A highway accident that left two men dead may have been caused by negligent maintenance of a tractor-trailer, prosecutors contended Wednesday in a Florida trial. Robert Lee Jackson Jr. is charged with two counts of manslaughter by culpable negligence for the June 2002 collision that killed a firefighter and an obstetrician, according to a May 5 report in the Orlando Sentinel. Traffic investigators testified they found a number of critical problems upon inspecting the vehicle after it plowed into a media on Florida’s Turnpike. The problems cited were: one bald tire on the trailer; inadequate brake lining for safe stopping at five locations on the tractor and trailer; inoperative/defective brakes at one location each on the tractor and trailer; brakes out of adjustment at one place on the tractor; and no required brakes at two places on the tractor and one on the trailer. Windshield wipers were also inoperable, according to the Sentinel report.The investigator said oil and grease were found in the reservoir tank of the air-brake system and that the last motor-vehicle inspection certificate displayed on the tractor was from April 2000. The inspection sticker on the trailer was unreadable, he said. Both should have been inspected annually.Jackson, 38, told investigators that traffic in front of him unexpectedly slowed down, apparently because of an accident in the median. The two men were helping the occupants of an overturned pickup truck. Jackson said he swerved into the median to avoid hitting a vehicle in front of him, not realizing people had gathered on the grass. He hit the pickup, causing it to spin, then hit a guardrail, Kelly's car and another tractor-trailer, investigative reports show.Jurors will have to decide whether the crash and the resulting deaths and injuries were an unavoidable tragic accident, as Jackson's lawyer contends, or whether he caused the crash by not properly maintaining the rig. Jackson faces a maximum of 36 years in prison if convicted.