Characteristics of Emerging Road and Trail Users and Their Safety

Station 4-Acceleration

The acceleration rate is defined as the time that it takes for a user to accelerate from a stopped position to a normal cruising speed. Practitioners use acceleration rates to calculate gap acceptance and the necessary intersection sight distance. This is especially important at intersections of shared use paths and roadways where path users are stopped and waiting to cross the roadway. Path users must correctly judge whether gaps in oncoming traffic provide sufficient time to cross the roadway safely, based on the speed of oncoming motor vehicles, their own acceleration capabilities, and the width of the roadway to be crossed.

Figure 34. Participants accelerated along a 60-m (200-ft) section of the course.

Acceleration capabilities were measured for active participants. The acceleration data were collected using time-stamped video to determine the elapsed time for the participants accelerating along a 61-m (200-ft) section of the course (figure 34). This section was further subdivided into lines at 12.2-m (40-ft) spacings. Participants were asked to accelerate to their normal running speed (figures 35 and 36). The time when each participant crossed each transverse line was recorded.

Figure 35. Participants were asked to accelerate to their normal speed.

Figure 36. A skateboarder starting to accelerate.