This driving simulator study aimed to investigate (1) effects of peer passengers on a variety of risky driving measures, and (2) moderating effects of inhibitory control on these peer passenger effects. Two age groups (n = 30, 17-18 year-olds; n = 20, 21-24 year-olds) participated. Each participant completed two 28km test-drives in a medium-fidelity driving simulator. In the first drive, partic...