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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
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Publication Number: FHWA-HRT-05-099
Date: July 2006
Federal Highway Administration University Course on Bicycle and Pedestrian Transportation
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LESSON 8: PEDESTRIAN CHARACTERISTICS
A roadway that is designed to accommodate pedestrian use must take into account the wide range of needs and physical capabilities of different pedestrian groups. An agile, able-bodied person can frequently overcome design deficiencies. However, when age or functional disabilities reduce a person’s mobility, sight, or hearing, a good design becomes very important.
This section provides an overview of basic pedestrian characteristics that most often come into effect when designing pedestrian facilities in the public right-of-way. It discusses the walking speeds and space requirements of these various groups and the roadway design elements required to accommodate them. The major sections of this lesson are as follows:
Pedestrian design currently features at least two schools of thought: traditional engineering design and the design of accessible rights-of-way. Traditional engineering employs designs based on minimum cost and maximum efficiency. This premise is decades old and consists of designing roadways for the most likely common user, a specific design vehicle, design hourly volume, etc. For example, a curb radius on a residential street is not large enough to accommodate all vehicles. Large trucks will swing wide into the opposing lane and use both directions on the receiving roadway. Likewise, roadways are built to accommodate a certain design hour traffic that is less than the greatest traffic volume, which often results in congestion during part of the day. The cost to accommodate all vehicles on all facilities is deemed to be cost-prohibitive.
Designing accessible rights-of-way is based on the concept that no one should be discriminated or denied access to public facilities or services. The United States Access Board has developed minimum accessibility standards for certain road design features such as curb ramps and detectable warnings. These design elements are to be provided as a matter of law. However, there are other right-of-way design features for which no enforceable accessibility standards currently exist, such as pedestrian signal timing or roundabouts. Where no enforceable accessibility design standards exist, engineers must make decisions about roadway design that directly affect the users. Advocates for the disabled recommend that roads be designed for all users with disabilities—increasing the accessibility for users with disabilities increases the accessibility for all users. Until enforceable accessibility standards are developed, however, some public agencies will continue traditional design practices that best serve the majority of users to the exclusion of others.
Even with limited resources (right-of-way, environmental, time, etc.), new designs and methods will emerge that attempt to accommodate all users in a safe and efficient manner. This lesson will present both methods so that the reader can decide what is most appropriate at the time. Some of these methods will be addressed by law and some will be addressed by policy.
Regardless of what finally emerges from this debate, currently, new and altered facilities must be designed and constructed to be accessible to and usable by individuals with disabilities; existing facilities and programs must achieve program accessibility. Examples of alterations in rights-of-way construction include roadway realignment or widening, or the addition of a sidewalk along an existing right-of-way. Where additional right-of-way is acquired for a roadway project, it is important to consider accessible sidewalk construction; improved access to adjacent sites and existing facilities should also be considered.
8.2 Characteristics of Different Age Groups
Table 8-1 lists some common characteristics of pedestrians in different age groups. The table was adapted from the Florida Pedestrian Planning and Design Handbook and chapter 2 of the County of Sacramento Pedestrian Design Guidelines.(1,2)
Child pedestrians have important characteristics that separate them from the adult pedestrian population and make them a particular concern for roadway designers. Until the age of about 10 years, children have a limited concept of rules and why they are needed. They often have problems with risk perception, attention, and impulsivity that make them more vulnerable pedestrians. In addition to adult supervision and effective education programs, careful design of the places children walk most, such as school zones and school walking routes, neighborhood streets, and parks, can significantly help to improve their safety.
Children’s comprehension of safety is poorly formulated, and their understanding of critical behaviors, such as crossing the street, are not well developed. This is one among many reasons for the relatively high crash rate among young pedestrians. The following factors also appear to contribute to the child pedestrian problem:(3)
Table 8-1. Walking characteristics and abilities of different pedestrian age groups.
The experiences of older pedestrians are different from that of the young person. In general, they do not behave as irrationally as do many children and young adults. However, older pedestrians often have physical conditions that limit their abilities to accurately assess the traffic situation. Older people also tend to walk more than others because they have more free time, it is good exercise, and it is an inexpensive mode of travel for short trips. The elderly are more law abiding than the general population, and they may in fact be too trusting of traffic signals and of drivers when it comes to crossing the streets. They are more likely than younger pedestrians to be involved in crashes due to problems in information processing, judgment, and physical constraints. Following is a list of other characteristics of older pedestrians:
8.3 Other Pedestrian Types and Characteristics
Table 8-2 lists some other types of pedestrians that can be grouped by their walking characteristics.
Table 8-2. Characteristics of other pedestrian groups.
Mobility-impaired pedestrians include those with wheelchairs, crutches, canes, walkers, guide dogs, prosthetic limbs, orthotics, or other assistive devices. Some may not require these devices but still have a disability that limits their range or speed of motion. Table 8-3 contains a list of design features that help accommodate mobility-impaired pedestrians.(2)
Table 8-3. Design needs of mobility-impaired pedestrians.
8.4 Walking Speeds
Pedestrians have a wide range of needs and abilities. The Manual on Uniform Traffic Control Devices for Streets and Highways (MUTCD) recommends a speed of 1.2 meter/second (m/s) [4.0 feet/second (ft/s)] for calculating pedestrian clearance intervals for traffic signals.(4) It also includes a comment that where pedestrians who walk slower than normal, or pedestrians who use wheelchairs, routinely use the crosswalk, a walking speed of less than 1.2 m/s (4.0 ft/s) should be considered in determining the pedestrian clearance times. Other studies have identified pedestrian walking speeds ranging from 0.6 to 1.3 m/s (2.0 to 4.3 ft/s). The Institute of Transportation Engineers (ITE) publication, Design and Safety of Pedestrian Facilities, even cited walking speeds up to 2.4 m/s (8 ft/s).(5)
By definition, about half of all pedestrians travel at a slower pace than the average walking speed. These slower walking pedestrians include older pedestrians, people with disabilities, and people pushing a baby stroller and/or paying attention to younger children walking alongside (see figure 8-1). Therefore, the slower walking speeds of these groups should be considered when designing pedestrian facilities such as crossing times at intersections.
Figure 8-1. Photo. People with children often walk at slower speeds.
Guidelines and Recommendations to Accommodate Older Drivers and Pedestrians recommends an assumed walking speed of 0.9 m/s (2.8 ft/s) for less capable older pedestrians because of their shorter stride, slower gait, difficulty negotiating curbs, difficulty judging speeds of oncoming vehicles, and exaggerated startup time before leaving the curb (see figure 8-2).(6) Mean startup time (from the start of the Walk signal to the moment the pedestrian steps off the curb and starts to cross) was 2.5 seconds for older pedestrians, compared to 1.9 seconds for younger ones.(3) A study in Sweden found that pedestrians aged 70 or older, when asked to cross an intersection very fast, fast, or at normal speed, considered fast to be less than 1.3 m/s (4.3 ft/s).(7) The comfortable speed for 15 percent of the group was 0.7 m/s (2.2 ft/s), well below the standard often used.
Figure 8-2. Photo. Older pedestrians often have difficulty negotiating curbs.
Pedestrians with Disabilities
According to a study done in the United Kingdom in the 1980s, about 14 percent of adults over 15 years of age had physical, sensory, or mental disabilities.(8) This population has become much more mobile in recent decades, and increasing efforts have been made to meet their transportation needs. As expected, the walking speeds for pedestrians with disabilities are lower than the average walking speed assumed for the design of pedestrian facilities.(3) Table 8-4 shows some average walking speeds for various disabilities and assistive devices.
Table 8-4. Mean walking speeds for disabled pedestrians and users of various assistive devices.
8.5 Space Requirements
A recent study of pedestrian characteristics recommends for standing area design a simplified body ellipse of 50 centimeters (cm) by 59.9 cm (19.7 inch by 23.6 inch) for standing areas, with a total area of 0.3 square meters (m2) (3.2 square feet (ft2)), or roughly 108 percent of the ellipse suggested by Fruin’s 1971 study (see figure 8-3).(9,10) This study also recommends a body buffer zone of 0.8 m2 (8.6 ft2) for walking.
Georgia’s Pedestrian Facilities Guidebook states that two people walking side by side or passing each other while traveling in opposite directions take up an average space of 1.4 m (4.7 ft) with adequate buffer areas on either side (see figure 8-4).(11) The minimum width that best serves two pedestrians walking together or passing each other is 1.8 m (6 ft). More space may be required, such as 2.7–3.9 m (8.7–12.7 ft), to accommodate situations where three or more people are walking abreast.
A spatial bubble is the preferred distance of unobstructed forward vision one experiences while walking under various circumstances.(11) Figure 8-5 illustrates the spatial bubbles that are comfortable for the average pedestrian while attending a public event, shopping, walking under normal conditions, and walking for pleasure.
Pedestrians with Disabilities
Space requirements for pedestrians with disabilities vary considerably depending on the assistive device used. Spaces designed to accommodate wheelchair users are generally considered to be functional and advantageous for most people. Figure 8-6 illustrates the spatial dimensions needed for a wheelchair user, a person on crutches, and a sight-impaired person using the cane technique.
8.6 Design Requirements
Roadways, sidewalks, and intersections that are designed to meet the needs of disabled pedestrians generally benefit all pedestrian movement. Below are some criteria for designing pedestrian facilities to accommodate all types of users.
Two people walking side-by-side or passing one another generally require almost 1.5 m (5 ft) of space, while wheelchair and scooter users need more space in order to pass one another.(2) However, the Americans with Disabilities Act (ADA) states that 1.2 m (4 ft) is the “minimum width needed for an ambulatory person to pass a nonambulatory person.”(12) A clear width of at least 1.5 m (5 ft) is preferred, especially if the area has a high volume of pedestrians with disabilities (see figures 8-7 and 8-8). If the width of the sidewalk is less than 1.5 m (5 ft), two wheelchair users will not be able to pass each other and will have to find a wider place for passing. Passing spaces must be located at reasonable intervals not to exceed 61 m (200 ft). ADA requirements “specify a minimum space of 1.5 m (5 ft) in diameter or a 1.5 m (5 ft) by 1.5 m (5 ft) T‑shaped space for a pivoting 180-degree turn of a wheelchair.”(12) A T-intersection of two corridors or walks is an acceptable passing place.
Sidewalks should be built and maintained in urban areas along all major arterial streets, in commercial areas where the public is invited, and at all transit stops and public areas. They should be paved with a smooth, durable material. It is desirable to have paved sidewalks on both sides of all streets in urban and suburban areas to provide mobility for disabled (as well as nondisabled) pedestrians. A planting strip, which serves as a buffer between on-street vehicles and pedestrians on the sidewalk, can be especially beneficial to visually impaired pedestrians on the sidewalk and to wheelchair users. Sidewalks should be kept in good condition, free from debris, cracks, and rough surfaces.
There should be enough sidewalk cross slope to allow for adequate drainage. The maximum cross slope should be no more than 2 percent (1:50) to comply with ADA requirements. A person using crutches or a wheelchair has to exert significantly more effort to maintain a straight course on a sloped surface than on a level surface. Driveway slopes should not encroach into the sidewalk. A 1.8 m (6 ft) setback will generally prevent this encroachment (see figure 8-9).
Several driveway design options are available to maintain the desired cross slope. Placing the sidewalk behind the driveway ramp or using curb ramps and aprons are two methods typically used. A minimum sidewalk width of four feet needs to be maintained regardless of right-of-way constraints. Ramp slopes also need to be adhered to when accommodating driveway crossings.
Figure 8-9. Photo. Driveway slopes should not encroach into the sidewalk.
Where the sidewalk is located adjacent to the street, it should be rerouted sufficiently away from the street (to the back of the right‑of‑way or on an easement, if necessary), out of the driveway slope.
Longitudinal grades on sidewalks should be limited to 5 percent. If a sidewalk is adjacent to a roadway with a grade exceeding 5 percent, the sidewalk grade must be less than or equal to the grade of the roadway. A pedestrian facility that is not along a roadway should have less than 5 percent grade but may be a maximum of 1:12 (8.3 percent), if hand rails and landings are provided.(13) Long, steep grades should have level areas at intermittent distances (every 9.1 m (30 ft)), since traversing a steep slope with crutches, artificial limbs, or in a wheelchair is difficult and level areas are needed for the pedestrian to stop and rest. If there are areas where it is impossible to avoid steep grades, an alternative route (such as an elevator in a nearby building) should be provided. However, ADA does not require accommodations in all locations where natural terrain prevents treatment.
Where grades exceed 5 percent, special textures and handrails may be required. Handrails are used by persons in wheelchairs to help pull themselves up and are used by other persons for support. Informational signs, indicating alternative routes or facilities, can be placed at the base of the grade or in a guidebook for the area. Arrangements may be made with the local transit authorities to transport persons with disabilities at a reduced (or no) fare where steep grades or other obstacles prohibit or severely impede access.
Street furniture, such as benches and bus shelters, should be out of the normal travel path to the extent possible. For greater conspicuity, high-contrast colors, such as red, yellow, and black, are preferable. The following guidelines should be considered in the positioning of street furniture:
Another common problem for wheelchair users is the placement of street furniture next to on-street parking, which can make exiting a car or lift-equipped vehicle difficult. One remedy is to relocate the street furniture toward the end of the parking space instead of the center, or at the back of the sidewalk furthest from the curb. At least 1.5 m (5 ft) of clear space width along the sidewalk is needed to allow for exiting a vehicle. Other objects, such as streetlight poles, may be more difficult to move, so consideration may be given to relocating the accessible parking space or reserving extra accessible parking spaces.
Some individuals may have difficulty operating pedestrian pushbuttons. In some instances, there may be a need to install a larger pushbutton or to change the placement of the pushbutton. Pedestrian pushbuttons should always be easily accessible to individuals in wheelchairs and should be no more than 1.2 m (4 ft) above the sidewalk (see figures 8-10 and 8-11) to be within the reach limits of wheelchair users. The force required to activate the pushbutton should be no greater than 2.3 kilograms (kg) (5 pounds (lb)).
Pedestrian pushbuttons should be located next to the sidewalk landing, the top of the ramp, and adjacent to the appropriate crosswalk ramp. If there are two pushbuttons at a corner (one for each crosswalk), the pushbuttons should, ideally, be located on separate poles and adjacent to their respective ramps to avoid user confusion.
Curb Cuts and Wheelchair Ramps
The single most important design consideration for persons in wheelchairs is to provide curb cuts. New and rebuilt streets with sidewalks should always have curb cuts at all crosswalks. A roll curb (i.e., one with a sloped rather than a vertical curb face) is a barrier and will not allow for wheelchair access. Curb cuts should be at least 1.2 m (4 ft) wide at the base, exclusive of flared sides (see figures 8-12 and 8-13). The flared sides should not exceed a slope of 1:10 (see figures 8-12 and 8-14) or 1:12 if the sidewalk width in front of the curb ramp is less than 1.2 m (4 ft) wide (see figures 8-14 and 8-15). The least possible slope should be used for the ramp, but the maximum slope of the ramp is 1:12 (see figure 8-13).
However, sometimes there is a constrained right-of-way and not enough space to construct a ramp with these dimensions perpendicular to the roadway. In such cases, a ramp should be built from the roadway surface to a midpoint landing that is as flat as possible, and then the rest of the ramp can be constructed from the landing to the sidewalk parallel to the roadway (see figure 8-16). While this method is not the ideal design choice, it is a workable solution in situations with narrow sidewalk space and a limited right-of-way.
Figure 8-15. Photo. Perpendicular curb ramp..
Figure 8-16. Photo. Parallel curb ramp.
It is desirable to provide two curb cuts per corner. Single ramps located in the center of a corner are less desirable than a separate ramp for each crosswalk to accommodate pedestrians with disabilities and should not be built for newly constructed or reconstructed sidewalks. Separate ramps provide greater information to visually impaired pedestrians in street crossings, especially if the ramp is designed to be parallel to the crosswalk. Diagrams (a) and (b) in figure 8-17 have two curb cuts and ramps per corner, both leading the ramp to the center of the marked crosswalk. Diagrams (c) and (d) have only one cut per corner, which leads the ramp to the center of the intersection and would require a ramp user to turn at the bottom of the ramp in order to face the marked crosswalk. For visually impaired pedestrians, it is beneficial to have a ramp leading directly to the crosswalk, rather than the intersection, to help orient them in the proper crossing direction. These also benefit others with mobility limitations such as elderly pedestrians and persons pushing strollers, carts, etc.
Crosswalk markings should be located so that a pedestrian in a wheelchair should not have to leave the crosswalk to enter or exit the street. In some cases, a wider ramp may be used to accommodate pedestrians in wheelchairs.
The ramps should be flared smooth into the street surface (see figure 8-18). Ramps should be checked periodically to make sure large gaps do not develop between the gutter and street surface. There may be a need to remove accumulations of asphalt at the edge of the curb radius.
Figure 8-18. Photo. A pavement grinding project left an exaggerated lip at this curb cut.
Ramps or cut-through islands should be provided for marked or unmarked crosswalks at median (or frontage road) islands. Cut-throughs should be designed to provide proper drainage and to avoid ponding.
Drainage is important. Standing water can obscure a dropoff or pothole at the base of a ramp and makes the crossing messy. Storm drain inlets should be clear of the crosswalk. If this is not possible, the openings in the grate should be no larger than 1.3 cm (0.5 inch) in width.
8.7 Student Exercise
To help you recognize how challenging visual and mobility impairments can be, shadow a pedestrian with a disability to or from home or work, or travel in a wheelchair and then as a blindfolded pedestrian.
For safety, the following rules apply to this activity:
8.8 References and Additional Resources
The references for this lesson are:
Additional resources for this lesson include: