A Burbank jury on Thursday held Los Angeles County liable for almost $770,000, blaming one of its road crews for causing a head-on collision between two motorcycles that left an elderly man with spinal fractures.

Sean Herendeen, 28, lost control of his motorcycle just before 10 a.m. Oct. 30, 2011 after encountering loose gravel left behind by a county Department of Public Works road crew on Little Tujunga Road.

The debris was from shoulder construction project completed 10 days earlier, near the main entrance to the Wildlife Waystation.

Herendeen’s motorcycle slid out from underneath him, crossed the double yellow line into the other side of the road, and hit another motorcycle, ridden by Michael Radner, then 71.

“He suffered fractures in his thoracic spine at three levels,” Radner’s attorney Daniel Sheldon said. “Doctors said he was half-an-inch away from being paralyzed, but he did suffer a severe back injury that’s still bothering him to this day.”

The month-long trial, overseen by Judge William Stewart, concluded with a jury finding the county “100 percent responsible for causing the wreck,” Sheldon said.

The jury awarded $123,000 to Radner for past and future medical expenses, and $640,000 for past and future pain and suffering.

“We think the verdict was fair in comparison to the extreme harm that was caused to Mr. Radner,” Sheldon said. “The injury affects more or less every aspect of his daily living — he’s in constant pain.”

Radner also sued Herendeen, but the jury exonerated him after he showed photos of the accident site, Sheldon said.

“The jury looked at the photos taken by Mr. Herendeen and concluded that it depicted a significant amount of loose gravel on the roadway surface, and that the county road crew negligently created that condition.”

The county had contracted a private law firm to litigate the case on its behalf. Tom Gutteres and Desiri Schultz of Collins, Collins, Muir & Stewart represented the county, but could not immediately be reached for comment.