The speed limits on Interstate 270 during the morning rush changed a whopping 40 times between May 27 and May 30, according to the Missouri Department of Transportation. In the evening rush, they changed 51 times.

The four days mark the first week of variable speed limits on I-270 (since May 26 was Memorial Day, it wasn’t included). For those of you who haven’t seen them, electronic speed limit signs show different speeds on I-270 depending on congestion levels. And so the question arises. Are drivers paying any attention to these? One morning last week, I was on northbound I-270 when speeds were 40 mph. It seemed like traffic was going at least 10 mph faster.

The department’s review of drivers’ reaction was positive.

On May 28, a crash involving a tractor-trailer caused corn syrup to spill all over the interstate. Speed limits on southbound I-270 near McDonnell Boulevard dropped. According to MoDOT traffic engineers, most traffic seemed to obey the dropping limits, which meant shorter than usual backup for a total interstate closure.

“MoDOT traffic experts are still working hard to get experience to manage traffic by using variable speed limits,” said Tom Blair, St. Louis assistant district engineer. “We appreciate the efforts of people who have been obeying the variable speed limits and encourage those drivers who may be a little skeptical to give variable speed limits a chance.”