Sweep Width
The AASHTO Guide for the Development of Bicycle Facilities (pg. 22) recommends a minimum width for bike lanes as 1.2 m (4 ft).(2) Additionally it recommends (pp. 35-36) a minimum width of 3 m (10 ft) for a two-way shared use path (and a wider path is desirable where there is substantial use and/or a steep grade), notwithstanding the procedures given in the Highway Capacity Manual for calculating the number and effects of passing events.(26) In other words, the AASHTO recommendation does not explicitly account for user volumes or passing hindrance resulting from user encounters or overtaking/passing events.
The sweep width was measured as each user traveled through an 8-m (26-ft) section of the course (figure 32). Table 17 shows that the mean max sweep width for bicyclists is 1.0 m (3.3 ft). The 85th percentile max sweep width was 1.2 m (4.0 ft). Hence, the AASHTO values of 1.2 m (4 ft) for bike lanes and 3 m (10 ft) for a two-way shared use path accommodates most users traveling single-file in opposite directions to pass each other, though some only barely.
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.
26. Transportation Research Board. Highway Capacity Manual 2000. Transportation Research Board, National Academy of Sciences, Washington, DC, 2000.
Table 17. Sweep width (lateral operating space).
| USER TYPE | N | MEAN MAX (m) | STD DEV MAX (m) | 85TH PER MAX (m) | 95TH PER MAX (m) |
|---|---|---|---|---|---|
| Adult tricycle | 4 | 1.0 | 0.1 | 1.0 | 1.1 |
| Bicycle | 501 | 1.0 | 0.3 | 1.2 | 1.4 |
| Bicycle trailer | 6 | 1.1 | 0.2 | 1.2 | 1.3 |
| Hand cycle | 48 | 0.8 | 0.1 | 1.0 | 1.1 |
| Inline skates | 62 | 1.3 | 0.2 | 1.5 | 1.7 |
| Kick scooter | 28 | 0.9 | 0.2 | 1.1 | 1.2 |
| Manual wheelchair | 15 | 1.1 | 0.4 | 1.5 | 1.8 |
| Pedestrian | 63 | 1.0 | 0.5 | 1.3 | 1.7 |
| Power scooter | 1 | 0.7 | NA | 0.7 | 0.7 |
| Power wheelchair | 12 | 0.8 | 0.2 | 0.9 | 1.1 |
| Recumbent bicycle | 22 | 0.9 | 0.1 | 1.1 | 1.1 |
| Segway | 8 | 1.0 | 0.3 | 1.1 | 1.5 |
| Skateboard | 11 | 1.1 | 0.6 | 1.2 | 2.0 |
| Stroller | 10 | 1.0 | 0.4 | 1.1 | 1.6 |
| Tandem | 3 | 0.9 | 0.0 | 0.9 | 0.9 |
| Other | 17 | 1.2 | 0.3 | 1.5 | 1.7 |
NOTES:
1.This table includes both active and in situ participants.
2.AASHTO value for an on-street bike lane = 1.2 m (4 ft)
3.AASHTO value for a two-way shared use path = 3 m (10 ft)
4.NA = Not applicable because N=1.
Among equipment types with five or more users, inline skates appear to be the critical user. Their mean max sweep width was 1.3 m (4.1 ft), and 85th percentile, 1.5 m (5.0 ft). For all user types, the 85th percentile width was 1.5 m (5 ft) or less. This width slightly exceeds the AASHTO value of 1.2 m (4 ft) for bike lanes. However, the recommended 3 m (10 ft) minimum width for shared use paths is sufficient to accommodate more than 85 percent of the observed individuals within each user type, assuming a two-directional steady linear flow of users traveling single-file on a shared use path.
Section 4.2.2 of the ADAAG requires that the minimum width for two wheelchairs to pass is 1.525 m (60 inches). This assumes that both wheelchair users are traveling in parallel paths to each other and to the edges of the path.
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