Using the hanging tables drawn to assure a dead but non-decapitation hanging, I calculated (Fi) that death by collision can occur at about 7 mph with no helmet, and about 5 with a helmet. The mass of the helmet is a factor. For 50 years or so no helmet, then whatever minimal crap I have to wear. Recently with the beanie off, I did, well, headed for a ton on a back road, and as I backed off a sheriff came the other way. He waved. Call me criminal. I've totaled an Oldsmobile with a BSA, banged through garage doors, slid down the highway, outrun cops, with no beanie. However after they forced 'em (Bell lobbied the finks) I did have a couple of serious injuries...all better now. Brand? Brand X, of course! Cops are not certified engineers...a dixie cup? Nobody'd buy that. Kid tells me that down south Santa Barbara (Patron Saint of Gunners!) way, I'd get a ticket... I did have one youthful cl77 experience though...mom insisted that I buy a beanie...and a hornet flew in... Ouch! Many times! In heavy traffic. That decided me that beanie = bs, lonlongtimeago. But yeah, it's situational...I don't cotton to fellas with badges n guns stopping me on the road...that's dangerous!