The National Conference of State Legislatures said about 100 bills are pending in 40 states dealing with cell phone use while driving, according to the San Jose Mercury. Requiring a driver to use a headset is the most common safety proposal. But the article said there is no evidence that using a hands-free device reduces the risk of an accident. There is also no evidence that using cell phones increase the number of traffic accidents. But an average of two people are killed each day in the United States due to accidents caused by cell phone use, said Donald Redelmeier, a professor at the University of Toronto and co-author of a 1997 article analyzing traffic accidents. This is less than 2 percent of the total number of people killed each year in accidents.