Figure 2-1: Wheelchair and scooter dimensions (in mm) (based on Architecture and Engineering for Parks Canada and Public Works and Government Services Canada, 1994).

Figure 2-2: Circle diameter of a standard manual wheelchair [ADAAG, Figure 4.3(a), U.S. Access Board, 1991].

Figure 2-3: High and low side-reach limits (Barrier Free Environments, Inc., 1996).

Figure 2-4: Maximum side-reach over an obstruction [ADAAG, Figure 4.6(c), U.S. Access Board, 1991].

Figure 2-5: High and low forward-reach limits (Barrier Free Environments, Inc., 1996).

Figure 2-6: Maximum forward-reach over an obstruction (PLAE, Inc., 1993).

Figure 3-1: Sources of input during the project development process (based on FHWA, 1997a).

Figure 4-1: Maximum grades can make a sidewalk difficult to traverse, even if the overall running grade is moderate.

Figure 4-2: The gutter slopes counter to the slope of the curb ramp to promote drainage.

Figure 4-3: Excessive slope differences between gutter and ramp can cause a wheelchair to tip forward.

Figure 4-4: Excessive slope differences between a gutter and a ramp can cause wheelchairs to flip over backward.

Figure 4-5: Ramps must have level landings (based on ADAAG Figure 16, U.S. Access Board, 1991).

Figure 4-6: When cross-slopes change rapidly over a short distance, wheelchair use becomes extremely unstable.

Figure 4-7: Most pedestrians prefer to travel in the center of the sidewalk.

Figure 4-8: Passing spaces should be included at intervals on narrow sidewalks to allow wheelchair users to pass one another.

Figure 4-9: Wheelchair users require 1.525 m x 1.525 m (60 in x 60 in) to maneuver in a complete circle.

Figure 4-10: Changes in level are often caused by tree roots that break through the sidewalk surface.

Figure 4-11: Vertical and beveled changes in level [ADAAG, Figure 7(c, d), U.S. Access Board, 1991].

Figure 4-12: Wheelchair casters and cane and crutch tips can easily get caught in wide grates.

Figure 4-13: Obstacles mounted on posts should not protrude more than 0.305 m (12 in) into a circulation corridor [ADAAG, Figure 8(d), U.S. Access Board, 1991].

Figure 4-14: Components of a curb ramp.

Figure 4-15: Alternative slope profiles for alterations when an 8.33 percent slope is not achievable.

Figure 4-16: This wheelchair user is maneuvering successfully at a curb ramp because a level landing is provided.

Figure 4-17: This wheelchair user will have difficulty entering the sidewalk because the curb ramp lacks a landing.

Figure 4-18: This wheelchair user will have difficulty traveling around the corner because the curb ramp lacks a landing.

Figure 4-19: Flares provide a sloped transition between the ramp and the surrounding sidewalk and are designed to prevent ambulatory pedestrians from tripping.

Figure 4-20: Returned curbs may be used when the curb ramp is located outside the pedestrian walkway, such as in a planting strip.

Figure 4-21: Without level landings, perpendicular curb ramps are problematic for wheelchair users and others to travel across.

Figure 4-22: Two perpendicular curb ramps with level landings maximize access for pedestrians at intersections.

Figure 4-23: If diagonal curb ramps are installed, a 1.220-m (48-in) clear space should be provided to allow wheelchair users enough room to maneuver into the crosswalk.

Figure 4-24: Parallel curb ramps work well on narrow sidewalks but require users continuing on the pathway to negotiate two ramp grades.

Figure 4-25: A combination curb ramp is a creative way to avoid steep curb ramps and still provide level landings.

Figure 4-26: Built-up curb ramp with drainage inlets.

Figure 4-27: Built-up curb ramp with a drainage pipe.

Figure 4-28: To avoid having to negotiate changing grades and changing cross-slope simultaneously, a wheelchair user has to turn at the grade transition.

Figure 4-29: Curb ramps designed with the ramp perpendicular to the curb eliminate rapidly changing grades and cross-slopes at the grade transition.

Figure 4-30: Truncated domes are an effective way of indicating a drop-off at transit platform.

Figure 4-31: Colored stone sidewalks with concrete curb ramps have a detectable color change.

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 4-34: 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 4-36: 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 4-38: Improved accessibility created by combining parking lots and reducing the number of entrances and exits.

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 4-41: 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 4-43: Diagonal markings enhance visibility.

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

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 4-47: Partial 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 4-50: 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 4-52: 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 4-54: A level area at least 0.915 m (36 in) wide improves access when there is a low street elevation and high finished-floor 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 4-56: Traffic sign indicating upcoming steep grade (US DOT, 1988).

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

Figure 5-1: Outdoor recreation access routes (ORARs) link accessible elements at a recreation site.

Figure 5-2: Trails often have maximum grades that are significantly steeper than typical running grades.

Figure 5-3: Well-designed switchbacks reduce the grade of a trail and make hiking easier for people with mobility disabilities.

Figure 5-4: Rest areas enhance the trail for all users.

Figure 5-5: Tree roots that break up the surface of the trail should be removed because they can cause users to trip.

Figure 5-6: The vertical clearance of a trail should depend on the designated user groups.

Figure 5-7: Soft surfaces are difficult for people with mobility impairments to negotiate and therefore should be avoided.

Figure 5-8: If a trail is accessible, the trail elements along the path also should be accessible.

Figure 5-9: Rubber waterbars are difficult for wheelchair users and bikers to push down when traveling uphill, but they are still more desirable than inflexible waterbars.

Figure 5-10: Swales can control drainage and eliminate the need for waterbars.

Figure 5-11: Separate pathways and clear signage can help reduce conflicts between users who travel at different speeds.

Figure 5-12: Trail signs can help clarify trail etiquette.

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List of Tables

Table 1-1: Developments in Disability Rights Legislation and Accessibility Guidelines from 1961 to 1998

Table 2-1: Highest Reach for Wheelchair Users (based on Steinfeld, Schroeder, and Bishop, 1979)

Table 2-2: Eye-Level Measurements for Wheelchair Users (based on Steinfeld, Schroeder, and Bishop, 1979)

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

Table 4-2.1: Federal Accessibility Guidelines for Accessible Routes

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

Table 4-2.3: State Guidelines for Sidewalks

Table 4-2.4: Additional Recommendations for Sidewalks

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

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

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

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

Table 5-1: Results of 10 Trail Assessments Show That on Many Trails, the Maximum Grade and Cross-Slope Significantly Exceed the Typical Average Grade and Cross-Slope (Chesney and Axelson, 1994)

Table 5-2: Cross-Slope Ranges by Surface Type (AASHTO, 1995)

Table 5-3: Scoping Requirements for Accessible Parking Spaces

Table 5-4.1: Federal Accessibility Guidelines for Maximum Allowable Running Slope without Landings and Handrails

Table 5-4.2: Federal Advisory Committee Recommendations for Maximum Allowable Running Grade

Table 5-4.3: Federal Guidelines for Maximum Allowable Running Grade

Table 5-4.4: State, County, and City Guidelines for Maximum Allowable Running Grade

Table 5-4.5: Additional Recommendations for Maximum Allowable Running Grade

Table 5-5.1: Federal Accessibility Guidelines for Maximum Slope for a Specified Ramp Run with Landings and Handrails

Table 5-5.2: Federal Advisory Committee Recommendations for Maximum Grade for a Specified Distance (Run)

Table 5-5.3: Federal Guidelines for Maximum Grade for a Specified Distance (Run)

Table 5-5.4: State, County, and City Guidelines for Maximum Grade for a Specified Distance (Run)

Table 5-5.5: Additional Recommendations for Maximum Grade for a Specified Distance (Run)

Table 5-6.1: Federal Accessibility Guidelines for Maximum Allowable Running Cross-Slope

Table 5-6.2: Federal Advisory Committee Recommendations for Maximum Allowable Running Cross-Slope

Table 5-6.3: Federal Guidelines for Maximum Allowable Running Cross-Slope

Table 5-6.4: State, County, and City Guidelines for Maximum Allowable Running Cross-Slope

Table 5-6.5: Additional Recommendations for Maximum Allowable Running Cross-Slope

Table 5-7.1: Federal Accessibility Guidelines for Minimum Clearance Width

Table 5-7.2: Federal Advisory Committee Recommendations for Minimum Clearance Width

Table 5-7.3: Federal Guidelines for Minimum Clearance Width

Table 5-7.4: State, County, and City Guidelines for Minimum Clearance Width

Table 5-7.5: Additional Recommendations for Minimum Clearance Width

Table 5-8.1: Federal Accessibility Guidelines for Vertical Changes in Level

Table 5-8.2: Federal Advisory Committee Recommendations for Vertical Changes in Level

Table 5-8.3: Federal Guidelines for Vertical Changes in Level

Table 5-8.4: State, County, and City Guidelines for Vertical Changes in Level

Table 5-8.5: Additional Recommendations for Vertical Changes in Level

Table 5-9.1: Federal Accessibility Guidelines for Vertical Clearance (Head Room)

Table 5-9.2: Federal Advisory Committee Recommendations for Vertical Clearance

Table 5-9.3: Federal Guidelines for Vertical Clearance

Table 5-9.4: State, County, and City Guidelines for Vertical Clearance

Table 5-9.5: Additional Recommendations for Vertical Clearance

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Table of Contents

List of Figures

List of Tables