How can we accommodate baby strollers and bicycles on outdoor staircases?

An important consideration in answering this question is the need to keep the staircase compliant with the Americans with Disabilities Act (ADA). ADA specifications and guidelines can be quite stringent and are enforced as a civil rights issue by the U.S. Department of Justice. Consider the design issues involved in complying with ADA while simultaneously accommodating baby strollers and bicycles.

The treads (horizontals) and risers (verticals) of a staircase define its geometry. Typically, the treads of a staircase are 11 to 12 inches deep and the risers are six to seven inches tall. This can result in an effective slope of 50 to 63 percent. The hand railings are typically about 34 inches above the treads, and should be accessible to someone standing on the adjoining tread.

In accordance with ADA criteria, a wheelchair-accessible ramp can be as steep as five percent. However, ramps steeper than 5 percent -- up to a maximum of 8.33 percent (1:12) -- must have flat, 5-foot long plateaus provided after every vertical 30 inches of elevation gain. This results in an effective design maximum of 7.1 percent for a ramp (a 30-inch gain in elevation over a 35-foot horizontal distance). A five percent slope also works well for bicyclists and baby strollers.

A staircase designed to accommodate bicyclists and baby strollers should offer a shallower than normal staircase slope. To achieve this, treads would be 18 to 20 inches deep and risers would be as short as three to four inches, resulting in slopes in the range of 16 to 20 percent. Most bicycle tires (e.g., road and mountain bicycles) could be accommodated by providing a three-inch wide U-shaped channel on the staircase. However, baby strollers have many different wheel configurations that do not lend themselves to U-shaped channels. A baby stroller is better accommodated by providing a pair of sloped, 12-inch wide ramps on the staircase, with a narrow staircase perhaps 15 to 18 inches wide between the ramps.

What about the location of the channel? An inverted channel for bicycle tires can be provided in the center of the railing-side ramp, providing a guidance effect for the bicycle. Then another accessibility compliance issue arises: the staircase treads would be offset from the handrail. The U channel treatment may also be a tripping hazard, particularly for people with disabilities.

An appealing compromise would be a hybrid approach that provides a fully ADA-compliant portion of the staircase as well as a bicycle- and baby stroller-accessible portion. This would require additional empirical data and public input to define standards that comply with the current and draft standards defined in the Americans with Disabilities Act Accessibility Guidelines (ADAAG). For example, data that defines ramp geometry suitable for the majority of baby strollers is needed. There are variations in bicyclists' needs as well: for example, the horizontal offset of the guidance channel from the handrail needed by most bicycles based on factors such as handlebar width, packs and cargo carried on the bike, etc.

In addition to the general public, other stakeholders in this dialogue should include organizations representing persons with disabilities, the American Institute of Architects (AIA), Building Owners and Contractors Association (BOCA), the Association of Pedestrian and Bicycle Professionals (APBP), etc.

For more information:

U.S. Access Board: