459788288

Technical report; Sept. 2006-Aug. 2008.

Texas Transportation Institute

NTL-OPERATIONS AND TRAFFIC CONTROLS-Traffic Flow ; NTL-OPERATIONS AND TRAFFIC CONTROLS-Traffic Control DevicesNTL-SAFETY AND SECURITY-Highway Safety ; NTL-SAFETY AND SECURITY-Accidents ;

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In this report, Texas Transportation Institute researchers identify key work zone safety and mobility

performance measures that the Texas Department of Transportation (TxDOT) should target as part of a work

zone monitoring program within a district, region, or across the state. Analysis methodologies and

computational procedures are presented that will yield the recommended performance measures. For

mobility-based measures, researchers recommend that TxDOT target the collection of queue length and

travel time delay data caused by temporary lane closures, as the congestion and delays that result from those

activities are the simplest to isolate and attribute to the work activities themselves.

With regard to work zone safety monitoring, researchers developed procedures that aid a district or project

engineer in determining which projects are most suitable for safety monitoring via a periodic review of crash

statistics occurring before and during the project. Researchers developed graphs that indicate combinations

of work zone length (or work zone segment length), average daily traffic, normal crash rate, and work zone

phase or project direction that will most likely allow for reasonable inferences to be made regarding the

relative level of safety being maintained within the project. Researchers also developed graphs to aid field or

district personnel in quickly determining whether accident frequencies being experienced during a project are

within, or above, tolerance limits for that type of project on that facility.

US Transportation Collection

Project 0-5771