Every year, more than 50 people die (8.5% of the total number of road deaths in the Netherlands) in a submerged vehicle crash (Figure 1). About 70% of them die by drowning, and about 30% either from other causes, such as the impact of the vehicle hitting the water, or from undetermined causes (e.g. if death by drowning could not be determined) (source: Statistics Netherlands, edited by SWOV).[i]
Drowning is a logical cause of death in fatal submerged vehicle crashes. Foreign research also shows that most casualties die by drowning and not from injuries sustained by the impact of their vehicle hitting the water  . Research by Stjernbrandt et al  showed that 92% of the casualties had a MAIS score[ii] of 2 or lower caused by the impact itself. Hammet et al  and Wintemute et al  found that most injuries should not have prevented casualties from escaping. The casualties would most probably have survived if they had not drowned. Yet, it is unclear whether non-life-threatening (head) injuries limited their capacity to escape the vehicle.
Figure 1. Number of fatalities of submerged vehicle crashes in 2010-2019. Source: Statistics Netherlands, edited by SWOV.
[i] Statistics Netherlands base the number of fatalities of submerged vehicle crashes on their causes of death statistics, court proceedings and, up to 2015, also on police crash registration BRON. SWOV expanded this selection with injuries coded T75.1 (injuries caused by drowning and non-fatal submersion) indicated in the causes of death statistics.
[ii] MAIS is an international measure to indicate injury severity. The score can be derived from patients’ injury codes. Examples of MAIS2 injuries are bone fractures and concussion accompanied by unconsciousness.