighting structures and supports16. Signs should be placed off the roadway to allow a roadside clear zone to prevent errant vehi- cles from striking sign structures. If such a clear zone can’t be provided because of limited right of way, large sign structures, including static and CMS signs, may need to be protected with crash cushions or guardrails. Additional information can be found in the AASHTO Roadside Design Guide17. Any roadway work zone device, such as temporary signs, barricades, and barrels, must meet crash worthiness standards as well18,19. 3.5.3 Illumination The MUTCD requires roadway signs to be illuminated or to use retroreflective materials in order to provide proper nighttime visibility. Because of the high ambient light levels along road- ways in most major airports (from terminal buildings, parking garages, and landscaping) it may be necessary to use external or internal illumination to provide adequate nighttime visibility for roadway signs. At smaller airports or on the outlying areas of larger airports, with lower ambient light levels, high quality retroreflective materials may provide adequate visibility, particularly for ground-mounted signs. Nighttime testing on-site will be required to make these determinations. The Illuminating Engineering Society provides guidance on roadway sign lighting20. Other factors to consider when deciding between retroreflective materials and external or internal illu- mination are the following: • Traffic volumes; • Complexity of road geometries (i.e., retroreflective material typically works when used head-on, and is not ideal for curving roads); • Obstructions of vehicle headlamps from one sign to the next due to closely spaced signs or landscape elements; and • Need to emphasize decision points or critical information including terminal/airline listings. 3.5.3.1 Retroreflective Sign Sheeting Retroreflective sign sheeting materials return light from vehicle headlamps to the driver’s eyes. Retroreflection is achieved either through microscopic glass beads with a thin metallic backing or through microprisms in a thin polycarbonate film. These materials vary in the daytime color appearance and in their nighttime brightness and efficiency with which they reflect the vehicle headlamps. The FHWA and most states require a minimum level of retroreflectivity for all road- way signs and provide a toolkit to ensure these values are met21. In some airports, the roadway horizontal and vertical geometry is such that considerable care must be taken by the designer in sign location and orientation to ensure that vehicle headlamps will adequately illuminate the sign along the necessary roadway sections. The use of high quality retroreflective sheeting in place of external illumination may also help airports reduce electricity and maintenance costs and reach sustainability goals. Elimination of external illumination also reduces light pollution. 3.5.3.2 External Sign Illumination Roadway lighting is addressed in a guide produced by AASHTO. This guide addresses sign lighting in different ambient lighting conditions. The guide recommends retaining external sign illumination in high ambient conditions. Most major airports would meet this condition22. Sign 46 Wayfinding and Signing Guidelines for Airport Terminals and Landside

lighting that is mounted at the top of a sign structure pointing down may cast shadows during the day that impair the legibility of the sign. Careful consideration must be given to placement of sign lighting to balance daytime appearance and any concerns over upward facing light in an airport environment due to stray light concerns. Environmental conditions can affect sign visibility as well. Frost and dew forming on sign faces can render retroreflective material ineffective23. These conditions are typically transient, and the material recovers without intervention. In areas of high humidity and frequent frost or dew con- ditions, sign lighting may be required to overcome this material deficiency. 3.5.3.3 Internal Illumination Internally illuminated signs can be designed to provide sign recognition and legibility dis- tances comparable to those that are externally illuminated. Proper materials and design must be used for the specific viewing angles present for a specific sign location. Candidate sign materials should be viewed in daylight and dusk conditions to ensure that there is adequate contrast when the sign is not lit. Internally illuminated signs might also help address concerns with stray light expressed with external illumination. 3.6 Changeable Message Signs A Changeable Message Sign (CMS) is a lighted matrix sign that is capable of displaying messages that may be difficult to communicate with standard static signing. These signs are also referred to as Dynamic Message Signs (DMS) or Variable Message Signs (VMS), and these terms are used interchangeably throughout this section. These signs can be mounted in a permanent manner beside or over a roadway, or they may be placed on portable trailers. Small CMS signs may also be placed within a larger static sign, such as when available parking spaces are displayed. Exam- ples of CMS signs are shown in Figures 3.9 and 3.10. 3.6.1 Appropriate Use of Changeable Message Signs The primary function of a CMS is to alert and inform motorists of changing or temporary conditions along their travel path. Changeable signs on major roads should be used only to con- vey messages that change on an hourly, daily, or weekly basis, such as: • Traffic conditions and roadway delays, • Construction or maintenance lane closures or speed reductions, and • Homeland Security threat level. Roadways 47 Figure 3.9. Example of CMS parking information (photos courtesy of Daktronics, Inc.).

In other locations CMS may be used for: • Parking availability and • Parking fee schedules. 3.6.1.1 CMS vs. Static Sign Changeable signs should be used where they are clearly beneficial to accommodate a changing state of operations and to provide convenient and timely information to the passengers and patrons. It is FHWA policy that the appropriate use of a CMS and other types of real-time displays on the normal roadway system should be limited to managing travel, controlling and diverting traf- fic, identifying current and anticipated roadway conditions, or regulating access to specific lanes or the entire roadway24. Airports represent a different environment that has not been investi- gated by FHWA, but many of the same principles and guidance exist in those applications as well. CMS are one of the primary links between a transportation agency and those using the trans- portation facility. The design, display, and management of messages on CMS introduce many challenges for transportation agencies, airports included. Some of these challenges are addressed in The Dynamic Message Sign Message Design and Display Manual25 and The Portable Changeable Message Sign Handbook26. These documents provide comprehensive information on the use of changeable message signs in the typical roadway environment and will be helpful in assessing the use of these signs for an airport. In any case, the CMS should not replace permanent, static signing required in the MUTCD. For construction activities, portable, trailer mounted CMS may be used. A CMS can be an effective permanent and/or temporary traffic control device when used appropriately and coordinated with static signing systems. However, this effect can be dimin- ished if this device is overused or improperly used. Each airport operator should establish or 48 Wayfinding and Signing Guidelines for Airport Terminals and Landside Photo credit: Chris Cunningham Figure 3.10. Tampa International Airport economy parking garage.

endorse a written policy regarding the use of CMS and the authority to display messages should be limited. Many state transportation agencies have published CMS guidelines that may be help- ful references. 3.6.2 CMS Technology Each sign consists of a sign face, the sign housing, and a controller. The signs can be permanent or portable. Permanent signs can vary in size, but normally can display three lines of text with 12 to 18 characters per line. Portable CMS typically have a modular display consisting of three lines of eight characters each. New full matrix sign displays provide the most flexibility, including the abil- ity to vary the height of the characters, display simple graphics, and use proportionally spaced fonts. The most common types of lights used in CMS include: light-emitting diode (LED), fiber optic, incandescent bulb, and reflective disk. A description of these sign types is included in the Texas Transportation Institute (TTI)’s Guidelines on the Use and Operation of Changeable Message Signs27. Control of the sign display can be accomplished via direct connection with a laptop or any number of other methods via a remote computer communicating through an Ethernet modem connection over copper cables, fiber optic cable, radio frequency (RF) links, or cellular transmis- sion. In any case, the use of National Transportation Communications for ITS Protocol (NTCIP) is required to comply with ITS industry communication standards. 3.6.3 Message Design and Layout When CMS are used on airport roadways, their messages must also be carefully constructed to avoid information overload. A CMS must communicate a meaningful message that can be read and understood by motorists within a very short time period. A motorist’s ability to read and under- stand a message depends upon the message load, which refers to the units of information in the total message. CMS messages must also “fit” within and work with the static sign system layout. Lighting conditions vary throughout the day, based on the position of the sun and driver rel- ative to the message sign, and can impact the driver’s ability to read a CMS. Common lighting conditions include: mid-day (sun is overhead), washout (sun is behind driver), backlight (sun is behind sign), and nighttime (no sun). Attention should be given to ensure that CMS messages are readable under prevailing lighting conditions at the location at which they are intended to be used. MUTCD requires that CMS automatically adjust their brightness levels to account for vary- ing light conditions. Other message design features include message content, length, and format. Message content refers to specific information displayed on a CMS. Key elements of message content include information about the event or problem ahead and what the motorist should do about it. Mes- sages are most often displayed in one or two multi-unit message phases. Although the use of three phases is possible, it is not recommended. For roadway applications, FHWA recommends the following guidelines for CMS message phases: • Single Phase Display – Line 1—Describe the problem. – Line 2—Identify location or distance ahead. – Line 3—Provide motorist instruction. • Two-Phase Display – Phase 1—Describe the problem. – Phase 2—Provide motorist instruction. Roadways 49

Message length refers to either the number of words or the number of characters and spaces in a CMS message. With obvious limitations on CMS line capacity, it is usually necessary to deter- mine if the message will fit, then decide if abbreviations can be used or redundant words can be eliminated. Acceptable phrases and abbreviations should be well documented in the airport operator’s policy regarding the use of CMS. Table 1A-2 of the 2009 MUTCD gives acceptable abbreviations for use on changeable message signs. Message format refers to the order and arrangement of the units of information on a CMS. Motorist comprehension and decision-making is enhanced when the proper information is presented in the expected order. Poor formatting can result in driver confusion and increased reading times. More information regarding message content, length, and format can be found in The Dynamic Message Sign Message Design and Display Manual, The Portable Changeable Message Sign Handbook, and the 2009 MUTCD. Each phase of a CMS should be displayed long enough to allow the motorist to read it; how- ever, unnecessarily long display times should be avoided. A phase refers to a message segment that is individually displayed, for example, the first phase may be “Road Work Ahead” and the second phase “Speed Limit 30 mph.” The following display times are recommended in Section 2L.04 of the 2009 MUTCD: Guidance: • The minimum time that an individual phase is displayed should be based on 1 second per word or 2 seconds per unit of information, whichever produces a lesser value. The display time for a phase should never be less than 2 seconds. • The maximum cycle time of a two-phase message should be 8 seconds. • The duration between the display of two phases should not exceed 0.3 seconds. • Compatible units of information should be displayed on the same message phase. Two phases should only be used when absolutely necessary and when both phases contain no more than one unit of information (i.e., the answer to a What? Where? When? question constitutes one unit of information.) Since drivers may first be able to read sign just at the moment the phase changes, the sign letter height, in combination with operating speed, must be designed so that the driver has the opportunity to read three phases per message for a two- phase message. Drivers require at least two seconds of display time per unit of information. A 16-inch letter height sign can be read at a distance of 480 ft (legibility distance is 30 feet per inch of letter height). To display a message with three phases each requiring two seconds, for a total of six seconds, the maximum operating speed would be 55 mph (480/6 = 80 ft/sec, or 55 mph). 3.6.4 CMS Display Elements 3.6.4.1 Letter Size Legibility experiments of CMS character matrix technology had indicated that 18-inch char- acters can be read far enough away by most drivers in optimum daytime viewing conditions to provide 8 seconds of available viewing time while traveling at 70 mph. Another legibility study found that 12-inch characters were sufficient at 45 mph during optimum conditions28. However, optimum conditions often do not exist due to weather and/or other factors. The MUTCD provides further guidance regarding letter height in Section 2L.04: Word messages on changeable message signs should be composed of all upper-case letters. The mini- mum letter height should be 18-inches (450 mm) for changeable message signs on roadways with speed limit of 45 mph (70 km/h) or higher. 50 Wayfinding and Signing Guidelines for Airport Terminals and Landside

Based on this information, a minimum letter height of 12 inches is recom- mended for roadways with operating speeds less than 45 mph, and 18 inches for roadways with operating speeds of 45 mph or more. Recommended letter heights are shown in Figure 3.11. 3.6.4.2 Font New CMS technologies allow denser pixel placement and a wider variety of fonts and letter forms than in the past. The MUTCD does not specify a font to be used on CMS. It does provide guidance statements that encourage minimum visibility and legibility distances in Section 2L.03 Paragraph 4. Additional sections (2L.04) provide guidance on letter stroke width, height: width ratio, character spacing, and use of upper and lower case letters. 3.6.4.3 Color Typical roadway CMS signs generally contain white, yellow, amber, or fluorescent yellow- green legends on a black background. Full matrix LED sign displays are also capable of display- ing full color text and graphics, but use of some of these colors may actually increase driver recognition and comprehension times. Although these colors may have greater target value than other colors, the novelty of these signs may prevent their recognition as traffic control devices. The sign structural support and housing materials should be selected with care so as not to distract from the message being displayed. The housing should also be neutral enough that the CMS is recognized by drivers as a traffic control device and not an advertisement. In support of this concept, the MUTCD contains the following language in Section 2L.02: Standard: When a changeable message sign is used to display a safety, transportation-related, emergency homeland security, or AMBER alert message, the display format shall not be of a type that could be con- sidered similar to advertising displays. Research shows that white or amber is preferred for CMS letter colors. The use of red is not recommended. In addition, Section 2L.04 of the MUTCD discourages the use of CMS in a manner that may be distracting to drivers: Standard: Changeable message signs shall not include advertising, animation, rapid flashing, dissolving, exploding, scrolling, or other dynamic elements. 3.6.5 Passenger Advisory CMS With security taking a high priority in airport activities, there is a need to communicate ele- vated risks to travelers. The Homeland Security Advisory System uses a color-coded system to place citizens and public officials on notice about the likelihood of a terrorist attack. The more specific and imminent the threat, the higher the threat level is set. The threat level changes peri- odically, so changeable message signs can offer an avenue for communicating these changes in the airport environment. If public agencies decide to display emergency or security alert messages on a CMS, FHWA has determined that this application is acceptable if public agencies have developed policies and procedures that govern the messages that are displayed on CMS and their operation. The pub- lic agency policy and procedures relating to displaying emergency or security alert messages on CMS must address the following issues: An FHWA memorandum dated March 21, 2003, addresses Use of Changeable Message Sign (CMS) for Emergency Security Messages64: • The criteria under which CMS will be used for emergency or security alert messages, includ- ing the necessary coordination with public safety or security agencies. Formal policies among Roadways 51 Operating Speed (mph) Recommended Letter Height (inches) Less than 45 mph 12 45 mph or more 18 Figure 3.11. Recommended CMS letter heights.

critical stakeholders (such as law enforcement, security, transportation, and public safety) can be used to establish these agreed upon criteria. • Protocols or hierarchy for prioritizing messages and determining which messages are to be displayed. • Geographic area over which the information is to be displayed, to be determined in coopera- tion with public safety and security agencies. • Identification of the circumstances under which transportation-related messages, such as lane closures, fog alerts, detours, or other messages that may be needed because of dangerous travel conditions in the immediate vicinity, would preempt emergency or security alert messages. • The criteria that would cause the discontinuation of use of the CMS if the emergency or secu- rity alert message creates an adverse traffic impact such as queues, markedly slowing traffic, etc. • Methodology for developing and displaying messages that are appropriate for CMS display including, but not limited to, standard message sets. Agencies should follow the recommended national CMS practices related to the development, use of text, manner in which messages should be displayed, human factors related to understandability of the messages, and how CMS are operated. 3.7 Sign Maintenance In 2008, FHWA passed rules concerning minimum sign retroreflectivity values. These are listed in Table 2A-3 of the MUTCD. These standards require a sign maintenance plan that ensures that minimum levels of retroreflectivity are maintained to provide adequate visibility. The following five different methods of regular inspection of sign retroreflectivity are allowed: • Visual nighttime inspections, • Measured retroreflectivity, • Expected life, • Blanket replacement, and • Control signs. Sign retroreflectivity can be incorporated into an overall asset management plan. Expected life of sign materials and structures can be included in the plan to expedite routine replacement and maintenance. The retroreflective material on a sign can be expected to last 7–12 years depending on the type of material selected and its sun exposure. Ground-mounted signs may need to be cleaned annually to remove dirt and mud, particularly those in splash zones and near areas where vehicle idling may produce soot build-up. Annual daytime and nighttime visual drive-by inspections are recommended as part of a maintenance schedule. Sign supports, crash cushions, and guardrails may need routine maintenance and inspection as well depending on the system used. Manufacturer’s recommendations should be followed to check for rust, loose bolts, etc. 52 Wayfinding and Signing Guidelines for Airport Terminals and Landside

Next: Chapter 4 - Parking »
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TRB’s Airport Cooperative Research Program (ACRP) Report 52: Wayfinding and Signing Guidelines for Airport Terminals and Landside is designed to provide airports with the tools necessary to help passengers find their way in and around the airport.

The guidelines focus on four areas of the airport: (1) roadways—both on-airport, and off-airport access roads; (2) parking; (3) curbside and ground transportation; and (4) terminal.

In addition, the guidelines discuss developing a wayfinding strategy; the use of technology and visual displays; and color, fonts, and sizes.

View the Impact on Practice for this report.

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