Arkansas, Texas, Kentucky, Louisiana, and Florida weakened laws governing universal helmet use and limited coverage to those less than 21 years old.
The increase caught industry and government officials off guard because the number of accidents fell in the 1990's even as sales were climbing, and all but four states had helmet laws and other regulations governing motorcycle safety.
Seattle, which is considering a bike-share program, has required helmets for all riders since a law governing the unincorporated county and suburban cities was extended in 2003.
Ferrell, who is also the chairman of the medical committee of the International Equestrian Federation, the sport's governing body, said he planned to convene a meeting to discuss helmet use.
But in football, use of the helmet is a burning issue – this week the NCAA, college football's governing authority, agreed a $70m settlement over a concussion-related lawsuit; the NFL's deal with former players could cost it $875m.
And he delighted in Germany's victory in the World Cup even if football's governing body Fifa refused to let him use a picture of the trophy on his new helmet.
The national governing bodies of high school and youth football, covering about 4.4 million players ages 6 to 18, require only that helmets emerge from the factory passing the standard set by the National Operating Committee on Standards for Athletic Equipment (Nocsae).
NOTES The jury for the governing body of international bobsled and skeleton, known as F.I.B.T., denied a protest placed by the United States skeleton team concerning the helmet of Amy Williams of Britain.
Select governing board members.
