Delivery riders (usually e-bike riders employed in the delivery industry), an emerging occupation as a result of the booming of online commerce in China, have attracted social controversies for the prevalence of unsafe riding and high rates of crash involvement. Given their ever-increasing number and stressful working conditions, more attention should be paid to safety issues involving delivery riders. To illuminate the role of working conditions in influencing safety-related risks of delivery riders, this cross-sectional study was conducted among 824 delivery riders, who answered a self-administered questionnaire gathering information about their demographics, working conditions, riding behaviors, and crash involvement. A mixed probit model of the number of crashes involving riders that allowed for hierarchical relationships between the latent variables identified (i.e., time pressure, fatigue, risky riding behaviors) was employed to determine the underlying association between factors surveyed. The results portrayed a picture of worrisome working conditions for delivery riders. Respondents reported an average of 9.1 daily working hours with insufficient rest. Frequent stair climbing, route planning, and disputes with customers also added to their physical and mental workload. The tested model indicated that a heavy workload, feelings of fatigue, as well as risk-taking behaviors all exerted direct and significant impacts on the involvement in crashes, and time pressure as well as several work-related traits affected crash involvement indirectly, through influencing riders feeling of fatigue and riding behaviors. Findings of this study may provide an empirical basis for road safety interventions for delivery riders in China.