DECATUR -- Drivers who cause a traffic accident while talking on a cell phone will face a fine of up to $500 under a law that took effect Tuesday in DeKalb County.

The law, believed to be the first of its kind in Georgia, sanctions drivers whose improper usage of a mobile phone was a "contributing factor" in a collision causing death, injury or damage.

County officials said the law applies in unincorporated DeKalb, not its cities. About 80 percent of the county is unincorporated.

The Board of Commissioners had been considering a $100 fine proposed by county Chief Executive Officer Vernon Jones, but they upped the ante when they approved the higher maximum fine Tuesday.

Jones said he proposed the legislation after driving past a wreck several months ago in which cell phone use reportedly played a role. He said he also talked to a county traffic court judge who told him cell phones were a factor in as many as 700 collisions in a year.

"It's becoming more and more of a problem," Jones said. He said the law does not target drivers who use headsets or handsfree devices.