Anyone who's had the misfortune of being caught in a flood or a sinking vehicle knows how absolutely terrifying it can be. Escaping in such situations isn't easy, and the Australasian New Car Assessment Programme (ANCAP) hopes to shine some light on the subject with an underwater safety rating for new cars.

Starting in 2023, ANCAP will include submergence testing as part of its overall new car rating system. It will be grouped with other ratings in ANCAP's system that explore vehicle accessibility after a crash, focusing on rescuing occupants trapped inside. According to the Australian website CarExpert, manufacturers must show that doors can be opened for at least 10 minutes underwater without battery power, and that electric windows can still function.

Failing these measures, manufacturers must provide occupants a method to open or break the side windows, with information about it all included in the owner's manual. Without these steps, new vehicles from 2023 forward won't be eligible for a maximum ANCAP safety rating.

While there is no specific mention of the reason for this new criteria, ANCAP does mention recent weather events that have caused severe flooding. Beyond that, there's no question that new vehicles are getting ever more complex with electronic systems. That includes power-operated doors and door handles on some vehicles, and information on how such systems work in a flood situation is certainly hard to come by.

Studies have shown that pressure differences between the interior and exterior of a sinking car can prevent doors from opening until the pressure equalises. Unfortunately, the equalisation comes when the cabin fills with water, leaving occupants very little time to escape. It's unclear if or how ANCAP's submergence rating accounts for this condition.