DENVER (KDVR) — Boulder police are investigating after four signs with explicit messages were found affixed to speed limit signs around the city on Tuesday.

The signs were found at:

Table Mesa Drive and South Broadway

28th Street and Jay Road

28th Street and Palo Parkway

28th Street and Diagonal Highway

28th Street, also known as North Foothills Highway, is also Highway 36, representing where the highway becomes a local road through Boulder. It is a major thoroughfare for motorists, as is Diagonal Highway.

The signs used explicit language telling drivers to “slow down [expletive],” “put down the phone [expletive],” and “don’t kill any kids today.” The fourth sign listed the speed limit as “slow the [expletive] down.”

According to the city of Boulder’s crash data interactive map tool, there were three fatal crashes in Boulder during 2023, but none occurred near where the signs were placed. However, a woman was killed on Broadway near Raleigh Road on Sept. 27 after she was struck by a car just before 5 a.m.

Another 55 crashes resulted in incapacitating injury. Five of those crashes appeared to be on 28th Street in Boulder. The city has been focused on reducing crashes on roadways through its 2023-2027 Vision Zero Action Plan and has implemented a citywide, default speed limit of 20 mph.

The Boulder Police Department told FOX31 that as of Tuesday evening, the city’s Transportation and Mobility Department was in the process of removing the four signs identified.

It’s unclear if there are any more signs, or who was placing the signs around the city. Boulder police are investigating the signs for criminal tampering, and are asking that anyone with information call Boulder police dispatch’s non-emergency line at 303-441-3333 and reference case 24-12182.