I-270 Variable Speeds Become Advisory

Changes begin Friday that would make the variable speed limit signs on Interstate 270 advisory only in St. Louis.

The signs were put in place three years ago, but their impact on traffic congestion was minimal, a Missouri Department of Transportation (MoDOT) traffic study determined. The study, conducted by the Missouri University of Science and Technology with consulting firm HDR, Inc. and Heartland Market Research, concluded that with further refinement of the system and increased driver compliance, the benefits could be much higher.

The signs did cut down on accidents along the interstate, though, making it the safest highway in the St. Louis metropolitan area, said Tom Blair, MoDOT assistant district engineer.

Advisory speed limits will not be enforced, but are instead meant for safety. They will display speeds from the 60-mph limit, to 10 mph, depending on the amount of traffic, said Blair.

"The advisory speed limit is similar to having advisory speed limit signs posted on curves and ramps. It is the suggested speed to safely travel that stretch of road," said Blair.

Two portions of the interstate won't have the same speed limit as the rest of the highway. Southbound I-270, between Dorsett Road and Page Avenue, along with northbound I-270, between Gravois Avenue and Interstate 44, will have a 45-mph speed limit. Both of those areas are in around-the-clock work zones.