TRB Access Management AHB70

Increasing the awareness and use of Access Management

DOC Errata TRB Access Management Manual 2003

February 2004

Table 2-5 of the Access Management Manual contains a typographical error.
This table indicates the accurate data, with revisions highlighted in red. (pdf version – 80K)

TABLE 2-5 Summary of Research on the Effects of Access Management Techniques (13)
Treatment Effects
1. Add continuous TWLTL • 35% reduction in total crashes• 30% decrease in delay

• 30% increase in capacity

2. Add nontraversable median • 35% >55% reduction in total crashes• >30% decrease in delay

• >30% increase in capacity

3. Replace TWLTL with a
nontraversable Median
• 15%-57% reduction in crashes on 4-lane roads• 25%-50% reduction in crashes on 6-lane roads
4. Add a left-turn bay • 25% to 50% reduction in crashes on 4-lane roads• up to 75% reduction in total crashes at unsignalized access

• 25% increase in capacity

5. Type of left-turn improvementa) painted

b) separator or raised divider

• 32% reduction in total crashes• 67% reduction in total crashes
6. Add right-turn bay • 20% reduction in total crashes
•Limit right-turn interference with platooned flow, increased capacity
7. Increase driveway speed from
5 mph to 10 mph
• 50% reduction in delay per maneuver; less exposure time to following vehicles
8. Visual cue at driveways,
driveway illumination
• 42% reduction in crashes
9. Prohibition of on-street parking • 30% increase in traffic flow• 20%-40% reduction in crashes
10. Long signal spacing with
limited access
• 42% reduction in total vehicle-hours of travel• 59% reduction in delay

• 57,500 gallons fuel saved per mile per year


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