Effects of Varying Work Zone Configuration, Distances Between Traffic Signs and Individual Differences on Drivers’ Perceived Workload

This simulation-based study explores the effects of different work zone configurations, varying distances between traffic signs and individual differences on drivers’ perceived workload. Conventional Lane Merge (CLM) and Joint Lane Merge (JLM) were modeled in a driving simulator and thirty participants (seven female and 23 male students), navigated through the two configurations in three different conditions: a) standard sign distance, b) 25% reduction, and c) 25% increase in the distance between traffic signs in the advance warning area. NASA task load index (TLX) was used to measure mental demand; physical demand, temporal demand, performance, effort; frustration and total workload were recorded for. The results of this study indicated that drivers’ self evaluated measure of performance in JLM was 18.8% higher than CLM and driving through JLM required 15.2% less total workload. Moreover, mental demand, temporal demand, effort and frustration were lower in JLM by 16.4%, 23.4%, 13.7% and 28%, respectively. However, increasing or decreasing the distance between traffic signs by 25%, increased the total perceived workload by 4% and 8%, respectively, which suggests that the current distances between traffic signs, prior to work zones, are optimal. Analysis of personal differences indicates that the perceived total workload differs significantly between male (21.2%) and female participants (28.7%), and those who had previous traffic offences experienced 87% less frustration and put 15% less effort to complete the task. Finally, significant correlations were found between driving behavior and perceived workload, indicating that driving behavior is an important predictor of perceived workload.