Mobile phones and driving safety
Several studies have shown a relationship between mobile phones and driving safety.

# Research

## Prevalence
The U.S. National Highway Traffic Safety Administration (NHTSA) reported that in 2005 about 10% of all vehicles on the road at any given daylight hour were using a mobile phone, up from about 8% the previous year..

## Handsets
Research indicates that using a mobile phone while driving is as dangerous as driving while intoxicated and mobile phone use while driving is far more prevalent than drunk-driving. Talking and driving at the same time lowers the driver's reflexes, rendering them slower to react to and avoid other drivers.
One study of almost seven hundred Canadian drivers showed a rate of collision four times higher when using a mobile phone than when a mobile phone was not being used. A study in The New England Journal of Medicine reports that drivers who used mobile phones while driving were four times more likely to crash than those who don't, a rate equal to that for drunken driving at the 0.08 g/dL blood alcohol concentration (BAC) level.
An experiment conducted by the American television show MythBusters concluded that use of mobile phones while driving poses a similar risk as someone operating a vehicle while under the influence of alcohol. 

## Hands-Free
Many studies argue that the increased "cognitive workload" involved in holding a conversation is the real danger, not the use of hands.  Several studies carried out at the Accident Research Unit at the University of Nottingham have warned of the dangers posed by driving whilst talking on a mobile phone. As these studies deal with the effect of increased attentional load on driving performance, they also apply to hands-free phones, which are considered by some countries to be safe. The major problem is that the person with whom the driver is conversing cannot see the traffic situation and therefore does not regulate their level of conversation to allow the driver to concentrate when, say, approaching a junction. This problem does not apply to conversations with a passenger, as passengers can regulate the flow of conversation according to the perceived level of danger, and also provides a second pair of eyes to spot hazards. 
A study carried out by the University of Utah found that driving while using a mobile phone is "at least as dangerous as driving while over the legal alcohol limit". They also found that hands-free devices do not reduce the distraction caused by talking on a mobile phone. According to a study published in the British Medical Journal and funded by the Insurance Institute for Highway Safety, there was only a slight safety benefit from using a hands-free phone. The study showed that drivers who use cell phones, even hands-free models, are four times as likely to be involved in wrecks involving a serious injury than are drivers who do not use cell phones.

# Legislation
Accidents involving a driver being distracted by talking on a mobile phone have begun to be prosecuted as negligence similar to driving while intoxicated. In the United Kingdom, from 27 February 2007, motorists who are caught using a hand-held mobile phone while driving will have three penalty points added to their license in addition to the fine of 60. This increase was introduced to try to stem the increase in drivers ignoring the law. In the Canadian province of Newfoundland and Labrador, it is illegal to use a hand-held mobile phone while driving, but there are currently no laws on this subject in the rest of Canada.
At least 30 countries restrict or prohibit mobile phone use while driving:
- Japan, Portugal and Singapore all prohibit mobile phone use while driving.
- Countries that prohibit the use of hand-held mobile phones while driving are: Albania, Australia (in the state of New South Wales learner and first year provisional licence holders are not allowed to use mobiles even in hands free mode), Belgium, Brazil, Chile, Croatia, Denmark, Egypt, Finland, France, Germany, Greece, Hong Kong, Hungary, Iceland,Ireland, Israel, Italy, Malaysia, the Netherlands, Norway, Poland, the Philippines, Romania, Slovenia, South Africa, South Korea, Spain, Switzerland, Turkey, the United Arab Emirates, and the United Kingdom.
- Legislation to restrict mobile phone use has been proposed in 40 states in the United States.
California, Connecticut, New Jersey, New York, and Washington, DC have passed such a law. The state of Arkansas voted on such a law, which took place in the last week of January 2007. In the United States, such laws were first passed by individual cities and towns, until state legislatures began to pass similar laws. The first American town to pass such a law was Marlboro Township, New Jersey.  California's 2007 law requires the use of hands-free wireless phones as of July 1, 2008.
- California, Connecticut, New Jersey, New York, and Washington, DC have passed such a law. The state of Arkansas voted on such a law, which took place in the last week of January 2007. In the United States, such laws were first passed by individual cities and towns, until state legislatures began to pass similar laws. The first American town to pass such a law was Marlboro Township, New Jersey.  California's 2007 law requires the use of hands-free wireless phones as of July 1, 2008.

## Effectiveness of legislation
Current laws banning cell phone use in New York and Connecticut have proven to be ineffective, due to a lack of visible enforcement.  The percentage of offenders decreased from 2.3% to 1.1% immediately after the ban was implemented, but after being in effect for a year the percentage increased to 2.1%, which is not significantly different from the pre-ban figure. The authors of the study conclude that "vigorous enforcement campaigns accompanied by publicity appear necessary to achieve longer term compliance."