5. Conflicts Between Shared Path Users

Public comments submitted in response to the ANPRM expressed concern about the risk of collisions between pedestrians who are blind or have low vision and bicyclists who pass them too closely at fast speeds, and at intersections where a shared use path crosses another shared use path or a sidewalk. According to the AASHTO Guide, the 85th percentile speed for recreational bicyclists is 18 miles per hour. See AASHTO Guide, 5.2.4 Design Speed. The comments noted that bicycles are relatively quiet and pedestrians who are blind or have low vision may not be aware when bicyclists are approaching and passing them or crossing their path at intersections. Pedestrians with other disabilities may also have limited awareness of approaching bicyclists. For example, individuals who are deaf or hard of hearing may not be aware of a bicycle approaching from behind even when riders indicate their presence audibly. Individuals with limited mobility who may be alert to bicyclists may find it difficult to move aside in time to avoid collision. The comments recommended that traffic on shared use paths be regulated and strictly enforced in order to protect pedestrians. For example, a comment stated that bicyclists should be required to always yield to pedestrians. The comments also recommended design solutions to avoid conflicts between users, including separate pathways for pedestrians and bicyclists; and detectable warning surfaces at intersections where a shared use path crosses another shared use path or a sidewalk. These design solutions are discussed below.

Separate Pathways for Pedestrians and Bicyclists

An organization representing individuals who are blind and have low-vision stated that "all shared use paths present an unacceptable safety risk to blind or visually impaired pedestrians unless there is a clear separation between pedestrians and other motorized and non-motorized vehicles including bicyclists." The comments noted that path users cannot be expected to always follow the "rules of the road" and suggested that if paths cannot be physically separated that lanes for pedestrians and other users should be marked tactilely. An organization of educators and rehabilitation professionals who work with individuals who are blind suggested that blind pedestrians may have considerable difficulty maintaining the course, particularly on two-directional shared use paths where all users are expected to travel on the right hand side of the path in each direction and bicyclists pass pedestrians and slower moving path users on their left hand side. In addition to the recommendation to physically separate pedestrians and bicyclists, the comments suggested that it may be necessary to separate the two directions of travel within each pathway, particularly on busy paths. The comments, however, acknowledged that determining what volume of users should require two-directional separation would be a challenge.

The AASHTO Guide makes a number of recommendations to minimize conflicts between pedestrians and bicyclists. These recommendations include required sight triangles to ensure that bicyclists have the needed yielding distance to avoid conflicts, and additional width around horizontal curves to allow safe distance between users. See AASHTO 5.2.8, Stopping Sight Distance. The AAHSTO Guide also recommends use of a centerline stripe within a path to provide directional separation and to indicate when passing is permitted. For paths with "extremely heavy volume", the AASHTO Guide recommends two alternatives for segregation of pedestrians and bicyclists. The first option is to provide separate lanes within a single path; pedestrians have a bidirectional lane and bicyclists have two one-directional lanes. Such separation is not recommended unless a minimum path width of 15 feet can be provided (10 feet for bicycles and 5 feet for pedestrians). A second alternative is to physically separate user groups, particularly where the pathway volume is "extremely heavy" and where sites and settings, such as one that constricts the path width, necessitate divergent pathways. Physically separated pathways also are recommended where the origins and destinations of pedestrians and bicyclists differ. The AAHSTO Guide notes that both alternatives (lane separation and physical separation) may not be effective unless the volume of bicycle traffic is sufficient to discourage pedestrians from encroaching into the bicycle lanes and that these solutions will not necessarily be needed for the full length of a shared use path. See AASHTO Guide, 5.2.1 Width and Clearance.

We agree with the comments that physical separation between pedestrians and other users would likely render shared use paths safer for, and more accessible to, individuals with disabilities and others. However, the AASHTO Guide does not recommend physical separation of user groups unless the traffic volume or other considerations make separate pathways necessary. The AASHTO Guide provides little guidance regarding methods for determining the point at which traffic volume or other considerations would justify separation of the pathways. In the absence of any data on which to base such a requirement, we are not proposing to require physically separated pathways for pedestrians and bicyclists. The impact of such a requirement if applied to the full length of all shared use paths would likely result in many not being constructed due to the increased costs associated with more land and the need to engineer and construct two pathways instead of one.

The comments suggested that enhanced signage and warnings, including audible signs and tactile pavement markings would improve the ability of blind pedestrians to remain within their lanes. In Great Britain, tactile pavement markings are used to indicate bicycle and pedestrian lanes. A ladder pattern is used to indicate the start and end of the pedestrian lane; a tramline pattern is used to indicate the start and end of the bicycle lane; and a tactile dividing line is used to indicate the separation between the lanes.3 At least one U.S. manufacturer makes tactile pavement markings for shared use paths. We request comments on whether tactile pavement markings have been used on any shared use paths in the U.S. and the experience with such markings. We also request comments on other design solutions to reduce potential conflicts between pedestrians who are blind or have low vision and bicyclists. Comments should include factors that would make such solutions necessary.

We are considering including an advisory section in the final accessibility guidelines on separate pathways for pedestrians and bicyclists. Advisory sections are not mandatory requirements but provide guidance for entities who want to exceed the minimum requirements for accessible design. We request comments on information to include in the advisory section.

Detectable Warning Surfaces at Shared Use Path Intersections

Detectable warning surfaces consist of small truncated domes that are integral to a walking surface and that are detectable underfoot. The proposed accessibility guidelines for pedestrian facilities in the public right-of-way would require the use of detectable warning surfaces to indicate the boundary between a pedestrian route and a vehicular route where there is a curb ramp or blended transition; and the boundary of passenger boarding platforms at transit stops for buses and rail vehicles and at passenger boarding and alighting areas at sidewalk or street level transit stops for rail vehicles. See R208 and R305.

Because pedestrians who are blind would not be aware of bicyclists approaching from the left or right hand side at intersections, we are considering including a requirement in the final accessibility guidelines to provide detectable warning surfaces where a shared use path intersects another shared use path or a sidewalk to indicate the boundaries where bicyclists may be crossing the intersection. The edge of the detectable warning surface would be installed between 6 inches minimum and 12 inches maximum from the edge of the intersecting segments of the shared use paths and sidewalks. The detectable warning surface would extend 2 feet minimum in the direction of pedestrian travel and the full width of the intersecting segments. We request comments on this issue.