Police caught 27 drivers under the influence of alcohol after the Zwarte Cross festival on Monday, Omroep Gelderland reported. Police checked 1,428 people as they left the event.

Alcohol was the only substance detected in 25 cases. Two drivers tested positive for alcohol and also produced positive saliva tests. The results could indicate drug use, but blood tests are required to confirm that. Police seized one driver’s license because the drunk person was a novice driver.

The operation is a familiar part of the Zwarte Cross departure day. Regular festivalgoers have known for years that police conduct a large-scale alcohol check on the Monday when attendees leave after several days of festivities.

The departure also caused traffic congestion on several roads around Lichtenvoorde. At about 11 a.m., traffic on the N18 from Lichtenvoorde toward the connection with the A18 motorway stretched for about 9 kilometers. On the opposite side of the village, toward Aalten, the N313 had a traffic jam of about 3 kilometers.

For drivers stuck in the congestion, dialect rock band Heinoos provided an unusual distraction. The band members stood singing along the roadside in the grass verge, equipped with guitars and several large speakers. They tried making the traffic jam more bearable, the band said.

Two stunt performers were injured during separate catapult stunts at the Zwarte Cross festival. Laurent Arrabito broke his ankle upon landing Saturday. A day earlier, Jim van Nes suffered a severe concussion when his knee struck his head on landing. He was unconscious for about two minutes, was taken to a hospital, and was released the following morning.