Impacts of Construction Work Zone Equipment and Operations on Vehicle Speeds

Mobile construction operations that are conducted at night and do not employ positive barrier systems present significant safety hazards for workers and motorists. As part of several research studies on the effectiveness of traffic control devices to enhance work zone safety, the authors investigated the impacts of construction equipment and operations on safety and exposed how a contractor could use the construction operations advantageously to benefit work zone safety. Five preservation (re-paving) projects on high-speed roadways were selected for data collection. On each project, traffic speeds were recorded prior to and at multiple points within the work zones while the work was conducted. The results reveal that the presence of large construction equipment in the work area impacts driver speed. Vehicles begin to slow down approximately 0.2 to 0.6 mi. before reaching the paver, and then increase over approximately the same distance after the paver. The amount of decrease in speed ranged from approximately 5 to 25 mph. In addition, the lateral distance between vehicles and construction equipment was also found to impact vehicle speeds. The findings reveal that contractors can utilize the presence of equipment and strategically-planned operations to benefit safety in work zones. While the findings are applicable to mobile construction operations on high-speed roadways, it is expected that equipment could be used and operations planned strategically on other types of projects, such as building projects, to benefit safety in a similar manner.