We'd already discussed this but I thought this report merits another look: Quality Planning Corporation 10,500 - 2,000 = 8,500 non-hybrid driver miles 2,000 / 8,500 = 23.6% ~= 25% (Quality Planning math) Column 1 Column 2 Column 3 Column 4 Column 5 Column 6 0 miles MPG gallons Source 1 8 500 34.6 246 12 EPA user reports for 2009 Yaris automatic 2 10 500 51.6 203 17 EPA user reports for 2009 Prius automatic . So we get: 246-203 = 43 gallons extra 43 / 246 = 17% ... the Prius driver gas savings, fewer gallons burned than the Yaris Prius drivers travel 2,000 miles more than the Yaris drivers yet still burned 17% less gas. So now this quote reads a little funny: Obviously, Dr. Raj Bhat failed to count the gasoline burned and has assumed the hybrid and the non-hybrid got the same miles per gallon. Now if we use the 2008 data, the table reads: Column 1 Column 2 Column 3 Column 4 Column 5 Column 6 0 miles MPG gallons Source 1 8 500 36.1 235 38 EPA user reports for 2008 Yaris automatic 2 10 500 46.5 226 113 EPA user reports for 2008 Prius automatic . So we get: 235-226 = 9 gallons extra 9/ 235 = 4% ... the Prius driver gas savings, still fewer gallons burned than the Yaris Bob Wilson
This study shows that hybrid drivers LOVE to drive. Who says Prius is for those who hate to drive? The opposite seems to be true indeed. The 25% increase could be for multi-car families with a hybrid and non-hybrid. Hybrid would be the pick to save gas when given the choice. You also have to count the time the non-hybrid cars spend in the shop for repairs.
Ouch! Dr. Bhat also seems to assume that owning a Prius leads to (causes) one to drive farther. It also seems possible that people who buy a Prius anticipate driving farther. Since they plan to drive more, they select a Prius because excellent fuel mileage will reduce their operating expenses.
Exactly! A Prius will be my next car because I drive 75-80 miles a day (also because I just really like it as a car.) I won't increase my driving just because I drive a Prius, happy as I may be to drive it. In fact, We're looking to sell our house and move a bit closer to work to eliminate some of the driving my wife and I have to do every day. (I'll still wind up driving 50 or so miles a day.)
The report also seems to ignore the reason why Yaris owners drive less compare to Prius owners. Could this be because the fact that Yaris is a much smaller cars and it might not be the ideal for non-commute use?
Gotta think that high mileage drivers tend to gravitate towards fuel efficient vehicles. If I drove 10 miles a day, then a Hummer would be fine. The more you drive, the better the "numbers" look for a Prius.
It seems that medical researchers learned long ago that you have to adjust for the demographics before attributing any cause and effect to a statistical finding such as this. For example, if you take just the average age and income of Prius owners vs Yaris owners and then look at a wider population of people of those same ages/incomes do we find the same difference in miles traveled? Such a simple thing to do before jumping to any conclusion about hybrids cause people to drive more (which I'm sure for some people they do...but the question is by how much overall) But there is another aspect to this. What if I decide to drive from San Jose to LA instead of fly, since it is so much cheaper...especially if I have a rider or two? Another unaccounted for variable. 3PriusMike
I'm seeing two possible scenarios: 1) The people who drive hybrids have selected them because they drive more than average and thus are applying that hybrid fuel efficiency to more miles than your average driver. Good for the owner, good for the earth. 2) The people who drive hybrids begin driving more than average after getting their hybrids, realizing that they can do more in their car while still using less gas than if they selected a different car AND drove the "old" amount. Still good for the owner, still good for the earth. Maybe I'm missing other options. But neither of these seems to speak particularly well for non-hybrid cars. The conclusion of this study seems to be that it would be best for people to get cars that get decent enough mileage for their commutes but bad enough that they are discouraged from driving them unless they have to. Perhaps that's a scenario that would be healthier for people, their communities and the earth, but I don't know that the marketing folks would really be rallying behind that.
