Back to the original post ... sorry, I can't enlighten you (I think the others have done a pretty good job) but I can commiserate. I've experienced the same thing in the same kind of traffic. Yesterday it poured in Houston as I was driving to work, and I had bumper-to-bumper-stop-and-go-freeway-crawling traffic for 18 miles (took well over an hour). I think the ECO drive monitor indicated I got about 30 mpg for that trip. I think I actually "made up" some mpg once I hit downtown since Houston actually has its traffic lights synchronized, so I can do a lot of battery-powered driving, coasting, and mild braking without actually having to stop.

That said, I find comfort in knowing that if my TCH got "only" 30 mpg, then my previous car would've probably gotten 20 mpg.

I've got about 350 miles on my TCH so I haven't had to fill it up yet. I'll be interested to see what that MPG turns out to be vs. the computer tank average.