Freakonomics looks at the effect of helmet laws on motorcycle deaths.
Another disturbing trend is the decrease in states with universal helmet laws. Helmet laws are the only motorcycle safety strategy whose effectiveness is rated as five-star in NHTSA’s highly-regarded publication, “Countermeasures That Work.” Only 19 states currently require all riders to wear helmets, down from 26 in 1997. Earlier this year, Michigan repealed its universal helmet law, while similar legislation has been introduced in five other states. No state has enacted a universal helmet law since Louisiana reinstated its requirement in 2004.