New EPA MPG Estimates on Hybrids

The EPA has recently revamped their fuel economy ratings. The old tests were criticized for being outdated and just not very good at measuring what people were getting in 'real world' driving conditions. So, in 2008, all new vehicles will be rated using this new system.

The big question is, how are these new ratings going to affect hybrid cars? Most analysts predicted hybrids would be hit harder than other car segments. But first, let's see what the EPA has changed about their rating system.

The new rating system takes into account

• Faster Speeds and Acceleration
• Air Conditioner Use
• Colder Outside Temperatures

MPG estimates will also be adjusted downward to account for factors that are difficult to replicate in a laboratory, such as

• wind and
• road surface resistance.

The FDA has set up a new site where you can view the changes in mpg ratings for individual vehicles if the new mileage tests were to be applied to the old cars.

When I looked at how the new ratings would be applied to hybrid cars, I saw a 10% to 18% drop in fuel economy ratings (See table at the end of this post for New EPA MPG Estimates on 2007 Hybrids). This rate of change seems to be consistent whether you are talking about full hybrids or mild hybrids. Although, it's interesting to note the two cars with the most to lose (Prius and Civic Hybrid) did drop the most percentage-wise.

But, it seems that most cars are seeing about that much change. As you can see, I looked up the Toyota Corolla and Camry (non-hybrid, automatic, 4 cylinder), and both cars dropped 12% and 11%, respectively. According to GreenCarCongress, all cars will see some drop in their ratings, from 8% to 30%

Compared to today’s estimates, the city mpg estimates for the manufacturers of most vehicles will drop by about 12% on average, and by as much as 30% for some vehicles. The highway mpg estimates will drop on average by about 8%, and by as much as 25% for some vehicles.

But it looks like hybrid cars can still claim top position, especially over their conventional counterparts (gas only, same type), which are seeing just as big a drop, percentage-wise. The fuel economy improvement is slightly lower than it used to be, but that difference really is slight.

One other thing to keep in mind. Despite the drop in ratings to indicate a more 'real world' estimate, individuals are still going to see their mileage vary from these ratings. Some will continue to see higher (see hypermilers), while others will see lower (see your 16 year old cousin who just got his/her license).

New EPA MPG Estimates on 2007 Full Hybrids
Make	Model	Old/ New	City	Hwy	Combined	% Dropped
Toyota	Prius	Old	60	51	55	16%
		New	48	45	46
Toyota	Highlander Hybrid 2WD	Old	32	27	29	10%
		New	28	25	26
Toyota	Highlander Hybrid 4WD	Old	31	27	29	10%
		New	27	25	26
Toyota	Camry Hybrid	Old	40	38	39	13%
		New	33	34	34
Ford	Escape Hybrid 4WD	Old	32	29	31	13%
		New	28	27	27
Ford	Escape Hybrid FWD	Old	36	31	34	12%
		New	31	29	30
Lexus	RX 400h 2WD	Old	32	27	29	10%
		New	28	25	26
Lexus	RX 400h 4WD	Old	31	27	29	10%
		New	27	25	26
Lexus	GS 450h	Old	25	28	26	12%
		New	22	25	23
Mercury	Mariner Hybrid 4WD	Old	32	29	31	13%
		New	28	27	27
Honda	Accord Hybrid	Old	28	35	31	13%
		New	24	32	27
Honda	Civic Hybrid	Old	49	50	51	18%
		New	40	45	42
Mild Hybrids
Saturn	Vue Hybrid	Old	27	32	29	10%
		New	23	29	26
Chevy	Silverado Class 15 Hybrid 2WD	Old	18	21	19	11%
		New	16	19	17
Chevy	Silverado Class 15 Hybrid 4WD	Old	17	19	18	11%
		New	15	18	16
Comparisons
Toyota	Corolla (Automatic, 4 Cyl)	Old	30	38	33	12%
		New	26	35	29
Toyota	Camry (Automatic, 4 Cyl)	Old	24	33	27	11%
		New	21	30	24