USA Today article gives Prius bad mileage image

[driveprius]

I happened to stumble upon a USA Today article:

http://www.usatoday.com/money/autos/2004-0...vs-hybrid_x.htm

that pitted a VW Jetta Diesel against a Toyota Prius. The Jetta won by averaging 44 mpg. The Prius was measured at an unusually low 38 mpg, all done in the summer and all done on the highway. The article goes on to mention the computer did show an average of 51.7 mpg. The give away that something was awry was that the article mentioned being able to fill up to 11.1 gallons of gas at a gas station. Filling up your tank all the way is a rarity.

The Toyota vice president did comment that there was a good chance that USA today failed to fill the tank at the start of the trip but were able to fill it at the end of the trip and so the mileage appears much lower than what the computer shows. Toyota commented that the computer is almost 100% accurate.

Despite this fact the article concludes that the Jetta gets better mileage than a Prius because 44 mpg is better than 38 mpg. Which pretty much restates the fact with the Prius you can't rely on the standard technique of counting how many gallons to fill up the tank because you can never be sure. In general it's just best to stick to the computer estimate of mileage.

[Kiloran]

Originally posted by driveprius@Nov 30 2005, 01:07 AM
In general it's just best to stick to the computer estimate of mileage.

[snapback]163536[/snapback]

For an article like this I wouldn't believe the computer.
The most reliable way of calculating mileage is to divide miles driven by gasoline consumed.
Because of the bladder tank, for a Prius, this should be done over the course of at least 3 tanks "full".

[ABC12]

38 MPG, all highway, in the summer. ya, right. was it a 90 MPH 1 mile trip in siberia?

ya gotta be kidding. major malfunction, total incompetence, or extreme conditions...

[DaveinOlyWA]

the article is nearly a year and a half old, reposting it will not give it anymore creedence

[john1701a]

Originally posted by Kiloran@Nov 30 2005, 12:15 AM
For an article like this I wouldn't believe the computer.

[snapback]163545[/snapback]

I have over 104,000 miles of personal data showing the computer can be trusted, coming very close to actual MPG every single time I fill with more than 4 gallons.

To be off by almost 14 MPG is absolutely absurd.

Of course, their results are way too low anyway. Cruising on the highway during the summer results in high 40's for me. And if the wind is right, low 50's. Getting 38 MPG is hard to believe no matter how they measure it.

[mikepaul]

Too bad reviewers aren't aware of the bladder problems. They should add their own fuel-flow meter to every car they test so they have apples-to-apples results. Back in the day, if one wanted to add a trip computer to a car, a fuel-flow meter was included. If they can't afford to mod the car for a while, maybe the quality of their reviews isn't moving enough magazines...

[john1701a]

It doesn't really matter. The test was rather blatantly setup to favor the diesel anyway, since they do best on the highway.

Had it been a mix of driving, rather than highway only, the Prius would have really shined... despite their filling mistake. Slowing down causes an efficiency loss for the diesel. Slowing down causes a rather impressive efficiency gain for Prius.

Imagine if no one ever had to deal with a daily stop & slow commute. Highway cruising alone is not an option in the real-world.

[ez2bgreen]

There's a lot of bad information being disseminated in the media. Yesterday, KCNC, Denver's CBS affiliate, stated that it would take years to recoup the additional cost of the hybrid system through gas savings, even after tax breaks were factored in. Apparently, they didn't do their research on tax breaks. Between the generous 85% (of the differential cost) tax credit Colorado offers and the federal tax deduction, the increment cost of the hybrid system is more than covered in the first year. That means savings begin accruing immediately, not after many years, as KCNC alleged. Of course, not all states are as generous as Colorado.

[ez2bgreen]

I've seen discrepancies as large as 11 mpg between the computer and the fill calculation. In that case, the fill (59 mpg) exceeded the computer (48 mpg). More often, the computer is higher (av. 49.2) vs. fill (av. 48.6). I rely on the computer as a better indication of per-tank mileage (standard deviation = 2.6). SD for fill-ups is 4.4. But in the long term, the average fill-up calculation probably is more accurate. <_<

I read somewhere (can't remember the citation) that the magazine's test drivers accomplished something I thought impossible. They managed to drive 700 miles on a tankfull. While that may be technically feasible (60.3 mpg), I have never gone more than 430 miles between fill-ups. And I waited until the idiot light started flashing. Because of the adverse consequences of running out of gas, I never drive more than a few miles after the gauge starts flashing.

[Jaguar88]

We should all be on the Prius gets shitty milage bandwagon and the EPA can't be trusted. That way when they try and add the Hybird tax we can argue it should be lower.