Effect of Freeway Level of Service and Driver Education on Truck Driver Stress: Phase 1

This research primarily deals with truck driver stress and its nature, stressors, and their mutual relationship. During the study, different demands of driving related to roads, vehicle, traffic conditions, driver predisposition to stress, and the surrounding environmental conditions were explored. Two distinct clusters of "Low Stress Level" and "High Stress Level" were identified in the stress distribution. Binary logistic regression was used to relate these two conditions of stress with a wide range of stressors. The results found that truck driver training was a statistically significant factor in predicting low stress level. Other statistically significant factors increasing the likelihood of high stress levels were right turning maneuvers, passive overtaking, and traffic control related factors, such as, the presence of a STOP sign as a control of the intersection. The drivers own disposition to stress highly correlated with stress levels. Driving duration and vehicle parameters, like lateral velocity and co-axial acceleration, were also significant variables in explaining stress levels. The study clearly identified that driver training could lower driving stress level. Additionally, the significance of surrogate factors for level of service, like passive overtaking, controls, acceleration and turn maneuvers, also implied that the improvement of Level of Services of Freeway segments and intersections would play an important role in reducing driver stress.