IMO David has pretty much "nailed it" in regard to a long highway trip under favorable conditions

Many threads in this forum are loaded with tips on driving techniques that will improve on this somewhat.

But, as the window sticker says. "Your mileage WILL vary." In my experience the variation is a whole lot more in city driving and commuting than on highway trips. Based on the computer, I have seen city trip mileages vary from under 10 mpg to over 60 mpg in the TCH. Accordingly, I could average anywhere in between those limits that I wanted to --- as long as I could choose my trips. Of course, I usually can not choose my trips, and my usual trips are on the unfavorable end of the scale; so I tend to average about 30 mpg.

Some drivers are fortunate enough to have the kind of daily commute that maximizes the TCH economy. I am not. some who have reported to this forum have mentioned that they have actually re-arranged their commute to take advantage of more favorable trip. Who knows, you or I may be able to do this.

We should all be willing to make some lifestyle changes for the sake of conservation.

Recently, I needed to make a couple of trips to the local IRS office and to the airport. I averaged 45 mpg on the airport trips and over 50 mpg on the IRS trips. I suppose that it could come to pass that I would wind up with a job at the airport and get my average up close to 45, but I sure wouldn't want to need to visit the IRS every couple of days in order to get my average up closer to 50.