Just zis Guy, you know? wrote:

Silly boy. There were no helmet studies in 1940 because nobody was
gullible enough back then to believe that cycling was some kind of
extreme sport!

Guy

Wasn't there a folding bike used by the parachute regiment? I'm sure
riding a bike around Normandy on D-Day 1944 would qualify as an extreme
sport, regardless of how good your troopers helmet was.
Kids today have got it easy.