It amazes me sometimes how, out of the blue, I'll have a drive where the FE is excellent compared with my usual "pretty good". Today I had a phenomenal one, far surpassing anything I've ever experienced before. 210 km (130 miles) of rural and hiway driving after filling up yielded a computer display tank ave of 5.1L/100km (46mpg) with 2 adults, 2 kids, and a trunk stuffed full of golf clubs and luggage.

I've done this drive many times before and usually I get my "typical" highway numbers (around 6.2 or 38mpg if I'm lucky). In fact, I usually get better numbers on the "leaving home" trip, and this one was actually a "coming back home" trip which usually isn't as good. I guess it was a perfect combination of weather conditions and a busy but steady highway which kept the speeds down below the speed limit. The trip started with 30km of rural driving and I was dumbfounded to see the tank ave drop to 4.8L/100km. Something I had never seen before except a minute or two after leaving a gass station in EV. Once I got on the highway it started to climb and I figure back to normal, but as it hit 5.3 I ran into heavy traffic which slowed me down for most of the remaining trip, but also slowly brought the tank ave to 5.1. Took me 15 months to see this...

Two climate control systems, one inside and the other at the tailpipe.

Distance: 29169km (75% city - 20 min trips)
FE: 6.77L/100km or 34.7 mpg
Operating Cost: $0.066/km / $0.107/mile

If this was only a "one-way" portion of trip it was probably two things:

Your lower speeds. Slower speeds really help. (as in 60. 70 is too high)
A tail wind.

And perhaps a little bit of drafting if traffic was that heavy.


My best "longer" trips were:

Madison WI - Chicago (NW suburbs - Arlington Heights). Returning home from HybridFest 2006. 125 miles. 48 MPG.

Detroit (New Hudson NW suburb) - Chicago (Arlington Heights). Last weekend. 300 miles. 47 MPG.

Normally 43 MPG is pretty easy (at around 60-65 miles per hour). On any length of highway trip.

If traffic was steady but slow, like ~40 miles per hour (in my experience, and sorry too early to convert ), I think you can get some pretty impressive mileage as you slip in and out of EV mode, coast, etc. That'd be my suggestion for the primary reason. Though when it's warmed up already before you start tracking (ie, fill up after it's warm) you do lose the initial warmup gas burn which I figure is a major part of why mileage is lower usually--the rest of the trip is compensating for all of that gas lost while getting the engine warmed up.