Traffic Control Management Through Construction Zones

As I-70 construction activities in Colorado’s Glenwood Canyon intensified, it became increasingly clear that traditional approaches to construction traffic control could neither efficiently nor safely accommodate existing traffic volumes under the number of active construction projects that would be required to complete the canyon project on schedule. In 1984 and early 1985, traffic-handling conditions had deteriorated to the point where total loss of control was imminent and there was growing public dissatisfaction with the frequently unnecessary and indiscriminate delays. In response, the Colorado Department of Highways (CDOH) authorized its management consultant, Daniel, Mann, Johnson, & Mendenhall (DMJM), to conduct a comprehensive analysis of traffic operations and safety throughout the canyon. The comprehensive study addressed many issues and suggested an innovative approach for handling traffic that would minimize delays, decrease the potential for a complete stoppage in the canyon, and allow control to be regained. Key elements of the proposed traffic management plan included a pilot-car operation, a sophisticated communications network, a systems approach to coordinating all flagging operations, and an umbrella contract that would combine all traffic control functions in the canyon under one separate authority. CDOH authorized a test of the pilot-car operation in late April 1985, which was to continue for an indefinite period of time. Operating through three active construction projects, with combined project limits of 3.6 mi, the pilot-car operation was highly successful and the benefits became immediately obvious. Because the test was conducted initially during a month with a relatively low traffic volume, it was necessary to gain a complete understanding of the dynamics of the pilot-car operation in order to assess its ability of cope with peak summer traffic volumes. Consequently, during the initial test and in subsequent periods, a large amount of operational data was collected. After data reduction and analysis, a complete understanding was gained of the traffic flow characteristics through the construction zones.