I love the car - it's big enough for my mom-duties (two carseats, stroller, etc) and is my own personal Kyoto Accord (since our President blew it off)...

But what's up with the less than stellar mileage. I expected a bit better than 21.7 mpg... sheesh. My dad has a prius and gave me all the tips - infalted tires, no AC, super slow accelleration, coast whenever possible. But I have seen the gas engine ON when my foot is off the gas and I'm coasting down a hill!

Does it need adjustment or is the mileage hype a bunch of hooey?

 

Well, there may be many reasons the mileage is less than expected:
short trips are killers on mileage. If you do a lot of short hops, you might end up with half the mileage you could average on long trips. Whether the gas engine is ON while coasting, may depend on a number of factors: state of battery, how recently trip started, AC is on, etc...
Bottom line may still be (unless these were all short trips), your mileage of around 21mpg may still be about 50% more than a non-hybrid highlander would have gotten under similar circumstances. Bottom line is also that the HH - as advanced as it is, is still a heavy and tall vehicle. Heavy means lower mileage during city trips, tall means lower mileage on highway, compared to lighter, smaller vehicles such as HCH, Prius or Accord.
One last note: mileage will likely improve somewhat after your engine and more importantly the tires, are fully broken in.
All that aside, congrats on getting a hybrid and implementing your own Kyoto Protocol!

 

After the engine is warmed up (about 5 minutes, or use in the past couple of hours) go out for a highway drive 10 miles to and back. Zero your tank odometer so your trip mpg is obvious. If the trip mpg at 60 mph is less than EPA, further trouble-shooting is in order.

 

Thanks for the tip. Sadly, I don't think my Highlander Hybrid has the "trip mpg" display. The standard model doesn't have the big screen that the limited model has. The limited model dvd screen is similar to the Prius. The standard model (which is what I have) only has instantaneous mpg, outside temp, and the graphic showing the gas engine, battery etc... nestled in under the odometer and speedometer.

Oh well.

 

What is considered a short commute. I drive about 6.5 miles each way to work - All but 1.5 miles is surface streets with lots of lights. (Which is why I thought the hybrid would be a good vehicle - it's supposed to get better mileage for city driving than highway driving). Is that considered a short hop?

 

Welcome to GreenHybrid, Katie. Congrats on being the first Highlander in the database.

It will be interesting to see how your mpg changes after a few thousand miles of driving. I would expect your mpg will increase over time. I don't think the "mileage hype is a bunch of hooey".
Even in the RX 400h I was able to meet EPA estimates.

Have you ever driven your Dad's Prius on your route? If so, how close were you to EPA estimates in that vehicle?

 

Hi Katie,
I would say that 6.5 miles is fairly short, and at least for the first half of that trip you will be driving at about half or two thirds the mileage your car can get once it's warmed up. Also, as mentioned, your mileage should improve once you have 1-2k miles under your rubber. I'd say, be patient, and track the mileage per tank of gas, to see how it develops. If you can. do a few longer trips on a separate tank of gas and calculate the mileage for that tank, to see what you get there.
There is also the learning curve. My mileage has improved somewhat - or at least gotten more consistent, since I bought my Prius. I also notice that loading the car up a lot decreases my mileage substantially.
The bottom line is still, whatever your actual mileage you are doing a lot better than without HSD.
Cheers,
M

 

6.5miles with lots of stops is going to be a mileage killer for sure. Most of the folks are seeing 28-30mpg range consistantly with 'better' routes.

There's, obviously, still a lot of confusion about what the EPA numbers mean. I have an article posted here on Greenhybrid.com somewhere that discusses why you may or may not get EPA mileage. Let me just say that "city" is a very vague term. If your 'city' is exactly like the test run the EPA does you'll get 'city' mileage similar to the EPAs. One of the big complaints about the EPA mileage estimates is that their 'city' is not realistic in today's world of hard acceleration b/w frequent (every 2-3 blocks) lights and very short runs of 5-10 minutes.

Your first 5 minutes of each trip will be your worst mileage--the warm-up phase. Anything after that and you're going to be able to improve your overall mileage. In your case you're likely only driving for about 10-15 minutes before you arrive at your destination and that's just not enough to overcome that low mileage warm-up phase.

Also, let me add, that 'very slow acceleration' is NOT--i repeat-- NOT the best way to achieve good numbers. Moderate to brisk acceleration that gets you up to speed in an efficient manner then backing off as you approach your desired cruise speed is, ultimately, better. You'll eventually learn to anticipate lights and maximize coasting and gliding and that too will help.

The ICE will run, even going down hill, in the first 5 minutes...after that it usually will not unless your battery SOC has gotten very low...which is rare.