WASHINGTON - Motorcycle riders' deaths in the US have increased over the the past 10 years to 4500 in 2011, the same total as 2010, a study has found.Motorcycle deaths doubled from 2116 in 1997 to 4232 in 2008 and in 2010 rose slightly to 4502. During the same period passenger vehicle deaths decreased by five percent, according to the Detroit News.Governors Highway Safety Association chairman Troy Costales said: "It's disappointing that we are not making progress in motorcycle safety, particularly as fatalities involving other road users continue to decline. 'STEP BACKWARDS'"As the study notes, the strengthening economy, high fuel prices and the lack of all-rider helmet laws leave me concerned about the final numbers for 2011 and 2012. Every motorcyclist deserves to arrive at his or her destination safely."The GHSA said a review of the first nine months of 2011 found motorcycle deaths fell 1.7%. Prior surveys have found that motorcycle deaths rise in the last three months of the year, so 2012 was likely to end without a decrease..In April 201, Govenor Rick Snyder signed legislation to let riders over 21 ride with a helmet if the chose to and had addition insurance cover.Barbara Harsha, executive director of GHSA, said: "The repeal of the universal helmet law was a giant step backward and has national implications."The GHSA reports that helmets prevented 37% of fatal injuries in a motorcycle crash and 41% of fatal injuries to pillions. DEATHS INCREASEDEarlier in May, National Highway Traffic Safety Administrator David Strickland said he was "very concerned" about ending mandatory helmet laws, the DetNews said.Strickland said: "Every state that has repealed its mandatory helmet law has seen an increase in motorcycle deaths."After helmet laws were repealed, motorcyclist deaths increased by 108% in Louisiana, 81% in Florida, 58% in Kentucky, 31% in Texas and 21% in Arkansas.Costales said: "The good news is that we know how to prevent crashes and the resulting injuries and fatalities involving motorcycle riders' and their passengers. There are effective strategies that, if implemented, can make a difference."