And as for expense vs safety for modern helmets: think about who the manufacturers are marketing the expensive helmets to - racers and wannabe racers. Racers pay big bucks to be fast. That means the best possible balance between weight, aero and comfort/heat dissipation. Notice that safety does not show up. CPSC standards must be met for a US sold helmet. So manufacturers are burdened with making the CPSC limits while finding that optimum blend of the important stuff. Improving safety would come at the cost of at least on of the elements of weight, aero and comfort/heats dissipation. Those high end helmets are going to toe closer to the CPSC minimum than the Walmart job because real engineering time is spent to get there.

Bottom line - if you want safety, stay away from big dollar helmets. (Except that the MIPS technology may radically lower your injuries under the right conditions.) I paid real money for the POC Trabec. Better safety at the cost of aero and weight. (Surprisingly comfortable, even in hot weather.)

Ben