WASHINGTON (Reuters) - Driving distractions, primarily by cell phones and other electronic devices, are associated with up to 25 percent of U.S. car crashes, according to a report released on Thursday.
The study by the Governors Highway Safety Association (GHSA), a nonprofit group that works to improve traffic safety, assessed research from more than 350 scientific papers published since 2000.
It showed that drivers are distracted up to half the time and that crashes caused by distractions range from minor damage to fatal injury. Cell phone use raises the risk of crashing, but texting is likely to increase crash risk more than cell phone use.
"Despite all that has been written about driver distraction, there is still a lot that we do not know," GHSA executive director Barbara Harsha said in a statement.
"Clearly, more studies need to be done addressing both the scope of the problem and how to effectively address it."
Data from the National Highway Traffic Safety Administration (NHTSA) shows that in 2009 alone, nearly 5,500 fatalities and about half a million injuries resulted from crashes involving a distracted driver.
Deaths due to distracted driving presented 16 percent of traffic fatalities in 2009, a rise from 10 percent in 2005.
"When it comes to distracted driving, one thing is clear: any activities that take extended focus away from the primary task of driving are both unsafe and unwise," Lynda Tran, spokeswoman for the NHTSA, said in a statement.
The GHSA suggested measures for states and organizations to reduce distracted driving.
The report said laws banning hand-held cell phones while driving reduced their use by roughly half since they were first implemented, but cell phone use increased subsequently.
There is no conclusive evidence on whether hands-free cell phone use is less risky than hand-held use, the report said. Evidence is also lacking on whether cell phone or texting bans have reduced crashes or injuries.
The GHSA suggested a complete ban on cell phone use, hands-free or not, for novice drivers, who are the highest-risk. It also recommended a texting ban for all drivers.
Thirty states and the District of Columbia have prohibited the use of all cell phones by novice drivers and 41 states and Washington, D.C. had prohibited texting by novice drivers. Thirty four states and the District of Columbia have enacted texting bans for all drivers. But the report said texting bans have proven difficult to enforce.
Because the research and data on these laws' effectiveness is not definitive, the report recommends the 41 states without handheld cell phone bans hold off and monitor existing laws before enacting their own.
The GHSA represents the state and territorial highway safety offices. Its members are appointed by their governors.
Reporting by Molly O'Toole; Editing by Jerry Norton and Patricia Reaney