Police officers sworn to uphold our traffic laws are among the worst speeders on South Florida roads. A three-month Sun Sentinel investigation found almost 800 cops from a dozen agencies driving 90 to 130 mph on our highways. Many weren't even on duty. The extent of the problem uncovered by the newspaper shocked South Florida's police brass. All the agencies started internal investigations. Excessive speed," Margate Police Chief Jerry Blough warned his officers, is a "blatant violation of public trust." The evidence came from police SunPass toll records. The Sun Sentinel obtained a year's worth, hit the highways with a GPS device and figured out how fast the cops were driving based on the distance and time it took to go from one toll plaza to the next. Speeding cops can kill. Since 2004, Florida officers exceeding the speed limit have caused at least 320 crashes and 19 deaths. Only one officer went to jail - for 60 days. A cop with a history of on-the-job wrecks smashed into South Florida college student Erskin Bell Jr. as he waited at a red light in Central Florida three years ago, hitting him at 104 mph. Bell is now severely brain-damaged. "Every day, you pray for a miracle,'' said his father, Erskin Bell Sr. "Had this officer's behavior been dealt with, maybe he would not have run into our son." Law enforcement officers have been notoriously reluctant to stop their own for speeding, and the criminal justice system has proven no tougher at punishing lead-foot cops, records show.