Guide for Pedestrian and Bicyclist Safety at Alternative and Other Intersections and Interchanges
Alternative
Intersections and Interchanges (A.I.I.s)
are designs that improve operations and safety for motorized traffic by strategically
adjusting the geometric features at a given location, working on the general principle of redistributing
motor vehicle demand at an intersection in an attempt to limit the need to add
capacity with new lanes to improve traffic flow.
The TRB National Cooperative Highway Research Program's
NCHRP Research Report 948:
Guide for Pedestrian and Bicyclist Safety at Alternative and Other Intersections and Interchanges
provides specific guidance for four common A.I.I.s: Diverging Diamond Interchange (DDI), Restricted
Crossing U-Turn (RCUT), Median U-Turn (MUT), and Displaced Left-Turn (DLT).
These designs may involve reversing traffic
lanes from their traditional directions, which may introduce confusion and create safety issues
for pedestrians and bicyclists. In addition, pedestrian paths and bicycle facilities may cross
through islands or take different routes than expected. These new designs are likely to require
additional information for drivers, bicyclists, and pedestrians as well as better accommodations
for pedestrians and bicyclists, including pedestrians with disabilities.
NCHRP 20-44(35) is the implementation project for
NCHRP Research Report 948. The implementation project's objective is to share and disseminate the research results with public agencies and provide hands-on technology transfer assistance to these agencies. Find project outcomes, including webinars and training materials, on
the implementation project page.
This Summary Last Modified On: 1/13/2023