Congestion based tolls were first introduced on I-35W after people initially rejected the idea as unfair (people with more money would save time in rush hour). Then MN decided to do it on a trial basis, on the section from downtown Minneapolis going south to the MSP and MOA and vv). when we tried it, people liked it very much. It's since spread to a couple other sections (more of I-35W and parts of I-35E plus there's a two lane reversible MN-Pass roadway for I-394 going west from downtown Minneapolis). I got a transponder early on (and I've had a couple different versions of the technology) with the idea that even if it only prevented me from missing one flight, it would be well worth the initial fee.

Our usage fees certainly do depend on congestion at the time. Prices range from twenty-five cents to eight dollars. I almost always take the express lane, although I think the most I ever paid was $5.25. When it's super cheap, the express lane might not be faster, but people seem to drive more carefully there so it feels safer to me. I almost never drive in rush hour. The toll also depends on distance very roughly, with for example I-35W costing more if you continue in the express lane south of MOA/I-494 (the circular road that avoids both downtowns) and I-394 costing more if you continue in the express lanes after the special roadway ends at the first north-south highway (MN 100 if you're looking at a roadmap) outside of Minneapolis, roughly where city residential areas end and the first suburb (St Louis Park in this case) begins.

If you want to look at MN traffic and road (blizzard) conditions, google MN 511. I think the website is mn511.org (you don't want the obscure flight number that pops up) and there's also an app that I can use to check traffic conditions in neighboring states. Right now on my phone I don't see any orange or red lines on I-35 or nearby major highways until I get down to the Dallas area and then again north of Austin. In fact, I can scroll down to Mexico, but not much of Canada is covered. Kentucky, Syracuse, and north of Boston look bad today, as expected (winter snowstorms).

BTW, the idea and research behind congestion-based tolls was done by Herb Mohring (RIP), economics professor at University of Minnesota for many years. I guess it's not surprising the the initial demonstration was (finally) done here, probably in the mid-late 1990s.