The Derry to Belfast road was closed by police for several hours on Monday night following sectarian clashes between rival crowds at the Glenshane Pass.
Three men and one police officer were injured, a civilian car and a police car as well as a minibus were damaged.
Two men arrested at the scene on suspicion of causing criminal damage and assault were later released on police bail, pending a report to the Public Prosecution Service.
Local people claim the trouble started when the minibus carrying supporters of a junior football team returning to the Waterside area of Derry stopped along the roadside to enable the supporters to urinate.
It halted beside a hunger-strike commemoration billboard, which was damaged shortly after the minibus pulled on to the roadside. Local people then arrived on the scene and the clashes ensued.
Brothers Rory and Kieran Hegarty sustained injuries and another local man, John Convery, alleged he too had been assaulted and his car damaged.
PSNI Chief Insp Paul Douglas said up to 50 people were involved in the sectarian clashes. "Three men were assaulted at the scene and a car was damaged. There was also substantial damage caused to the minibus which had most of its windows smashed with stones. A police officer was struck on the head by a missile and a police car was also damaged.
"Two people were arrested on suspicion of assault and causing criminal damage following the public disturbances. The incident occurred when the occupants of a minibus returning from a football match and upwards of 30 other people clashed near a hunger-strike billboard, which had been wrecked.
"Three men were assaulted at the scene and unfortunately there was substantial damage to the minibus. Because the matter is now the subject of a full police investigation I really cannot elaborate on the details of the incident, but people need to show respect for the traditions and cultures of others. We need to find better ways of resolving our differences without resorting to this type of violence."