No other source, but keep in mind that helmets are tuned for a certain force level. Too durable and helmet does not reduce peak force as it does not crush. Too weak and it crushes quickly, again with little reduction in peak force. This should just empasize to use the 25% number here though since the forces are more representative.
Redacting “won’t do much of anything” except as implied by 25%, but keep in mind that if peak accelerations are much higher than the given case, the helmet will be less effective due to the above. This may or may not be the case in car crashes depending on speed.
No other source, but keep in mind that helmets are tuned for a certain force level. Too durable and helmet does not reduce peak force as it does not crush. Too weak and it crushes quickly, again with little reduction in peak force. This should just empasize to use the 25% number here though since the forces are more representative.
Redacting “won’t do much of anything” except as implied by 25%, but keep in mind that if peak accelerations are much higher than the given case, the helmet will be less effective due to the above. This may or may not be the case in car crashes depending on speed.