An out-of-state driver was killed Wednesday afternoon when his vehicle crashed on Main Street in South Portland.

The driver, who was alone in the vehicle, was pronounced dead at the scene. His name and age won’t be released until police contact his relatives.

Main Street was shut down for just under two hours, and an officer who was directing traffic was hit by the rearview mirror of a passing vehicle. Police said the officer suffered a minor injury and drove himself to the hospital to be checked.

A news release on the South Portland Police Department’s Facebook page said alcohol may have been a factor in the crash, which happened around 3:50 p.m.

Police said the vehicle was going south in the vicinity of 499 Main St. when it crossed the raised divider and went off the road and down the embankment on the other side before hitting trees.

Police detoured traffic around the stretch of road between Cash Corner and the Thornton Heights neighborhood at the height of the afternoon rush hour, causing significant delays.

Police said the vehicle had out-of-state registration and the driver was licensed in another state.

“We do believe that alcohol may have been a factor, as well as a possible medical emergency,” police said in the release.

Police said several people saw the crash and provided statements. Accident reconstructionists from Scarborough and Windham assisted South Portland police with the investigation.

The investigation has been turned over the state Medical Examiner’s Office.