Most pundits say that we can curb gas consumption by outlawing SUVs, raising CAFE (MPG) standards, and just plain driving less. Here’s what the Federal Highway Administration data says:
1) An average household vehicle is driven slightly more than 12,000 miles per year … up 8% from 1992
2) There were 235 million household vehicles in the US in 2006 (latest available FHWA data) … up 28% since 1992 … about 40% of household vehicles are SUVs, vans, trucks
3) Gas consumtion (by households) was 135 billion gallons in 2006… up 27% since 1992 … almost precisely the same as the increase in the number of vehicles on the road
4) An average car’s actual MPG is 15% better than an average SUV, van, truck’s MPG … 22.4 MPG to 19.4 MPG
5) But, an average SUV is driven 5% fewer miles annually than an average car … 11,857 miles to 12,427 miles … so an average SUV only consumes 10% more gas per year … 612 gallons to 554 gallons
6) Current CAFE standards are 27.5 MPG for cars and 20.7 MPG for SUVs … an average car on the road is getting 22.4 MPG (82% of the CAFE) … an average SUV on the road is getting 19.4 MPG (94% of the CAFE)
Bottom line: Based on the data, I don’t feel quite so guilty driving my SUV.
Keep reading for data and analysis
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Based on the latest full-year of data available from the Federal Highway Administration, U.S. households consumed over 135 billion gallons of gas 2006 — a 27% increase since 1992, and a 4.5% increase since 2002.
It’s conventional wisdom that the way to get consumption down is simply to raise CAFE standards (the MPG performance that new cars must achieve) and to get SUVs off the road. The hard data suggests a bit more interesting story than that. (See the complete data table below for details)
Cars vs SUVs
Again, fuel consumtion went up 27% from 1992 to 2006; during that same time period, the number of registered vehicles (passenger cars, vans, SUVs, light trucks) increased by 28% — from 184 million in 1992 to 235 million in 2006. In other words, the percentage increase in registered vehicles almost perfectly matches the percentage increase in fuel consumption
There’s more to the numbers, though. The mix of vehicles shifted away from passenger cars to vans, SUVs, trucks.
In 1992, cars were almost 80% of the total; by 2006 — there were almost 100 million vans, SUVs, and trucks on the road — accounting for over 40% of the total. No surprise there.
And, everybody knows that SUVs (for shorthand, I’ll just refer to the category of vans, SUVs, and trucka as “SUVs”) use more gas than cars, right?
That’s true in aggreagte — SUVs as a group do use proportionately more gas than cars, but not by much In 2006, SUVs were 42.3% of the vehicle mix and consumed 44.7% of the fuel. That’s not as much of a skew as most people think. Why is that?
Keep in mind that fuel consumption is the product of both MPG (miles per gallon) and the number of miles driven. SUVs do guzzle gas faster than cars — 19.4 MPG versus 22.4 MPG — a 15.8% difference in fuel efficiency.
But, that spread gets partially offset by the miles driven. On average, SUVs were driven 11,857 miles in 2006; cars weredriven 12,427 miles — a 5% conservation advantage to SUVs.
Note: that average miles driven by SUVs fell from 1992 to 2002 . A possible rationale is that many of them are substituting for and being used as cars, which historically have racked up lower average annual mileage.
So, an average SUV does use more gas per year than an average car, but the difference is only about 10% — 612 gallons per SUV to 554 gallons per car.
Bottom line: SUVs are bad, but not as bad as many people make them out to be — they’re driven less and the actual MPG gap has narrowed considerably (keep reading)
CAFE Standards (CAFE = Corporate Average Fuel Economy)
It’s hard to argue against CAFE standards. There may be a limit as to how high they can be pushed, but we certainly haven’t reached that point.
The current CAFE standards (27.5 MPG for cars; 20.7 MPG for SUVs) have been in place for almost 15 years. The actual fuel efficiency being achieved by the US “fleet” is 22.4 MPG for cars, and 19.4 MPG for SUVs. In other words, the fleet average for cars is only 18% below the CAFE standard; SUVs achieve actual fuel efficiency almost 94% of their CAFE standard. Why is that?
Click chart to make it bigger
Well, for openers, the CAFE standard for SUVs is lower. But, more important, there’s an age mix of vehicles in operation — some cars may pre-date CAFE standards and drag down their average. Since SUVs are relatively new to the scene, it’s seems reasonable to expect the fleet of SUVs to be newer and in closer compliance to the CAFE standards.
So what?
1) Put more vehicles on the road and you’ll consume more gas — plain & simple.
2) Most fuel usage analyses focus on MPG — specifically CAFE standards — rather than actual MPG, or better yet, gallons per vehicle (per year).
3) Sure, less fuel is consumed if people drive higher MPG vehicles and hold mileage constant — but it doesn’t look like they do — as MPG goes up, so does mileage.
4) Pre-CAFE cars may be more of a problem than SUVs . (Note: I own an SUV and I don’t drive it that much).
Click tables to make them bigger
Source: Federal Highway Administration,
Annual Statistics, Report VM-1
http://www.fhwa.dot.gov/policy/ohpi/hss/hsspubs.htm
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