Several states, including California and New York, have introduced laws against talking on a cell phone while driving, but they still allow the use of hands-free devices, such as Bluetooth headsets. However, studies have shown that hands-free devices may not help. It appears that it is the distraction of dialing or talking that is dangerous, rather than the act of taking a hand off the wheel.

A study by the National Highway Traffic Safety Administration in 2006 found that dialing or talking on the phone was the cause in 7 percent of crashes and near-crashes. For the study, drivers had onboard “black boxes” that recorded their actions.

Last year, 41,059 people died in traffic accidents.

Aegis Mobility, a Canadian software company, announced this month that it has developed software called DriveAssist that will detect whether a cell phone is moving at car speeds. When that happens, the software will alert the cellular network, telling it to hold calls and text messages until he drive is over.

The software doesn’t completely block incoming calls. Callers will hear a message saying the person they’re calling appears to be driving. They can hit a button to leave an emergency voice mail, which is put through immediately.

Aegis’ software will work on phones with Windows Mobile software or Symbian software (used in phones from Nokia and Ericsson). It uses the phone’s global positioning system chip to detect motion, aided by the cell-tower signal. To work, the software has to be supported by the cellular carrier and can be managed remotely through a web site.

Nationwide Mutual Insurance Co. said it plans to offer a discount of up to 3 to 10 percent on family policies for people who use DriveAssist.