[vikingerik]

There is data to this effect for bike helmets, that the feeling of safety induces more risky behavior. Helmeted riders act more aggressively near both cars and pedestrians, and also drivers allow less of a safety margin near a helmeted rider.

Helmets are still likely a net positive overall, but there is enough reason to at least consider the second-order effects.

[dwaite]

Wearing a helmet is a choice (possibly one with legal consequences, but a choice), which gives a bias in any study which might have shown a behavioral difference by the rider.

[frereubu]

Do you have a source for this? I see this said regularly, but have not seen a link to the study itself.