The effects of traffic flow rates at freeway work zones on asphalt pavement construction productivity

Highway work zones reduce available lanes for traffic, leading to traffic delays that can impede the access of material delivery trucks to highway construction sites. This paper analyzes the effects of traffic delays at freeway work zones on asphalt pavement construction productivity. In order to analyze these effects, the values of traffic capacity, vehicle speed and flow rate at work zones were determined. Delay equations were developed to estimate traffic delays when arrival traffic flow was above the work zone capacity and below it. To demonstrate the effects of work zone traffic flows on the cycle times of construction trucks, the traffic flow rates during a 24-hour period at a freeway crossover work zone in Indiana were used. Results show that traffic delays can cause significant increases in the cycle times, which consequently cause considerable reductions in asphalt pavement construction productivity and result in an unbalanced construction condition. To rebalance the construction activities, additional trucks for material delivery must be utilized to compensate for the production losses due to traffic delays. Since vehicle queue lengths are higher during peak periods, a construction firm may need to use different numbers of trucks at different time periods to keep the construction process balanced.