In this cross-sectional study, the authors evaluated urinary 1-hydroxypyrene-glucuronide (1-OHP-gluc) as a potential biomarker of exposure to various traffic exhausts. Subjects were 47 female highway toll-station workers and 27 female office workers in training for toll-station employment in Taipei, Taiwan. The mean concentration of urinary 1 -OHP-gluc was 0.117 micromol/mol creatinine in the exposed group and 0.073 micromol/mol creatinine in the reference group (difference in mean concentrations: 0.044 micromol/mol creatinine [95% confidence interval [CI]: 0.015, 0.072). In the lanes where tolls were collected from passenger cars, there was a significant relationship between cumulative traffic and 1-OHP-gluc concentration (i.e., average increase of 0.015 micromol/mol creatinine [95% CI: 0.003, 0.027] per 1,000 vehicles). The average increase for truck/bus lanes was similar to that identified for the car lanes (i.e., average increase of 0.011 micromol/mol creatinine [95% Cl: -0.024, 0.045] per 1,000 vehicles). The authors determined that exposure to various traffic exhausts increased the urinary concentration of 1-OHP-gluc in a dose-response pattern, which suggests that this chemical may be a useful biomarker for exposure to vehicle exhausts.