In Greenwood, Nebraska a portable traffic management system designed to caution drivers of work zone activity and encourage use of alternative routes during periods of congestion increased traffic diversion by 4 percent.

May 2000
Greenwood,Nebraska,United States

Summary Information

This study evaluated the implementation of a portable traffic management system designed to caution drivers of work zone activity and encourage the use of alternative routes during periods of congestion. The system deployed on interstate I-80 in the vicinity Greenwood, Nebraska, used a pole mounted video detection camera and a portable dynamic message sign (DMS) to monitor vehicle speeds and communicate messages to drivers. The camera and DMS were connected using wireless radio. The camera focused on a single lane of merged traffic and traffic speed data was transmitted upstream to the DMS.

The DMS was located nine miles upstream of the work zone and was preset to display two types of messages depending on traffic speeds detected. If only one or two vehicles were traveling less than 25 mi/h in the work zone, then the DMS flashed the following two-phased message: "ROAD WORK AHEAD" / "PLEASE USE CAUTION". If three or more vehicles were traveling less than 25 mi/h, then the DMS displayed the following message for a period of 10 minutes: "DELAYS!! PLEASE USE ALT ROUTE". The diversion point for the alternative route was about one mile downstream of the DMS. Traffic was routed from I-80, to H-31, to Route-6, and back to I-80 downstream of the work zone.

Pneumatic vehicle counter/classifiers were installed 500 and 1500 feet in advance of the work zone lane closure taper in order to collected traffic speed and lane distribution data "with" and "without" the system in operation. During afternoon peak periods, the mainline, the exit ramp, and the DMS were video taped simultaneously to measure traffic volumes at the diversion point. In addition, drivers were interviewed at a rest stop on I-80 located about two miles downstream of the diversion point.

The vehicle counter/classifier data was collected between noon August 18 and midnight August 22, 1999. Video diversion point data were collected on six days between August 19-29, 1999, during afternoon peak periods when the DMS display was most likely to change from the two-phase message (normal conditions) to the one-phase message (congested conditions). The following results were presented in the report.


Speed and Lane Distribution

The "with" and "without" vehicle speed data were not significantly different. The author noted this was not surprising since the overall objective was to encourage the use of alternative routes and not to control speeds. Moreover, the posted messages did not specify the distance between the DMS and the lane closure; therefore, it was unlikely that drivers associated the DMS with the work zone after 7-9 minutes of travel time.

Diversion Point Volumes

During periods of congestion, the DMS alternate route message increased traffic diversion by 4 percent compared to similar conditions without the message.

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Midwest States Smart Work Zone Deployment Initiative: MwSWZDI Technology Evaluations Year One - Chapter 5: Nebraska - Portable Traffic Management System

Author: Maze, T., et al.

Published By: Mid-America Transportation Center, University of Nebraska

Prepared by Iowa State University, The University of Kansas, University of Missouri-Columbia, and the University of Nebraska – Lincoln

Source Date: May 2000



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Goal Areas


Typical Deployment Locations

Rural Areas


smart work zone systems, smart work zone, smart work zones, Smart work zones, workzone, WZ

Benefit ID: 2007-00434