No, Hot Lanes are not roads that have caught fire. Hot Lanes or High Occupancy Toll lanes are a lot like HOV (high occupancy vehicle) lanes, which you are probably familiar with. The difference with HOT lanes compared with HOV lanes is that cars with low occupancy, i.e., just the driver, can travel in Hot Lanes too, they just have to pay a toll. There are many models for tolls but one of the cooler ones is MnPASS.
MnPass is an electronic tolling device that works with a transponder that snaps on to your windshield, which means no stops at toll booths. Sensors built into the lane work with MnPass and pricing varies for the Hot Lane. In many cases, MnPass has no physical barriers, so it's a cost effective system. Critics call Hot Lanes Lexus Lanes because it lets drivers pay for faster transport without car pooling.
The Hot Lanes' Wiki page has a list of the roads that use the system. Turing HOV lanes in HOT lanes is silencing many critics that say HOV lanes are under used. HOT lanes are also a good source of revenue for governments. The Hot Lane concept is very new but I can really see it taking off. No one likes tolls, but traffic certainly is not getting any better. Moving some of those cars along quicker might even please people who are concerned about the environment, as the cars spend less time idling or moving slowly down on the road.
[Source: DOT, YouTube]