If car occupants must wear seat belts, why shouldn't cyclists wear helmets?

Cars and seat belts differ from bikes and bicycle helmets in three key ways

Seat belts provide far better protection to car occupants (72% fatality reduction in head-on crashes, for example Crandall, Olson and Sklar, 2001 ) than helmets provide for bicyclists (no proven reduction for fatal or disabling head injuries – BHRF, 1012; BHRF, 1013 ).
Helmet laws, and to a lesser extent helmet promotion, make cycling less safe by discouraging the activity and thereby undercutting safety in numbers. There are no such analogous effects for driving.
By discouraging cycling, helmet laws suppress both the individual and societal health benefits of cycling, both of which are considerable (BHRF, 1015). There is no such analogous effect for driving.

The combination of these three factors not only destroys the attempted analogy, it makes it more likely that bicycle helmet laws will cost lives rather than save them.

References

BHRF, 1012

What evidence is there that cycle helmets save lives?. .

BHRF, 1013

What evidence is there that cycle helmets reduce serious injury? . .

BHRF, 1015

The health benefits of cycling. .

Crandall, Olson and Sklar, 2001

Crandall CS, Olson LM, Sklar DP, 2001. Mortality Reduction with Air Bag and Seat Belt Use in Head-on Passenger Car Collisions. American Journal of Epidemiology 2001;153(30:219-224.

If car occupants must wear seat belts, why shouldn't cyclists wear helmets?

Cars and seat belts differ from bikes and bicycle helmets in three key ways

References

See also