Yes, when a collision does happen, a car is undoubtedly a better place to be, for the same reasons a tank would be better still. However, when it comes to avoiding a collision, in a car one has a whole lot more kinetic energy, and a whole lot less visibility and maneuverability.
In a car one has restraints, a lot of armor to absorb impact, airbags. On a bike you've got ... a helmet.