At 25km an hour a helmet would fail, you'd would instead have an extended impact duration. Any decrease in the collision forces must necessarily be accompanied with a increase in impact duration. Plus the 30% increase in radius around the head would have exposed you to rotational forces that could have done serious damage. It's very lucky that you weren't wearing a helmet.
At 25km an hour a helmet would fail, you'd would instead have an extended impact duration. Any decrease in the collision forces must necessarily be accompanied with a increase in impact duration. Plus the 30% increase in radius around the head would have exposed you to rotational forces that could have done serious damage. It's very lucky that you weren't wearing a helmet.