Summary Road accidents are one of the leading causes of death in the world. They are also one of the main causes of work fatalities. In Québec, although work-related road accidents (WRRAs) are only responsible for 2% of employment injuries, they are the cause of 25 to 30% of accidental deaths at work. Because of severity of the injuries they cause, WRRAs are a particularly costly type of industrial accident. Moreover, they are one of the rare types of industrial accidents that sometimes involve non-occupational injuries, i.e., injuries to people involved in a WRRA but who were not working at the time of the accident. These other victims make the burden associated with WRRAs even heavier. Given this, it is important to analyze the global costs of WRRAs in Québec. As an indicator, cost has the advantage of condensing into a single measurement a considerable share of the consequences and severity of WRRAs, whatever their nature. This study aims not only to contribute to a better understanding of the consequences of WRRAs for Québec society, but also to identify the characteristics and groups of workers associated with the costliest WRRAs. This was made possible by cross referencing data from the Commission des normes, de l’équité, de la santé et de la sécurité du travail (CNESST) and the Société de l’assurance automobile du Québec (SAAQ). CNESST data from 2001 to 2015 identified 20,606 employment injuries related to a WRRA. Their number decreased by 11% over the study period, compared to a 38% decrease for all industrial accidents in Québec. From 2001 to 2015, employment injuries related to a WRRA resulted in an estimated cost of $2.7B. The average cost per injury is estimated at $131,200, i.e., twice the average cost of an employment injury in Québec, for all types of injuries. Only 1.6% of WRRA injuries resulted in death, but they accounted for 42.9% of total costs. The study found that the highest total or average costs do not occur only in industries and to professionals in the transport sector, but in a variety of industries and occupations. These include agriculture, forestry, construction, police officers and ambulance drivers. The analyses also show that accidents involving worker-pedestrians and head-on collisions between vehicles are the costliest types of accidents, both in terms of total costs and the average cost per injury. Data from the SAAQ identified 3497 non-occupational injuries linked to a WRRA over the study period. These injuries were less numerous than employment injuries but appeared to be more serious. In fact, there was a much higher proportion of injuries resulting in death than for employment injuries (11% versus 1.6%). Due to methodological constraints, the costs of non-occupational injuries could only be estimated for 2015. For that year, the 154 non-occupational injuries generated total costs estimated at $71.1 million, or $461,900 per injury. The average cost per injury was four times higher than the average cost of an employment injury related to a WRRA for the same year. Accident analysis is an innovative approach that combines all the recorded injuries (CNESST and SAAQ) related to a single WRRA. This puts the focus on the accidental event, rather than on individual injuries. The 763 WRRAs identified in 2015 resulted in 968 injuries, or 1.27 injuries per accident. The average cost of a WRRA was estimated at $238,800. Data from the SAAQ made it possible to identify the characteristics of the costliest WRRAs, mainly through information from police reports. The two causes of accidents that led to the highest costs were speed and other reckless behaviour, such as inattention, distraction and using a cell phone. A problem with the vehicle, mainly tires not adapted to winter conditions or that were unsafe, is the cause that led to the highest average cost per accident. Higher than average costs per WRRA were observed for WRRAs that involved either a heavy truck/fifth-wheel tractor, a pedestrian or an emergency vehicle (police car, ambulance, fire truck). Head-on collisions and WRRAs occurring in rural areas were also identified as being the costliest, both in terms of total costs and average cost per injury. The results also show the importance of restraint or protective devices (e.g., seatbelts, helmets) on the severity of injuries suffered by WRRA victims. When these devices are absent, not used or misused by any of the injured parties involved in the accident, it results in a very high average cost per WRRA. This study thus contributes to a better understanding of the overall consequences of work-related road accidents in Québec. The study highlights the essential contribution of SAAQ data to the analysis of WRRAs in Québec. These data not only make it possible to better characterize WRRAs, but also to draw a more complete portrait of the consequences of this type of accident, by making it possible to take into account injured people who were not at work at the time of the accident.