- Published by: Federal Highway Administration (FHWA)
Federal Highway Administration, Access Management in the Vicinity of Intersections, FHWA-SA-10-002, (February 2010)
This technical summary provides an overview of safety considerations in the design, implementation, and management of driveways near traditional intersections in urban, suburban, and rural environments where design considerations can vary as a function of land uses, travel speeds, volumes of traffic by mode (e.g., car, pedestrian, or bicycle), and many other variables. The technical summary provides an overview of access management factors that should be considered for improving safety near intersections in any setting, as well as specific access management considerations and treatments to improve intersection safety in suburban, urban, and rural settings.
Several factors were described as essential for the planning, design, and implementation of access management strategies to promote safety near intersections. These included:
- roadway functional classification
- the functional area of the intersection
- the location and number of driveways and resulting conflict point
- the use of medians
- driveway design
The following seven guidelines were given for consideration in the development and evaluation of access management treatments.
- Locate Driveways on the Appropriate Roadway Functional Classification
- Limiting Driveways within the Functional Area of an Intersection Improves Safety
- Reducing the Number and Types of Conflict Points Created by a Driveway May Reduce Crashes
- Eliminating Left-Turn Movements at Driveways is Beneficial from a Safety Perspective
- Median Treatments Can Impact Safety
- Reducing Driveway Density Reduces Crash Rates
- Properly Designed Driveways Influence Safety and Mobility at the Driveway
The report includes a suburban case study from La Grande, Oregon of a before/after retrofit and safety analysis. The retrofit involved replacing a painted median with a nontraversable median and incorporating a right turn lane. Before the retrofit , the average crash rate was 0.66 crashes per million entering vehicles and after the retrofit the crash rate reduced to an estimated .06 crashes per million entering vehicles.