Strategy A2. Implement Driveway Turn Restrictions
NCHRP Report 500 / Volume 5: A Guide for Addressing Unsignalized Intersection Collisions
WHERE TO USE:
Driveways located near unsignalized intersections that experience high crash frequencies but that cannot practically be closed or relocated.
When a driveway on a high-volume street adjacent to an unsignalized intersection cannot be closed or relocated, it may be appropriate to restrict turning maneuvers at the driveway. For example, left turns at the driveway can be restricted and driveway movements limited to right turns in and right turns out. In other cases, turning movements into a property may be permitted at a particular driveway, but turning movements out of the property may be diverted to a different driveway. Furthermore, driveway usage may be restricted at particularly critical times of the day. Such restrictions can be implemented by signing, channelizing islands, redesigning the internal circulation patterns within a property, installing a median on the major street, or a combination of these approaches.
KEY TO SUCCESS
Agencies should work with owners of adjacent properties to assure them that some restriction of access to their properties will improve safety and will not affect their ability (or, in the case of a retail business, their customers' ability) to reach their properties. Where practical, these strategies should be implemented as part of a comprehensive corridor access management plan.
Access restrictions could cause some owners of retail businesses to lose (or think they will lose) customers. This is highly dependent upon the type of business and the nature of the access restriction. Such impacts need to be carefully considered by highway agencies in implementing projects. It is advisable to involve stakeholders at the early stages of planning for these improvements.
TIME FRAME: ShortThe time to implement this strategy can range from 3 months to 4 years. Turn restrictions implemented by signing alone can be implemented very quickly when the adjacent property owner is agreeable. Where changes in driveway channelization or internal circulation patterns are involved or where the property owner does not agree with the proposed change, additional time may be required. Where a median is to be installed on the major street, particularly if right-of-way acquisition is required, up to 4 years may be required for the project development process and construction of the improvement.
Costs may be highly variable. Note that compensation is generally not owed to property owners for loss of direct left-turn access.
TRIED: Further evaluations are needed to quantify the safety effectiveness of this strategy. Some of the states that have implemented access management policies include: Iowa, Minnesota, and Florida.
This strategy can be used in conjunction with most other strategies for improving safety at unsignalized intersections and, in particular, those strategies discussed in A1 (Driveway Closures/Relocations).
Highway agencies should establish formal access management policies to guide the planning and permitting process and to provide a basis for remedial treatments at existing locations where driveway-related safety problems occur. For more information on access management, visit: www.accessmanagement.gov.
For more details on this and other countermeasures: http://safety.transportation.org
For more information contact:
FHWA Office of Safety Design
FHWA Resource Center – Safety and Design Team
How to drive a roundabout (WSDOT)