Tim, who seems to always be where the traffic action is, discovers what happens when somebody's car overheats in one of the I-93 tunnels:
... He put his windows down because he had to turn on the heat to cool down the engine, which has always been a weird paradox. It wasn't enough, though, because his car started spewing steam. He had to pull over by cutting through two lanes of traffic, and where he stopped meant anyone trying to use the Government Center/North End ramp would have to snake around him. I doubt this helped traffic.