To the ordinary folk out there, we probably don’t look very good when we crow about breaking the nine-mile-per-gallon barrier. Compare a Toyota Prius at something like 57 MPG to, say, a Cadillac Escalade at around 13 MPG, and the villain is obvious. Now stand up at your local Sierra Club get-together and yell, “hey, I get nine miles-per-gallon,” and see what happens.

Because of our comparatively low MPG numbers, I think trucks are often viewed as worse polluters than cars.

What few people take into account in measuring fuel economy is the amount of work we manage to accomplish with a gallon of fuel. On one level — in terms of trucking’s contribution to the national economic picture — trucks don’t go joy riding on Sunday drives in the country, or burn fuel to ferry one person to work dozens of miles in each direction. We haul freight around, generating revenue for ourselves and for the people we haul for, and all that shows up as a contribution to the GDP. A very high percentage of the fuel we burn is put to good use.

On another level — gallon-to-gallon efficiency comparisons — diesel is a more efficient fuel than gasoline, and in the long run produces fewer tons of CO2 per mile driven per gallon. According to the U.S. EPA (www.fuel economy.gov) a diesel-powered Volkswagen Jetta will travel 36 percent more miles on a single tank of fuel than the gasoline powered version. The diesel uses nearly two fewer barrels of oil and emits one less ton of GHG emissions over a year.

As a group, cars and light trucks account for 35 and 37 percent respectively of the total GHG emissions from vehicular internal combustion engines. Trucks and buses were responsible for only 19 percent. The EPA also says that of all CO2 emissions coming from the consumption of petroleum products, gasoline accounts for 60 percent, while diesel fuel accounts for 22 percent.

Now here’s the kicker; when you measure the work a truck does with a gallon of fuel, compared to what a car or light truck does, we make something like 10 times better use of the fuel than they do. When was the last time you heard that come up in a conversation?

For example, a typical 5-axle combination, 80,000 lb GVW, gets something like 280 ton-miles out of a gallon of fuel at 7 MPG. A 138,000-lb Super-B train gets 350 ton-miles per gallon at 5 MPG. Compare that with our Cadillac Escalade, which I figure makes no more than 24 ton-miles per gallon at 12 MPG.

Who’s the real fuel economy leader here?

While the trucking industry pleads with government for more latitude in size and weight regulations, tax incentives for idle-reduction technology, and infrastructure improvements for more efficient movement of goods, automobile makers are balking at mandated fuel economy improvements because they say the public won’t buy. The same public, I say, that’s all over trucking because of our perceived contribution to global warming.

Back in 2000, the Clinton administration announced the 21st Century Truck Initiative, a research partnership to develop more fuel-efficient vehicles. Among other things, the plan called for a doubling of heavy truck fuel economy by 2010.

Among the truck and engine designers I’ve spoken with recently, there’s a feeling that we might have achieved close to that if our attention hadn’t be focused on meeting EPA 2004 and 2007 emissions reduction targets.

Those restrictions cost us in terms of fuel economy, but they will have achieved a nearly complete elimination of NOx and soot emissions from big diesels by the same date. Unfortunately, nothing’s been done to reduce GHG emissions. CO2 production is directly related to fuel consumed (1 USG gasoline equals 19.4 lb (8.8 kg) CO2; 1 USG diesel equals 22.2 (10.1 kg) CO2).

If we’re to see significant improvements in fuel economy (MPG), we’ll have to radically change our idea of what a truck looks like. Trailer aerodynamics are showing a great deal of promise, and it’s ­estimated that we could bump up MPG by 20 percent (about 2 MPG) by improving air flow around our trailers.

However, if we were able to accomplish even more work with our lowly gallon of diesel fuel, we’d still achieve those targets, when considered in terms of ton-miles-per-gallon. If the politicians had the stomach for tri- or quad-axle LCVs, or triple B-train combinations, we might get our ton-mile-per-gallon numbers up into the 400 range. We’d be doing something to get 360 tm/gal out of a 5-axle at 9 MPG. Whaddya say to that, Mr. Big Fat 24 tm/g Escalade?