Cover Image

Not for Sale



View/Hide Left Panel
Click for next page ( 30


The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 29
CHAPTER 3 Roadways 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

OCR for page 29
30 Wayfinding and Signing Guidelines for Airport Terminals and Landside 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.

OCR for page 29
Roadways 31 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.

OCR for page 29
32 Wayfinding and Signing Guidelines for Airport Terminals and Landside 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.