De l’utilité du casque en cas de collision avec une auto. Et c’est le patron d’un fabricant de casques qui le dit:

However, cyclists should not rely on cycle helmets to offer protection against smashes with cars, trucks, or other large, heavy, and often fast road vehicles.

“There are many misconceptions about helmets,” Richter told British trade magazine Cycling Industry News on July 6.

“We do not design helmets specifically to reduce chances or severity of injury when impacts involve a car,” said Richter.

“The number of variables is too great to calculate.”

These variables include the speed of the motor vehicle, its mass, the angle of impact, and the vehicle’s profile.

In 2016, 50% of the people killed while riding their bicycles in the U.S. were not wearing helmets, which leaves the other half, some of whom may have been wearing helmets but who were still killed after being hit by motorists.

Source: Bicycle Helmets Not Designed For Impacts From Cars, Stresses Leading Maker Giro