I've often wondered how many lives would be saved if people wore helmets during daily driving. I'd bet a lot. Of course, good luck getting people to do it.
I would not be surprised if helmet usage increased serious accidents/injuries and fatalities. The peripheral vision (for crossing roads, rotaries, and spotting pedestrians) is vastly worse wearing a helmet, at least the SA full-face helmets I've worn in amateur motorsports.
Race tracks don't have most of those hazards, and control most of the pedestrian hazards, with the limited pedestrians on the hot side of the pit wall assuming much of the responsibility for their own safety.
This would be offset by a reduction in head injuries (with a possible increase in neck and spinal injuries). I think I'd bet a full study would show an overall decrease in safety.
"vastly worse wearing a helmet, at least the SA full-face helmets"
Which is why the research into this topic focuses more on headbands, which mostly protect the forehead, than the entire head. See http://www.copenhagenize.com/2009/10/australian-helmet-scien... for a summary of Australian research and a sketch of the head gear. They quote:
> But more impressive were the estimates of introducing protective headwear for car occupants. The authors of the report estimated that the annual reduction in harm would be in the order of $380 million. The benefit of padding the head is that the head is protected from strikes with unpadded automotive components, exterior objects and in vehicles that predate any eventual introduction of padded interiors."
I actually wonder if there is a limit on the size of the A pillar in cars. The car I drive right now seems like it has a larger A pillar than the (super old) car I had before, presumably for safety. But it's almost caused me to get into several accidents as I am almost completely blind when slighting left. Just the other day I nearly hit a pedestrian who was crossing against the light. I slowed down for the turn but had the green light, and the pedestrian was crossing the street at just the right speed to stay in the blind spot of my driver's side A pillar. If I hadn't moved my head to double check, I would have run them over. I've never had this issue on any other car, but it's a big problem for me right now.
So imagine that blocking a good section of your forward vision, and a helmet blocking anything to the sides... motorcycles have very small blind spots as the rider can swivel anywhere with no cage blocking them. Helmets are a minor contributor. But cars don't have that luxury.
