Objective Pedestrian injuries are among the most common cause of death and serious injury to children. A range of risk factors, including individual differences and traffic environment factors, has been investigated as predictors of children's pedestrian behaviours. There is little evidence examining how risk factors might interact with each other to influence children's risk, however. The present study examined the independent and joint influences of individual differences (sex and sensation seeking) and traffic environment factors (vehicle speeds and inter-vehicle distances) on children's pedestrian safety. Methods A total of 300 children aged 10-13 years were recruited to complete a sensation-seeking scale, and 120 of those were selected for further evaluation based on having high or low sensation-seeking scores in each gender, with 30 children in each group. Children's pedestrian crossing behaviours were evaluated in a virtual reality traffic environment. Results Children low in sensation seeking missed more opportunities to cross and had longer start gaps to enter the roadway compared with those high in sensation seeking, and these effects were more substantial when vehicles were spread further apart but travelling slowly. Interaction effects between inter-vehicle distance and vehicle speed were also detected, with children engaging in riskier crossings when the car was moving more quickly and the vehicles were spread further than when the vehicles were moving quickly but were closer together. No sex differences or interactions emerged. Conclusion Both sensation seeking and traffic environment factors impact children's behaviour in traffic, and there are interactions between traffic speeds and inter-vehicle distances that impact crossing behaviour.