Pedestrians

Pedestrians are accommodated by crossings around the perimeter of the roundabout. By providing space to pause on the splitter island, pedestrians can consider one direction of conflicting traffic at a time, which simplifies the task of crossing the street. The roundabout should be designed to discourage pedestrians from crossing to the central island, e.g., with landscape buffers on the corners. Pedestrian crossings are set back from the yield line by one or more vehicle lengths to:

• Shorten the crossing distance compared to locations adjacent to the inscribed circle;
• Separate vehicle-vehicle and vehicle-pedestrian conflict points; and
• Allow the second entering driver to devote full attention to crossing pedestrians while waiting for the driver ahead to enter the circulatory roadway.

If sidewalks on the intersecting roads are adjacent to the curbs, this setback may require the sidewalks to deviate from a straight path. This is not the case if sidewalks are separated from the curbs by a generous landscape buffer.

Most intersections are two-way stop-controlled, or uncontrolled. Compared to two way stop-controlled intersections, roundabouts may make it easier and safer for pedestrians to cross the major street. At both roundabouts and two-way stop controlled intersections, pedestrians have to judge gaps in the major (uncontrolled) stream of traffic. By reducing stopping distance, the low vehicular speeds through a roundabout generally reduce the frequency and severity of incidents involving pedestrians. In addition, when crossing an exit lane on the minor road, the sight angle is smaller than when watching for left-turning vehicles at a conventional intersecti n.

The comparison between roundabouts and all-way stop-controlled intersections is less clear. All-way stop control is virtually nonexistent in foreign countries that have roundabouts, and so there is little international experience with which to compare. All-way stop-controlled intersections may be preferred by pedestrians with visual impairment because vehicles are required to stop before they enter the intersection. However, crossing the exit leg of an all-way stop-controlled intersection can be intimidating for a pedestrian since traffic may be turning onto the exit from multiple directions. Roundabouts, on the other hand, allow pedestrians to cross one direction of traffic at a time; however, traffic may be moving (albeit at a slow speed), thus making it more challenging to judge gaps, especially for visually impaired users, children, and the elderly.

The biggest difference may be that all-way stop-controlled intersections, like two way stops, do not provide positive geometric features to slow vehicles and instead rely entirely on the authority of the traffic control device. The roundabout geometry physically slows and deflects vehicles, reducing the likelihood of a high-speed collision due to a traffic control device violation.

Signalized intersections offer positive guidance to pedestrians by providing visual and occasionally audible pedestrian signal indications. In this respect, the decision process for pedestrians requires less judgment at signalized intersections than at roundabouts, particularly for visually impaired and elderly pedestrians. However, pedestrians are still vulnerable at signalized intersections to right-turn and left-turn movements unprotected by a green arrow. In addition, high-speed collisions are still possible if a vehicle runs through a red indication. In this respect, the roundabout provides a speed-constrained environment for through traffic. At two-way and all-way stop intersections, right-turning motorists often look only to the left in order to check for vehicular conflicts, endangering or inconveniencing pedestrians crossing from the right or on the right. This situation is exacerbated by the fact that many of these drivers do not come to a complete stop if they do not perceive any conflicts. With crosswalks located back from the circulatory roadway, roundabouts place pedestrians in a more visible location.

The two populations at opposite ends of the age continuum—children and the elderly—and people with disabilities are particularly at risk at intersections. Children (owing to their lack of traffic experience, impulsiveness, and small size) and the elderly (owing to their age-related physical limitations) present challenges to the designer. In recognition of pedestrians with disabilities, intersections must comply with Americans with Disabilities Act (ADA) mandated accessibility standards discussed in Section 2.4.5 and Chapter 5.

Elderly pedestrians, children, and the disabled find it more difficult to cross unprotected road crossings. These types of pedestrians generally prefer larger gaps in the traffic stream, and walk at slower speeds than other pedestrians. Multilane roadways entering and exiting double-lane roundabouts require additional skills to cross, since pedestrians need assurance that they have been seen by drivers in each lane they are crossing.

When crossing a roundabout, there are several areas of difficulty for the blind and or visually impaired pedestrian. It is expected that a visually impaired pedestrian with good travel skills must be able to arrive at an unfamiliar intersection and cross it with pre-existing skills and without special, intersection-specific training. Roundabouts pose problems at several points of the crossing experience, from the perspective of information access.

Unless these issues are addressed by a design, the intersection is “inaccessible” and may not be permissible under the ADA. Chapters 5, 6, and 7 provide specific suggestions to assist in providing the above information. However, more research is required to develop the information jurisdictions need to determine where roundabouts may be appropriate and what design features may be appropriate for the disabled, such as audible signalized crossings. Until specific standards are adopted, engineers and jurisdictions must rely on existing related research and professional judgment to design pedestrian features so that they are usable by pedestrians with disabilities.