NCHRP 17-08 [Completed]
Traffic Barrier and Control Treatments for Restricted Work Zones
| Project Data
||Texas A&M Research Foundation|
||Dr. Hayes E. Ross, Jr.|
Many construction projects require the use of traffic barriers to adequately protect the motoring public and construction workers. Geometric and operational restrictions in these work zones frequently preclude the use of the same design standards for barriers and terminals that normally apply to permanent systems. One common example involves two-lane, two-way bridges where one-half of the bridge is repaired while maintaining alternating one-way traffic in the remaining lane (usually with temporary traffic control signals). The most common method of traffic control is to install a concrete barrier on the bridge approaches and across the bridge to protect the motorists and workers. While this practice normally provides an acceptable measure of safety for motorists and workers, problems occur when an intersecting highway or driveway that cannot be closed exists near the end of the bridge. In this example, and in other restricted situations, there is often inadequate room to install either the barrier runout at the specified flare rate, an impact attenuator, or other terminal treatments meeting the performance standards for permanent barrier systems. The objective of this research was to develop improved end treatments for temporary traffic barriers, traffic control plans, and user guidelines for restricted work-zone situations.
The research was conducted in two phases. The first phase involved (1) identifying types of work-zone situations where standard barrier terminal treatments and traffic control plans cannot be installed because of restricted conditions, (2) formulating a classification scheme for these situations and defining the basic characteristics for each category, (3) development of conceptual designs for barrier terminal and traffic control treatments for each group considering design vehicle, approach speed, barrier flare rate, safety, and roadway geometrics, and (4) evaluation of the safety, traffic capacity, user delay, costs, and ease of implementation for each concept. The second phase involved (1) development of detailed designs for barrier terminal treatments, (2) evaluation of the terminal treatments through full-scale crash tests, and (3) preparation of a user's manual including detailed design drawings for recommended barrier terminal treatments and special traffic control plans, and guidelines for their use.
Status: The final report has been published as NCHRP Report 358.