Forty-six bus drivers took part in a longitudinal field study of cardiovasc
ular reactions to urban driving. "Job hassles" were recorded by observers u
sing a standardized list of stress-related events in traffic and on the bus
. Measures of blood pressure, heart rate, and ratings of perceived mental s
train were obtained after each route segment. Intraindividual correlations
between psychophysiological recordings and job hassles were calculated and
submitted to cluster analysis. Two reaction patterns were identified, 1 cha
racterized by consistently, although modestly, positive associations betwee
n the frequency of job hassles and psychophysiological reactions, the other
characterized by a low association between the frequency of hassles and in
dicators of psychophysiological arousal. The former group displayed signifi
cantly higher blood pressure and mental strain ratings in the unwinding pha
se after work than did the latter group of workers. The results are discuss
ed in terms of rate of "unwinding" after exposure to stressful conditions.