Interstate 270 drivers: watch those speed limit signs. Today the Missouri Department of Transportation started changing the speeds on I-270’s electronic speed limit signs based on traffic conditions. Here’s the run down.

The first change happened around 6:30 a.m., when increasing congestion on northbound I-270 resulted in a speed limit drop to 55 mph between Highway 21 and Interstate 44. Ten minutes later, the speed limit dropped to 50 mph. It dropped to 45 mph at 7:30 a.m., and then 40 mph at 7:48 a.m. When congestion eased, at 8:50 a.m., the speed limit increased to 55 mph, and to 60 mph by 9 a.m.

That was just northbound I-270. The speeds also changed at different times on the southbound side between Dorsett Road and Olive Boulevard.