An airborne tire tread appears to have triggered a fatal accident involving a motorcyclist and tractor-trailer this week, according to Gwinnett County authorities.

Police say Lonnie Cross, 35, was riding his motorcycle Wednesday around 5:30 p.m. in the left lane of northbound I-85 at the I-985 split when he hit the tire tread after it had been struck by another vehicle.

Cross lost control of his motorcycle, and after laying the motorcycle down on the roadway, he ended up resting in the center lane in the path of an oncoming tractor-trailer, police say. The driver of the truck could not avoid running over Cross, police say.

Cross died at Gwinnett Medical Center. Police say no charges were pending.

For some time, all lanes of I-85 were closed in the area, with traffic being re-routed to I-985.

In recent months at least a half dozen motorcyclists have been involved in fatal crashes on metro Atlanta highways.

Police say Emanuel R. Mitchell, a 31-year-old Norcross resident who was riding a black 1990 Kawasaki Vulcan motorcycle, died Aug. 20 after being struck by two vehicles on I-75 near Windy Hill Road in Cobb County.

Police say the accident was caused by Brandon Michael Weston, 32, of Smyrna, who was driving a silver Porsche 944 and fled the scene with passenger Pamela Kay Rice, 41, of Marietta.

Police say after the fatal hit and run, Weston and Rice conspired to have the car taken to a repair shop in Alabaster, Ala. They were arrested nearly two weeks after the accident and face charges of second-degree vehicular homicide, hit and run, tampering with evidence and several other charges.

In another case, a 74-year-old woman riding on the back of a Harley Davidson on I-285 in south Fulton County was killed when the motorcycle ran into an SUV that had stopped with a flat tire.

Motorcyclists also have been the victims of motorists driving under the influence.

Darrin Murphy, 42, is accused of ramming a motorcycle in late May and killing recent Georgia Tech graduate Liam Rattray near the Vortex restaurant was arrested previously for DUI, authorities say.