Traffic congestion, driver stress, and driver aggression

The stressful characteristics of commuting constraints are conceptualized in terms of both physical and perceptual conditions of travel impedance. This study develops and operationalizes the concept of subjective impedance, as a complement to our previously developed concept of impedance as a physically defined condition of commuting stress. The stress impacts of high-impedance commuting were examined in a study of 79 employees of two companies in the follow-up testing of a longitudinal study. Subjective impedance was overlapping but not isomorphic with physical impedance, and these two dimensions have differential relationships with health and well-being outcomes. The physical impedance construct received further confirmation in validational analyses and in predicted effects on various illness measures and job satisfaction. The newly constructed subjective impedance index was significantly related to evening home mood, residential satisfaction, and chest pain. Job change was also influenced primarily by commuting satisfaction. The results are discussed within an ecological framework emphasizing interdomain transfer effects and situational moderators of commuting stress.