The new policy was implemented by ExxonMobil in conjunction with the company's recognition of National Safety Month in June. The policy was developed after ExxonMobil commissioned an analysis of available science on cell phone use that concluded talking on a cell phone significantly degrades driving performance.

The National Safety Council, which has declared this month to be "Crash-Free June," praised Exxon Mobil for its safety leadership in enacting a ban on cell phone use.

"ExxonMobil has again demonstrated its safety leadership by recognizing a significant driving hazard and acting to reduce this hazard for their thousands of employees and contractors who operate motor vehicles and travel on company business," said Alan C. McMillan, president of the National Safety Council.

ExxonMobil recently reviewed nine studies "that gave clear evidence that cell phone use while driving leads to a sharply increased accident risk," said the company in a statement. "Drivers using cell phones were found to have braking reaction time three times longer than drivers under the influence of alcohol, and a four-fold increase in risk compared to not using a cell phone."

According to McMillan, "The council's policy recommends that employers assess whether to allow employees to use cell phones and other devices while driving, and if so, what sensible restrictions should be followed. ExxonMobil has demonstrated that the safety and health of its employees and contractors is a key corporate value and we applaud them for that."