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Designing Sidewalks and Trails for Access

Chapter 4 - Sidewalk Design Guidelines and Existing Practices

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4.4.3 Driveway Crossings

Driveway crossings permit cars to cross the sidewalk and enter the street, and they consist of the same components found in curb ramps. It is the driver's responsibility to yield to the pedestrian at the driveway–sidewalk interface.

Figure 4-32: Driveway crossings without landings confront wheelchair users with severe and rapidly changing cross-slopes at the driveway flare.

Figure 4-32: Driveway crossings without landings confront wheelchair users with severe and rapidly changing cross-slopes at the driveway flare.

Figure 4-33: When sidewalks have a planter strip, the ramp of the driveway does not interfere with a pedestrian's path of travel.

Figure 4-33: When sidewalks have a planter strip, the ramp of the driveway does not interfere with a pedestrian's path of travel.

Figure 4-34: On wide sidewalks, there is enough room to provide a ramp for drivers and retain a level landing for pedestrians.

Figure 4-34: On wide sidewalks, there is enough room to provide a ramp for drivers and retain a level landing for pedestrians.

Figure 4-35: Jogging the sidewalk back from the street provides a level landing for pedestrians on narrow sidewalks.

Figure 4-35: Jogging the sidewalk back from the street provides a level landing for pedestrians on narrow sidewalks.

Figure 4-36: Although parallel driveway crossings provide users with level landings, users continuing on the sidewalk are forced to negotiate two ramps.

Figure 4-36: Although parallel driveway crossings provide users with level landings, users continuing on the sidewalk are forced to negotiate two ramps.

Figure 4-37: Inaccessible sidewalk caused by many individual parking lots.

Figure 4-37: Inaccessible sidewalk caused by many individual parking lots.

Figure 4-38: Improved accessibility created by combining parking lots and reducing the number of entrances and exits.

Figure 4-38: Improved accessibility created by combining parking lots and reducing the number of entrances and exits.

Intersections of driveways and sidewalks are the most common locations of severe cross-slopes for sidewalk users. Some inaccessible driveway crossings have cross-slopes that match the grade of the driveway because a level area is not provided for the crossing pedestrian.This type of crossing can be very difficult for people who use wheelchairs or walking aids (Figure 4-32).

Rapid changes in cross-slope usually occur at driveway flares and are most problematic when they occur over a distance of less than 0.610 m (24 in), or the approximate length of a wheelchair wheelbase. As the wheelchair moves over the surface of a severely warped driveway flare, it will first balance on the two rear wheels and one front caster. As the

Wide sidewalks can be designed similar to sidewalks with a setback if the upper portion of the sidewalk is leveled for pedestrians and the bottom portion is sloped for automobiles (Figure 4-34).

A level landing area can be achieved on narrow sidewalks if the sidewalk is jogged back from the street as it crosses the driveway (Figure 4-35). Purchasing additional land to jog the sidewalk back should be strongly considered when there is not enough space for a level sidewalk.

Similar to a parallel curb ramp, a parallel driveway crossing provides a level landing by lowering the sidewalk to the grade of the street (Figure 4-36). This design is preferable to the severe cross-slopes at some driveway crossings, but it is not as easy to negotiate as setback and wide sidewalk designs. With this type of crossing, drivers assume that they can speed up on the level portion next to the street. In addition, the parallel ramp can produce steep grades on both sides of the driveway and initiate drainage problems on the landing.

Commercial districts with front parking between the sidewalk and the buildings are often designed with a series of individual lots with individual entrances and exits (Figure 4-37).This design increases the number of driveway crossings and forces pedestrians to encounter automobiles repeatedly. If the driveway crossings do not have level landings, people with mobility disabilities must also repeatedly negotiate severe cross-slopes.To improve access for all pedestrians,including pedestrians with mobility disabilities, individual parking lots should be combined to reduce the number of entrances and exits. The remaining driveway crossings should be retrofitted to include level landings (Figure 4-38).

4.4.4 Medians and Islands

Medians and islands help pedestrians cross streets by providing refuge areas that are physically separated from the automobile path of travel. A median separates opposing lanes of traffic. An island is a protected spot within a crosswalk for pedestrians to wait to continue crossing the street or to board transportation such as a bus. Medians and islands are useful at irregularly shaped intersections, such as where two roads converge into one (Earnhart and Simon, 1987).

Medians and islands reduce the crossing distance from the curb and allow pedestrians to cross during smaller gaps in traffic. Examples of cut-through medians and ramped and cut-through islands are shown in Figure 4-39 and 4-40. Medians and islands are useful to pedestrians who are unable to judge distances accurately. Medians and islands also help people with slow walking speeds cross long intersections with short signal cycles. Because medians and islands separate traffic into channels going in specific directions, they require crossing pedestrians to watch for traffic coming in only one direction.

According to ADAAG, a raised island or median should be level with the street or have curb ramps at all sides and a level area 1.220 m (48 in) long in all directions.If a cut-through design is used, it should be at least 0.915 m (36 in) wide. Cutthrough medians are easier for wheelchair users and other people with mobility impairments to negotiate than ramps.In addition, the edge of a cut-through can provide directional information to people with visual impairments. However, if the cut-through is too wide, people with visual impairments might not detect the presence of a median or island. For this reason,the width of the cut-through should be limited to ensure detection by people with visual impairments.A detectable warning on the surface of the cut-through will also improve detectability.

4.4.5 Crosswalks

Crosswalks are a critical part of the pedestrian network. A crosswalk is defined as "the portion of a roadway designated for pedestrians to use in crossing the street" and may be either marked or unmarked (Institute of Transportation Engineers, Technical Council Committee 5A-5, 1998).

Figure 4-39: Cut-through corner island and center median (based on OR DOT, 1995).

Figure 4-39: Cut-through corner island and center median (based on OR DOT, 1995).

Figure 4-40: Ramped corner island and cut-through median (based on OR DOT, 1995).

Figure 4-40: Ramped corner island and cut-through median (based on OR DOT, 1995).

Figure 4-41: Two horizontal lines are the most common crosswalk markings.

Figure 4-41: Two horizontal lines are the most common crosswalk markings.

Figure 4-42: A ladder design was found to be the most visible type of pedestrian crosswalk marking.

Figure 4-42: A ladder design was found to be the most visible type of pedestrian crosswalk marking.

Figure 4-43: Diagonal markings enhance visibility.

Figure 4-43: Diagonal markings enhance visibility.

Marked crosswalks are most effective when they can be identified easily by motorists. However, many pedestrians,including pedestrians with low vision,benefit from clearly marked crosswalks.For this reason, proposed Section 14 (1994) required marked crossings to be "delineated in materials or markings that provide a visual contrast with the surface of the street" (U.S. Access Board,1994b). Most State DOTs follow the Manual of Uniform Traffic Control Devices (MUTCD) guidelines for marking crosswalks. Although the MUTCD does permit some variations for additional visibility, the basic specifications call for solid white lines not less than 150 mm (6 in) marking both edges of the crosswalk and spaced at least 1.830 m (72 in) apart (US DOT, 1988) (Figure 4-41). A study by Knoblauch, Testin, Smith, and Pietrucha (1988) found the ladder design, shown in Figure 4-42, to be the most visible type of crosswalk marking for drivers. Diagonal striping can also enhance the visibility of a pedestrian crossing (Figure 4-43).

When a diagonal curb ramp is used at an intersection, a 1.220-m (48-in) clear space should be provided to allow ramp users enough room to maneuver into the crosswalk.

In some situations, marked crosswalks might not be enough to ensure pedestrian safety. For example, at high-speed intersections without traffic signals, drivers often cannot perceive a marked crosswalk quickly enough to react to pedestrians in the roadway. This problem is compounded by the fact that "pedestrians may 'feel safer' within a marked crosswalk and expect motorists to act more cautiously" (Institute of Transportation Engineers, Technical Council Committee 5A-5, 1998). Some agencies around the United States consider that removing crosswalk markings improves pedestrian safety.Alternative treatments such as electronically activated crosswalks,pedestrian-actuated traffic controls,flashing traffic signals, light guard flashing crosswalks, traffic calming measures, raised crosswalks, and traffic signals are also being used. FHWA studies are currently being conducted to determine if these measures provide safer crossing for pedestrians.

Most marked crosswalks observed during the sidewalk assessments were marked with paint. Others were built with contrasting materials such as red brick inside the crosswalk, bordered with gray concrete. Contrasting textures can provide tactile guidance for people with visual impairments, as well as visible colorized warnings.

4.4.6 Crossing Times

People's walking pace and starting pace varies depending on their personal situation. Older pedestrians might require longer starting times to verify that cars have stopped. They also might have slower reaction times and slower walking speeds. Powered wheelchair users and manual wheelchair users on level or downhill slopes might travel faster than other pedestrians. But on uphill slopes,manual wheelchair users might have slower travel speeds. At intersections without audible pedestrian signals,people with visual impairments generally require longer starting times because they rely on the sound of traffic for signal-timing information.

The AASHTO Green Book indicates that "average walking speeds range from 0.8 to 1.8 m/s." The MUTCD assumes an average walking speed of 1.220 m/s (4 ft/s). However, research on pedestrian walking speeds has demonstrated that more than 60 percent of pedestrians walk more slowly and that 15 percent of pedestrians walk at less than 1.065 m/s (3.5 ft/s) (Kell and Fullerton, 1982).The AASHTO Green Book recommends a walking rate of 1.0 m/s (39 in/s) for older pedestrians (AASHTO, 1995).

Pedestrians of all mobility levels need to cross intersections. However, when crossing times accommodate only people who walk at or above the average walking speed, intersections become unusable for people who walk at a slower pace.To accommodate the slower walking speeds of some pedestrians, transportation agencies should consider extending their pedestrian signal cycles. Signal timing should be determined on a case-by-case basis, although extended signal cycles are strongly recommended at busy intersections that are unusually long or difficult to negotiate.

4.4.7 Pedestrian-Actuated Traffic Controls

Pedestrian-actuated traffic controls require the user to push a button to activate a walk signal. According to the MUTCD, pedestrian-actuated traffic controls should be installed when a traffic signal is installed under the Pedestrian Volume or School Crossing warrant, when an exclusive pedestrian phase is provided, when vehicular indications are not visible to pedestrians,and at any established school crossings with a signalized intersection (US DOT,1988). If the intersection has a median,a button should be added to the median and both corners.

Unfortunately, pedestrian-actuated control signals are often inaccessible to people with mobility impairments and people with visual impairments.To be accessible to wheelchair users and people with limited mobility, pedestrianactuated traffic controls need to be located as close as possible to the curb ramp without reducing the width of the path. They also need to be mounted low enough to permit people in wheelchairs to reach the buttons. ADAAG does not specify a height for pedestrian-actuated control systems. However, ADAAG Section 4.10.3 states that elevator buttons should be located no higher than 1.065 m (42 in) (ADAAG, U.S. Access Board,1991).

The size and type of the button also affect the accessibility of the control. Larger raised buttons are easier for people with visual impairments to identify (Figure 4-44). According to proposed Section 14 (1994), buttons should be raised above or flush with their housings and be at least 50 mm (2 in) in the smallest dimension (U.S. Access Board, 1994b).

Figure 4-44: A large, easy-to-press button makes pedestrianactuated traffic controls more usable for people with limited hand strength and dexterity.

Figure 4-44: A large, easyto- press button makes pedestrianactuated traffic controls more usable for people with limited hand strength and dexterity.

Pedestrian-actuated control buttons require more force to operate than most indoor buttons. However, people with limited hand strength or dexterity might be able to exert only a limited amount of force.To address this need, proposed Section 14 (1994) recommended that the force required to activate controls should not be greater than 22.2 N (5 lbf) (U.S. Access Board,1994b).

People with visual impairments might be at a disadvantage at intersections with pedestrian-actuated crossing controls if they are unaware that they need to use a control to initiate a pedestrian crossing signal. At an intersection with a pedestrian-actuated control button, a person with a visual impairment must detect whether a signal button is present,then push it and return to the curb to align for the crossing. This process might require several signal cycles if the button is not located within easy reach of the curb edge. People with visual impairments can confirm the presence of and locate pedestrian-actuated crossing controls more easily if the controls emit sounds and/or vibrations.To address the need for pedestrian-actuated control signals that are accessible to people with visual impairments,TEA-21 provides funding for "the installation,where appropriate,and maintenance of audible traffic signals and audible signs at street crossings" (TEA-21, 1998).Accessible pedestrian signals that accommodate people with visual impairments are discussed in Section 4.4.2.6 of this report.

Many varieties of controls were observed during the sidewalk assessments. The most accessible were relatively large and could be activated with little force. Those that were least accessible were small,required significant force to activate, and were located far from the logical crossing point. Some pedestrian-actuated traffic controls were positioned so that users standing at the edge of the sidewalk had to walk around traffic poles to reach the control button. In other instances,obstacles such as newspaper stands were placed in front of the controls, blocking access to the trigger mechanism.Intersections with awkwardly placed pedestrian-actuated controls can be made more accessible by moving the control to a more easily reached location or altering the signal timing to allow pedestrians to realign themselves for a crossing before the light changes.

4.4.8 Midblock Crossings

Midblock crossings are pedestrian crossing points that do not occur at intersections. They are often installed in areas with heavy pedestrian traffic to provide more frequent crossing opportunities. For midblock crossings to be accessible to people with mobility impairments, a curb ramp needs to be installed at both ends of the crossing along a direct line of travel. If the curb ramps are offset, pedestrians who rely on the curb ramps are forced to travel in the street.

For midblock crossings to be accessible to people with visual impairments, they need to be detectable.At midblock crossings, pedestrians with visual impairments do not have the sound of parallel traffic available to identify a midblock crossing opportunity. If a traffic signal is installed,an audible indicator that provides timing information should also be included.Audible or vibrotactile information is effective in alerting people with visual impairments of a midblock crossing.

Midblock crossings spanning multiple lanes can be difficult for some pedestrians to cross. In these situations, curb extensions can be effective in reducing crossing times and increasing visibility between pedestrians and motorists (Figure 4-45). A median is another effective method to reduce crossing distances.

4.4.9 Sight Distances

Sight distance is defined as "the distance a person can see along an unobstructed line of sight" (University of North Carolina, Highway Safety Research Center, 1996). Adequate sight distances between pedestrians and motorists increase pedestrian safety. Motorists also need appropriate sight distances to see traffic signals in time to stop. Vertical sight distance can be important for drivers of high vehicles such as trucks and buses, whose sight lines might be blocked by trees or signs (ibid.).Although bollards, landscaping, parking, benches,or bus shelters make pedestrian areas more inviting by calming traffic and providing amenities, they can also clutter the environment and block sight lines between motorists and pedestrians waiting to cross the intersection.

Figure 4-45: Curb extensions at midblock crossings help reduce crossing distance.

Figure 4-45: Curb extensions at midblock crossings help reduce crossing distance.

Figure 4-46: Sight line obstructed by parked cars prevents drivers from seeing pedestrians starting to cross the street.

Figure 4-46: Sight line obstructed by parked cars prevents drivers from seeing pedestrians starting to cross the street.

Trimming vegetation, relocating signs,and hanging more than one sign or traffic signal on one arm pole where permitted by MUTCD can improve sight distances at corners.Parked cars near the intersection or midblock crossing can also reduce sight distances (Figure 4-46).Installing curb extensions physically deters parking at intersection corners and improves the visibility of pedestrians, as shown in Figures 4-47 and 4-48. Curb extensions can also increase the angle at which pedestrians meet motor vehicles,improving the visibility of both (OR DOT,1995). In addition, curb extensions shorten crossing distances and provide sidewalk space for curb ramps with landings.

Figure 4-47: Partial curb extensions improve visibility between pedestrians and motorists.

Figure 4-47: Partial curb extensions improve visibility between pedestrians and motorists.

Figure 4-48: Full curb extensions improve visibility between pedestrians and motorists.

Figure 4-48: Full curb extensions improve visibility between pedestrians and motorists.

Figure 4-49: Pedestrian and biker underpass.

Figure 4-49: Pedestrian and biker underpass.

4.4.10 Grade-Separated Crossings

Grade-separated crossings are facilities that allow pedestrians and motor vehicles to cross at different levels. Some grade separated crossings are very steep and are difficult for people with mobility impairments to negotiate. In addition, grade-separated crossings are extremely costly to construct and are often not considered pedestrian-friendly because pedestrians are forced to travel out of their way to use the underpass or overpass. The effectiveness of a grade-separated crossing depends on whether or not pedestrians perceive that it is easier to use than a street crossing (Bowman, Fruin, and Zegeer, 1989).

Examples of grade-separated crossings include the following (Institute of Transportation Engineers Technical Council Committee 5A-5, 1998):

Figure 4-49 illustrates a pedestrian underpass.

The needs of pedestrians should be a high priority at grade-separated crossings.If designed correctly, grade-separated crossings can reduce pedestrian-vehicle conflicts and potential accidents by allowing pedestrians to avoid crossing the path of traffic. They can also limit vehicle delay, increase highway capacity, and reduce vehicle accidents when appropriately located and designed.Grade-separated crossings can improve pedestrian safety, reduce travel time,and serve to maintain the continuity of a neighborhood in which high-traffic roads run through residential areas (University of North Carolina,Highway Safety Research Center, 1996).

Grade-separated crossings are most efficient in areas where pedestrian attractions such as shopping centers, large schools,recreational facilities, parking garages,and other activity centers are separated from pedestrian generators by highvolume and/or high-speed arterial streets.

Well-designed grade-separated crossings minimize slopes,feel open and safe,and are well lit. Minimizing the slope of a grade-separated crossing is often difficult because a significant rise,generally from 4.3 to 5.5 m (14 to 18 ft),must be accommodated. Inaccessible grade-separated crossings should not be constructed. In some situations, elevators can be installed to accommodate people with mobility impairments.

Underpasses might invite crime if insufficiently lit and seldomly traveled.Underpasses can also be more expensive to install than other pedestrian facilities because a tunnel must be dug and utility lines relocated. Tunnels are more inviting to use when they are brightened with skylights or artificial lighting and are wide and high enough to feel open and airy (ibid.).

4.4.11 Roadway Design

Sidewalk accessibility is intimately affected by the design of roads. Factors affecting roadway safety and accessibility for pedestrians include sight distance, design speed, location, cross-slope, grade, and the functional class of the road.Although some States have their own guidelines, most roadway designers rely on the AASHTO Green Book for street development specifications. The AASHTO Green Book recognizes several general factors as important to the functionality of public rights-of-way, including the grade of the road, cross-slopes, traffic control devices, curbs, drainage, the road crown, and roadway width (Table 4-1).

Table 4-1:Grade, Cross-Slope, and Curb Height Guidelines by Functional Class of Roadway (based on information contained in AASHTO, 1995)

Road TypeMaximum Grade(%)¹
Level/Rolling/Mountain
Cross-
Slope3(%)
Curb Height (mm)Sidewalk Coverage
Urban localConsistent with terrain
<15.0/<8.02
1.5–6.04100–225Commercial both sides Residential at least one side
Rural local8.0/11.0/16.01.5–6.04n/an/a5
Urban collector9.0/12.0/14.01.5–3.0150–225Same as Urban local
Rural collector7.0/10.0/12.01.5–3.0n/an/a5
Urban arterial8.0/9.0/11.01.5–3.0150–225n/a5
Rural arterial5.0/6.0/8.01.5–2.0n/an/a5
Recreational8.0/12.0/18.0n/an/an/a5

Chart does not include figures for freeways or divided arterials, which are not designed for pedestrians and are not built with sidewalks.

1The lower the maximum speed permitted on the road, the steeper the grade is permitted to be. The numbers listed in the chart represent the lowest road speeds indicated in the AASHTO Green Book.

2Residential/commercial or industrial.

3The numbers listed in the chart indicate what the cross-slope should generally be for proper drainage.

4Cross-slopes ranging from 3.0 to 6.0 percent should be used only for low surface types such as gravel, loose earth, and crushed stone.

5Sidewalks are still needed, even though the AASHTO Green Book does not specify guidelines for sidewalk coverage along this road.

The functionality of a roadway should be balanced with the needs of pedestrians.Too often, roadway design prioritizes the needs of motorists, and pedestrians are put at risk. Pedestrians would be well accommodated if they received the same design considerations as drivers. When a sidewalk is included along a roadway, it must be accessible according to the ADA regulations. To accomplish this task,roadway designers must understand how roadway designs impact pedestrians and prioritize accessible road development.

The manner in which roads are maintained also impacts pedestrians. Asphalt, an economical and durable material, is used to pave most roads. In the past, repairing damage to asphalt roads typically entailed overlaying the existing pavement with more asphalt. Over time, the asphalt layers build up the roadway crown and can create steep slopes on either side of the centerline. These slopes can be difficult for crossing pedestrians to negotiate (Figure 4-50) and create rapidly changing grades at curb ramps.

Figure 4-50: When roads are not milled, layers of asphalt build up and make the crossing difficult for wheelchair users and others.

Figure 4-50: When roads are not milled, layers of asphalt build up and make the crossing difficult for wheelchair users and others.

Figure 4-51: Milling roads from gutter to gutter prevents rapidly changing grades and makes intersections easier for wheelchair users to negotiate.

Figure 4-51: Milling roads from gutter to gutter prevents rapidly changing grades and makes intersections easier for wheelchair users to negotiate.

Because used asphalt can now be recycled, it is currently more common for roads to be milled before they are resurfaced.To improve accessibility, roads should always be milled before being resurfaced.The same amount of asphalt to be added to a road should be milled away prior to any resurfacing project. Milling should be completed from gutter to gutter to avoid crowning (Figure 4-51).In addition, because the US DOJ has indicated that "resurfacing beyond normal maintenance is an alteration,"accessibility improvements such as curb ramp installations must also be incorporated into road resurfacing projects (US DOJ, 1994).

4.4.12 Drainage

Sidewalks and sidewalk elements, such as curb ramps and driveway crossings, must be designed to provide efficient drainage as well as good access. Sidewalks provide the main conduit for draining the walking surface, adjacent properties, and, in some cases, the roadway. Sidewalks with poor drainage can accumulate precipitation that is not only a nuisance but might impede access or endanger the health, safety, and welfare of all pedestrians. For example,poorly drained sidewalks in cold climates can freeze over with ice and cause a hazard for pedestrians. Poorly drained sidewalks also permit the accumulation of silt and debris, further impeding access.The AASHTO Green Book, adopted by most States, provides slope ranges based on street type (Table 4-1).

Local topography and weather conditions also affect how steeply sidewalks, gutters,and roads should be sloped to provide adequate drainage. According to the AASHTO Green Book, a cross-slope between 1.5 to 2.0 percent provides effective drainage on paved surfaces in most weather conditions (AASHTO, 1995).

Gutters are generally sloped more steeply than the roadway to increase runoff velocity. Concrete gutters are smoother,offer less resistance to runoff, and are more water-resistant than asphalt, but they are also more expensive to install.According to the AASHTO Green Book,gutters should have "a cross-slope of 5 to 8 percent to increase the hydraulic capacity of the gutter section" (AASHTO,1995). ADAAG specifies a 5 percent maximum slope at gutters (ADAAG,U.S. Access Board, 1991). This provision helps prevent wheelchair users from hitting their footrests on the ramp or gutter and potentially being thrown forward out of their wheelchairs. Section 4.3.1 contains additional information on rate of change of grade and gutter design.

A wider gutter can be used to drain larger volumes of water without increasing the slope experienced by curb ramp users.However, widening the gutter might require the purchase of additional rightof-way. According to the AASHTO Green Book, gutters formed in combination with curbs should range from 0.3 m to 1.8 m (12 in to 71 in) wide (AASHTO, 1995).

Barrier curbs are higher than other types of curbs to discourage vehicles from leaving the roadway (AASHTO, 1995).The height and more perpendicular face of barrier curbs also help sidewalks from being inundated in areas prone to flooding.High curbs can also cause curb ramps to be longer and occupy more sidewalk or street space. These restrictions make it more difficult to install accessible ramps on narrower sidewalks.

Storm drains and catch basins are normally placed where they will intercept surface water runoff. Installing a curb ramp at a point of strategic runoff interception can compromise effective drainage. Regrading the section of road or curb ramp location to alter drainage patterns can resolve some situations in which drainage concerns conflict with accessibility requirements.Ideally, inlets should be placed uphill of crossings or curb ramps to drain water before it can puddle where pedestrians are crossing. In locations with heavy rainfall,more frequent drainage inlets, more strategic placement of inlets, and basin pickups will also reduce the frequency of puddles.

4.4.13 Building Design

Newly constructed buildings are required to be accessible under Titles II and III of the ADA. Building entrances must be at grade with the sidewalk or provide accessible ramps to bridge elevation changes between the building and the street. In some existing facilities, a significant elevation difference exists between the street and the finished floor elevation (FFE) of the building. Inaccessible building entrances with stairs or sidewalks with significant cross-slopes are often the result (Figures 4-52 and 4-53).

Figure 4-52: Stairs bridging low street elevation and high finished-floor elevation prevent wheelchair access into the building.

Figure 4-52: Stairs bridging low street elevation and high finished-floor elevation prevent wheelchair access into the building.

Figure 4-53: Steep cross-slopes bridging low street elevation and high finished-floor elevation make the sidewalk difficult for wheelchair users to travel across.

Figure 4-53: Steep cross-slopes bridging low street elevation and high finished-floor elevation make the sidewalk difficult for wheelchair users to travel across.

Factors influencing the FFE of a building can include zoning ordinances, building codes, and conditions such as geologic formations, topography, and the hydrologic makeup of an area. The requirements of other agencies, including the Federal Emergency Management Agency (FEMA),the Army Corps of Engineers, and the Federal Aviation Administration, as well as wetland laws, can also influence the FFE of buildings in a given region. For example, FEMA requires communities located within flood plains to elevate buildings above expected water rise levels. Such safety recommendations are commonly included in local building codes. Insurance companies might demand higher FFEs if coverage for flood damage is desired.

When sidewalk design is not given sufficient emphasis by transportation planning and review processes, sidewalk designers are left to bridge the gap between building and street elevations.Creative solutions include providing a level area and sloping the edge of the path,or raising the curb to level the sidewalk (Figures 4-54 and 4–55).

Figure 4-54: A level area at least 0.915 m (36 in) wide improves access when there is a low street elevation and high finishedfloor elevation.

Figure 4-54: A level area at least 0.915 m (36 in) wide improves access when there is a low street elevation and high finishedfloor elevation.

Figure 4-55: A higher curb provides a level pathway but might increase the slope of curb ramps if the sidewalk is narrow.

Figure 4-55: A higher curb provides a level pathway but might increase the slope of curb ramps if the sidewalk is narrow.

Road, sidewalk, and building designers should coordinate their efforts to ensure that accessible sidewalks are developed in new construction and alterations.Good review processes, including a variety of interest groups, can ensure that construction plans for accessible sidewalks are implemented.

Transportation agencies differ greatly in the degree to which they address pedestrian facilities. Some areas permit developers to exclude sidewalk plans from the review of the overall construction plan and create inaccessible pathways and noncompliant buildings, while others make consideration of sidewalk plans mandatory. The disparity in the types of requirements builders and developers must meet was illustrated in a 1995 National Association of Home Builders (NAHB) survey. The survey revealed that, while 94 percent of builders and developers had to obtain building permits, only 36 percent were required to undergo plan checking, and only 19 percent were required to design sidewalks more than 1.220 m (48 in) wide (NAHB, 1995).

4.4.14 Maintenance

Sidewalks are prone to damage caused by environmental conditions. Maintaining sidewalk elements in good condition is an essential part of providing access to public rights-of-way. Sidewalks in poor repair can limit access and threaten the health and safety of pedestrians. If sidewalks are in poor condition or nonexistent, pedestrians are forced to travel in the street.

A public information program by the Campaign to Make America Walkable indicated that 3 of the top 10 most frequently cited roadway safety and sidewalk design problems were the following maintenance issues (The Campaign to Make America Walkable,1997):

  1. Missing sections of sidewalk,especially on key walking routes
  2. Bad sidewalk surfaces, i.e., uneven or broken concrete or uplifted slabs over tree roots
  3. Bad sidewalk maintenance, i.e.,overhanging bushes or trees or unshoveled snow on sidewalks

Maintenance problems are usually identified by pedestrians who report the location to the municipal authorities.Identification of locations requiring maintenance may be done in conjunction with a city's accessibility improvement program. Effective maintenance programs are quick to identify conditions that can impede access and respond with repairs.Some cities survey and repair all sidewalks in regular cycles. Other cities make or enforce repairs only if a complaint is filed. Cities also might have pavement management programs and personnel devoted entirely to inspecting and repairing damaged access routes. Assessing sidewalks for accessibility should be an integral part of maintenance survey programs.

Sidewalk inspectors typically look for conditions that are likely to inhibit access or cause pedestrians to injure themselves.The following list of common sidewalk maintenance problems was generated from promotional material created for home owners by the Bureau of Maintenance in the City of Portland, Oregon (1996) and the Division of Engineering for the Lexington–Fayette County Urban Government (1993):

Although sidewalks are elements of the public right-of-way, many city charters assign the owner of the adjacent property with responsibility for sidewalk upkeep. It is common for city charters to specify that the city cannot be held liable for any accident or injury due to sidewalk conditions.

Home owners are commonly allowed to decide whether to hire a contractor, perform repairs on their own, or have the city do the repair. The home owners' association in some neighborhoods address right-of-way maintenance to minimize the cost to individual members. Some cities subsidize property owners for repairing sidewalks. Local laws also might dictate whether a home owner must engage a professional contractor to undertake sidewalk repair. If municipal inspectors review and approve sidewalk repairs, the finished sidewalks are more likely to meet pedestrian access needs.

4.4.15 Signs

Most agencies rely on the MUTCD for sign guidelines. For font recommendations, the MUTCD references the Standard Alphabets for Highway Signs and Pavement Markings, which permits a series of six letter types on signs. Each letter type features a different stroke width-to-height ratio (Office of Traffic Operations, FHWA, 1982). Various sign shapes, colors, and lettering are used for each type of sign (warning, street, regulatory, etc.) (US DOT, 1988). Braille and raised lettering are not addressed in the MUTCD.

ADAAG Section 4.30 also provides guidelines for signage. ADAAG specifications are targeted at indoor facilities and might not be applicable to all outdoor spaces. According to ADAAG, "letters and numbers on signs shall have a width-to-height ratio between 3:5 and 1:1 and a stroke width-to-height ratio between 1:5 and 1:10" (ADAAG, U.S. Access Board, 1991). MUTCD requirements for size and stroke meet and might even exceed ADAAG specifications. ADAAG Section 4.30 also provides guidelines for character height, raised and brailled characters and pictorial symbol signs, finish and contrast, mounting location and height, and symbols of accessibility.

Pedestrian signs should not be placed in locations where they obstruct the minimum clearance width or protrude into the pathway.

The majority of signs in the public right-of-way are directed at the motorist. Although these signs often affect pedestrians, they are usually not intended for or positioned to be seen by sidewalk users. For example, the street name signs on many large arterials are hung in the center of the intersection. This location is essentially invisible to pedestrians traveling along the sidewalk. Pedestrians might even be put in danger because important safety information, such as yield signage, is not easily visible.

Figure 4-56: Traffic sign indicating upcoming steep grade (US DOT, 1988).

Figure 4-56: Traffic sign indicating upcoming steep grade (US DOT, 1988).

Figure 4-57: Pedestrian sign indicating upcoming steep grade.1

Figure 4-57: Pedestrian sign indicating upcoming steep grade.1

Targeting more signs toward pedestrians would improve safety and permit them to identify routes requiring the least effort for travel. Warning signs similar to standard traffic warning signs (Figure 4-56) would provide information on sidewalk characteristics such as steep grades (Figure 4–57). To date, these types of signs have not been introduced into the MUTCD. Inclusion in this report does not constitute FHWA endorsement. Pedestrian-oriented signage containing access information for trails has been developed as part of the Universal Trail Assessment Process (UTAP) (see Sections 5.1 and 5.4.9). Objective signage provides users with reliable information they can use to make informed choices about their travel routes. In the sidewalk environment, signage should be supplemented with audible or tactile information to be accessible to people with visual impairments.

4.5 Conclusion

Many factors work in concert to make sidewalks and sidewalk elements accessible. Although it is important to make individual features accessible, such improvements will not be useful unless the conditions of the sidewalk as a whole can be negotiated. Accessible sidewalks must be included as part of all new construction and alterations. In addition, regular maintenance programs should be implemented to keep existing routes safe and usable.

Table 4-2.1: Federal Accessibility Guidelines for Accessible Routes

SourceMaximum Allowable Running Grade without HandrailsMaximum Grade with Handrails and Level LandingsMaximum Allowable Running Cross-SlopeMinimum Clearance WidthMaximum Allowable Vertical Change in LevelMinimum Allowable Vertical Clearance(Overhead)
%%m%mmmm
ADA Standards for Accessible Design 1 (US DOJ, 1991) 5.0 28.33 2 9.12.00.915³642.030
UFAS (US DoD, et al., 1984) 5.0 28.33 2 9.12.00.915³642.030

1 The ADA Standards for Accessible Design are identical in content to ADAAG Sections 1-10. However, the Design Standards are enforceable by the U.S. Department of Justice.

2 The ADA Standards for Accessible Design require people to use the least slope possible on accessible routes.

3 Minimum clearance width may be reduced to 0.815 m (32 in) at an obstruction for a maximum length of 0.610 m (24 in).

4 Changes in level between 6 mm (.25 in) and 13 mm (.5 in) are permitted if beveled with a maximum slope of 50 percent.

Table 4-2.2: ADAAG-Proposed Section 14 (1994) Accessibility Guidelines for Public Rights-of-Way

SourceMaximum Allowable Running Grade without HandrailsMaximum Grade with Handrails and Level LandingsMaximum Allowable Running Cross-SlopeMinimum Clearance WidthMaximum Allowable Vertical Change in LevelMinimum Allowable Vertical Clearance(Overhead)
%%m%mmmm
ADAAG-proposed Section 14 (1994)(U.S. Access Board, 1994b) n/a 1n/a n/a2.00.9156 22.030

1 Sidewalk slopes may be consistent with the slope of the adjacent roadway.

2 Changes in level between 6 mm (.25 in) and 13 mm (.5 in) are permitted if beveled with a maximum slope of 50 percent.

Table 4-2.3: State Guidelines for Sidewalks

SourceMaximum Allowable Running Grade without HandrailsMaximum Grade with Handrails and Level LandingsMaximum Allowable Running Cross-SlopeMinimum Clearance WidthMaximum Allowable Vertical Change in LevelMinimum Allowable Vertical Clearance(Overhead)
%%m%mmmm
FL Ped. Planning and Dgn. Guidelines (University of NC Hwy. Safety Research Ctr., 1996) 5.0n/a 1 n/a 12.01.220n/an/a
Oregon Pedestrian Design Guidelines 5.08.33 9.12.01.0n/a2.1
Architectural Barriers Act (Texas Department of Licensing and Regulation, 1997) 5.08.33 9.12.00.9156 22.030

1 Florida directs people to the ADA for maximum grade requirements.

2 Changes in level between 6 mm (.25 in) and 13 mm (.5 in) are permitted if beveled with a maximum slope of 50 percent.

Table 4-2.4: Additional Recommendations for Sidewalks

SourceMaximum Allowable Running Grade without HandrailsMaximum Grade with Handrails and Level LandingsMaximum Allowable Running Cross-SlopeMinimum Clearance WidthMaximum Allowable Vertical Change in LevelMinimum Allowable Vertical Clearance(Overhead)
%%m%mmmm
Accessibility for Elderly and Handicapped Peds. (Earnhart and Simon, 1987) 5.08.33 9.12.00.9156 ¹2.030
ANSI A117.1-1980 (ANSI, 1980) 5.08.33 9.12.00.9156 ¹2.030
ANSI A117.1-1992(Council of American Building Officials,1992) 5.08.33 9.12.10.9156 ¹2.030
Dgn. and Safety of Ped. Facilities (ITE Tech. Council Comm. SA-5, 1998) 8.08.0 9.12.10.915n/an/a

11 Changes in level between 6 mm (.25 in) and 13 mm (.5 in) are permitted if beveled with a maximum slope of 50 percent.

Table 4-3.1: Federal Accessibility Guidelines for Curb Ramps (CR)

SourceMaximum Slope of Curb RampsMaximum Cross-Slope of Curb RampsMaximum Slope of Flared SidesMinimum Ramp WidthMinimum Landing Length
%%%mm
ADA Standards for Accessible Design ¹ (US DOJ, 1991) 8.332, 32.010.04, 50.91560.915
UFAS (US DoD, et al., 1984) 8.332, 32.010.04, 50.91560.915

1 The ADA Standards for Accessible Design are identical in content to ADAAG Sections 1–10. However, the Design Standards are enforceable by the U.S. Department of Justice.

2 The ADA Standards for Accessible Design require people to use the least slope possible on curb ramps that are part of accessible routes.

3 If space prohibits a slope less than 8.33%, curb ramps to be constructed on existing sites may have a slope of 8.33% to 10% with a maximum rise of 150 mm (6 in) or a slope of 10% to 12.5% with a maximum rise of 75 mm (3 in).

4 The flare guidelines do not apply if the curb ramp is located where a pedestrian does not have to walk across the ramp or if the flared sides are protected by handrails or guardrails.

5 If the landing is less than 1.220 m long, the slope of the flared sides must not exceed 8.33%.

6 Exclusive of flared sides.

Table 4-3.2: ADAAG-Proposed Section 14 (1994) Accessibility Guidelines for Curb Ramps (CR)

SourceMaximum Slope of Curb RampsMaximum Cross-Slope of Curb RampsMaximum Slope of Flared SidesMinimum Ramp WidthMinimum Landing Length
%%%mm
ADAAG-Proposed Section 14 (1994)(U.S. Access Board, 1994b) 8.331, 22.010.030.91540.9155

1 The U.S. Access Board recommends using the least slope possible.

2 The slope of a parallel curb ramp should not exceed 8.33%, but is not expected to exceed 2.440 m in length.

3 The flare guidelines do not apply if the curb ramp is located where a pedestrian does not have to walk across the ramp or if the flared sides are protected by handrails or guardrails.

4 Exclusive of flared sides.

5 The minimum allowable landing length is 0.915 m for parallel curb ramps and 1.220 m for perpendicular curb ramps.

Table 4-3.3: State and City Guidelines for Curb Ramps (CR)

SourceMaximum Slope of Curb RampsMaximum Cross-Slope of Curb RampsMaximum Slope of Flared SidesMinimum Ramp WidthMinimum Landing Length
%%%mm
FL Ped. Planning and Dgn. Guidelines (University of NC Hwy.Safety Research Ctr., 1996) 8.33n/a8.3311.01.220
Ped. Compatibility Planning and Dgn. Guidelines (NJ DOT, 1996) 8.33²2.0²10.011.2201.220
Ped. Dgn. Guide (City of Portland, 1997) 8.332.0n/a0.9151.220
Architectural Barriers Act (Texas Department of Licensing and Regulation, 1997) 8.332, 32.010.01, 40.91550.915

1 The flare guidelines do not apply if the curb ramp is located where a pedestrian does not have to walk across the ramp or if the flared sides are protected by handrails or guardrails.

2 The least possible slope should be used.

3 If space prohibits a slope less than 8.33%, curb ramps to be constructed on existing sites may have a slope of 8.33 to 10% with a maximum rise of 150 mm (6 in) or a slope of 10 to 12.5% with a maximum rise of 75 mm (3 in).

4 If the landing is less than 1.220 m long, the slope of the flared sides must not exceed 8.33%.

5 Exclusive of flared sides.

Table 4-3.4: Additional Recommendations for Curb Ramps (CR)

SourceMaximum Slope of Curb RampsMaximum Cross-Slope of Curb RampsMaximum Slope of Flared SidesMinimum Ramp WidthMinimum Landing Length
%%%mm
Accessibility for Elderly and Handicapped Peds.(Earnhart and Simon, 1987) 8.331n/a10.02, 30.915n/a
ANSI A117.1-1980 (ANSI, 1980) 8.331, 42.010.020.91550.915
ANSI A117.1-1992 (Council of American Building Officials, 1992) 8.331, 42.110.020.91550.915
Dgn. and Safety of Ped. Fac. (ITE Tech Council Comm SA-5, 1998) 8.33n/a10.00.915n/a
Planning Dgn. and Maintenance of Ped. Facilities (Bowman, Fruin, and Zegeer, 1989) 8.331n/a10.02, 30.9156n/a

1 If space prohibits a slope less than 8.33%, curb ramps to be constructed on existing sites may have a slope of 8.33 to 10% with a maximum rise of 150 mm (6 in) or a slope of 10% to 12.5% with a maximum rise of 75 mm (3 in).

2 The flare guidelines to not apply if the curb ramp is located where a pedestrian does not have to walk across the ramp or if the flared sides are protected by handrails or guardrails.

3 If the landing is less than 1.220 m long, the slope of the flared sides must not exceed 8.33%.

4 The least possible slope should be used.

5 Exclusive of flared sides.

6 In areas with snow removal, 1.220 m is the minimum recommended ramp width.

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