DENVER (KDVR) — Two Denver police vehicles were hit by separate drivers during a traffic stop last week, according to a social media post from the Denver Police Department.

On May 7, officers responded to a crash on northbound Interstate 25 near the exit for Alameda Avenue.

The officers were parked with their emergency lights on to direct the traffic away from the scene of the crash. Despite the lights being on, two separate vehicles crashed into the officers’ vehicles.

One driver caused minor damage to a Denver police vehicle and was cited for careless driving. The second driver caused extensive damage to a police vehicle and was cited for careless driving, as well as arrested for allegedly driving under the influence during the crash.

Officers were in their vehicles during the incident, with one uninjured and the other taken to the hospital with minor injuries.

“Traffic safety is a shared responsibility! If you come upon flashing lights, emergency vehicles, tow trucks, or disabled vehicles while driving, move over at least one lane or slow down if it’s not safe to move over. And don’t drive under the influence,” said the department in the post.

Denver’s outdoor warning sirens will sound for three minutes on Wednesday morning as officials test the city’s emergency systems.

All 86 outdoor sirens are scheduled to go off at 11 a.m., and at the same time the wireless emergency alert system will send a test text message to all mobile phones in Denver.

People in neighboring counties may also receive the emergency alert message, the Denver Office of Emergency Management said in a statement.

“Speed and clarity are critical in an emergency,” Executive Director Matthew Mueller said in a statement. “This test helps ensure Denver can deliver alerts across multiple platforms, so people know what to do right away.”