Characteristics of Emerging Road and Trail Users and Their Safety

Length

The AASHTO Guide for the Development of Bicycle Facilities (p. 65) incorporates a bicycle length of 180 cm (72 inches) in its calculations for recommended traffic signal timing.⁽²⁾ Table 8 shows that the mean length for bicycles was 168 cm (66 inches), and the 85^th percentile, 178 cm (70 inches). In other words, 85 percent of observed bicycles had lengths of 178 cm (70 inches) or less. Thus, the values observed for bicycles in particular seem to be consistent with the AASHTO value.

Among equipment types with five or more users, recumbent bicycles appear to be the critical user, as they had the highest mean (190 cm (75 inches)) and 85th percentile (208 cm (82 inches)) lengths. The 85^th percentile length of hand cycles also exceeded 180 cm (72 inches). Although only four bicycles with trailers were observed in this study, they had a mean length of 290 cm (114 inches) and an 85^th percentile length of 296 cm (117 inches). Thus, the AASHTO value is not sufficiently long for these user types, with potentially serious consequences-see "Refuge Island" in the "Discussion" section of this report.

^2. American Association of State Highway and Transportation Officials. Guide for the Development of Bicycle Facilities. American Association of State Highway and Transportation Officials, Washington, DC, 1999.

Table 8. Length.

NOTES:
1. This table includes only active participants.
2. AASHTO value for bicyclists = 180 cm (72 inches)
3. The lengths for inline skaters are their rest lengths. Their lengths while in motion will vary depending on where they are in their stride.
4. NA = Not applicable because N=1.