Ever driven at night and noticed the small reflectors in the roadway that show where the lanes lines are? They’re easy to miss during the day. They’re called raised pavement markers or RPMs. Both Missouri and Illinois have used them extensively on interstates and state highways. You only see the reflector on top of the device when you drive, but it’s attached to a 7 pound piece of cast iron that’s embedded in the roadway. The problem with these safety devices is they can come lose. When the do, a passing truck can fling them in the air like a metal missile and they can do a lot of damage when striking a car at 60-70 miles an hour. A long time truck driver with the Illinois Department of Transportation told me that snowplows frequently damage RPMs and even knock them loose.

A Missouri Department of Transportation internal memo shows that MODOT failed to set up a system of routine checks on RPMs to find and fix the loose ones. After paying out nearly $340,000 in damage claims, Missouri is phasing out the safety devices and checking them once every year, instead of the once-every-three year schedule it followed when first installing them. On the other hand, IDOT doesn’t see what all the fuss is about. Illinois says the benefits outweigh any dangers and regularly checks them, but only once every four years. Less frequently than MODOT when the agency’s own lawyer wrote the memo saying the state wasn’t checking them as regularly as the manufacturer recommended. No wonder a short drive along I-64 in St. Clair County turned up numerous damaged RPMs or places where they were missing. Other states like Wisconsin, Michigan and Minnesota are also phasing out RPMs. MODOT is replacing RPMs with a highly reflective lane stripe. IDOT plans to keep using them. Driver beware!

On the Illinois side of the metro you’ll find raised pavement markers on all the interstates in the metro east. In Missouri, you’ll find them on a stretch of I-44 and I-55 south of downtown. There are RPMs embedded in I-44 in Fenton, near the Chrysler plants. You’ll also find them on Highway 141 and on I-70, from north of downtown, westward to the Fulton, MO exit.