Sidewalks

Access

For circulation of all pedestrians, the width without obstacles (clear width), grade, and surface quality of sidewalks are considered.

For an average person, the required clear width for standing is 1.5 to 2 feet, and for walking comfortably, it is 3 to 4 feet. For two people walking side-by-side, 5 feet of unobstructed width is required. For wheelchair access, 3 feet of unobstructed width is required on a public right-of-way. If the clear width is less than 5 feet on any route, a passing space with 5 feet of clear width must be provided at reasonable intervals, not exceeding 200 feet. A person with a service animal or a sighted guide uses 4 feet of width. Therefore, accessible sidewalks are a minimum of 5 feet wide on local streets in residential and commercial areas. In central business districts, the width of a sidewalk should be approximately 10 feet.

Grade is the degree of inclination of the slope parallel to the direction of travel. It is the ratio of the change in elevation to the distance covered. A running slope, which is the average slope along a continuous slope, should not exceed 1:20 (5 percent) with ramps not exceeding 1:12 (8.33 percent) where necessary. Cross-slope is the slope measured perpendicular to the direction of travel. It should be measured every 2 feet, which represents the stride of a person or the wheelbase of a wheelchair. The cross-slope of a sidewalk should not exceed 1:50 (2 percent).

The type of surface material on which people circulate is a matter of access, as well. Firm and stable surfaces, such as concrete, are preferable for durability. Slip-resistant surfaces are necessary for safety. Efficiency of movement for pedestrians or for people with disabilities is improved on firm, stable, and slip-resistant surfaces; on such surfaces, people spend their energy mainly for horizontal movement. Changes in level, which refer to the height changes between adjacent surfaces, are problematic for accessibility. Examples of level changes include curbs (without curb ramps), grooves in concrete, heaving, tree root infiltration, and small steps, among many others. Maximum vertical level change is one-quarter inch.

Grates are another example of level changes. A grate is a permeable framework of latticed or [Page 1223]parallel bars allowing liquids and small objects to go through. Maximum width of gaps on a grate is one-half inch in the direction of travel. The maximum gap at a rail flangeway is two and one-half inches.

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