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Roadways 37 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.

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38 Wayfinding and Signing Guidelines for Airport Terminals and Landside 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.

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Roadways 39 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 TM 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 ClearviewTM typeface 1012% 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 ClearviewTM font is used by several airports, including Dallas/Fort Worth as shown in Figure 3.3. The use of ClearviewTM 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 ClearviewTM 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

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40 Wayfinding and Signing Guidelines for Airport Terminals and Landside 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. Figure 3.4. Typical arrow shapes from MUTCD figure 2D-2.

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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. 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.

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42 Wayfinding and Signing Guidelines for Airport Terminals and Landside 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. Figure 3.6. Color coding example from the 2009 MUTCD Figure 2D-1.

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Roadways 43 Figure 3.7. MUTCD's Table 2A-4 "Use of Sign Shapes." 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).

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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. 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: Speed = 30 mph = 44 ft sec Separation = 3 seconds 44 ft sec = 132 ft 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.