For decades now, the diesel engine has successfully pulled billions of pounds worth of freight up hill and down dale. It still does, of course, and more efficiently than anyone ever imagined it could. Given how clean diesel engines have become (ultimately running smoke-free by 2007), it’s hard to imagine anything replacing them out on the open road any time soon.

But if your work keeps your trucks close to home, you’ve got a growing list of alternatives to diesel power. They’re options now, at least. They may not be options forever, because of increasingly strict emissions rules and a sharp-edged need to diminish our dependence on foreign oil supplies.

Among trucking fleets, it’s safe to say that nobody is better prepared for the shift to alternative fuels than courier giant United Parcel Service. The company operates 77,000 trucks plus some 60,000 trailers, not to mention 500 planes. On any given day it delivers 13 million packages around the world.

Given its size, along with substantial resources and a clear sense of its obligation to experiment for the public good, UPS has become a huge test bed for freight carriers. It has about 3200 alternative-fuel vehicles running in North America (no company has more), including 735 of the familiar brown package vans in Canada-half the fleet in this country-using propane. In the United States, the company has 967 vans running on compressed natural gas. The CNG vans chop particulate emissions by 95%, carbon monoxide by 75%, and nitrous oxides by 49% compared with diesel.

Last month, UPS showcased its successes with alternative fuels at Michelin’s third annual Challenge Bibendum in Fontana, Calif. Launched in 1998 to celebrate the 100th birthday of the company’s Michelin Man mascot (his name is “Bibendum”) and to demonstrate pollution-free automotive technology, the event was the first to be held in North America (the others were in Europe).

This year, for the first time, the event included commercial vehicles. Some 200 journalists from around the world watched odd little cars compete in fuel-mileage competitions, among other trials, and had a chance to talk with dozens of engineers including some from Freightliner and Volvo who were showing off their latest truck technologies.

UPS was the largest truck fleet there, and one of its trucks on display was a tractor running on LNG, or liquefied natural gas. UPS has been testing LNG since 1994 and will have 10 such tractors operating in the Los Angeles area by next year. The advantage of LNG over CNG is its greater density, meaning it offers more energy per tank of the same size. And that makes it viable for large trucks in longer regional service. The display tractor’s regular route is Los Angeles to Las Vegas.

The downside to LNG, according to UPS maintenance vice-president Robert Hall, is that the conversion from diesel costs about $15,000 US. Financially, there is no real return on the investment; the payback is purely environmental.

That’s enough for Hall. “The emissions improvement with this LNG tractor is huge,” he says. “Being a socially responsible company, we definitely will want to run these, especially in areas like the Los Angeles basin. We have the commitment. We’re just trying to get the technology to come along, and helping to get some of the OEMs to get more involved and to build these vehicles to where they’re economically feasible.”

Hall says he’s confident the equipment will develop. The more pressing issue is the lack of distribution infrastructure for LNG. There simply aren’t many places you can go to fill up the tanks.

The latest alternative-fuel effort at UPS is a hybrid electric delivery vehicle (HEV). The package van’s standard diesel engine and powertrain is replaced with a small, fuel-efficient diesel acting as a generator for the batteries and drive motors. UPS began research on the project three years ago, and last year teamed up with PEI Electronics, a developer of hybrid electric technology for the military, to develop the prototype vehicle. It is currently being used to pick up and deliver packages at 158 locations on a 50-kilometre route in Huntsville, Ala. On-road testing will be finished in February.

At an air-pollution conference a few weeks ago, UPS chairman-elect Mike Eskew said the goal with this truck is a 50% reduction in both emissions and fuel use compared to diesel.

“Our goal with this project is to significantly reduce exhaust emissions and increase fuel economy, improve mechanical and operational reliability, and provide clean, efficient auxiliary power,” Eskew explained. “Our overall objective is to lessen our imprint on the environment.” We can only accomplish this by never being satisfied with the status quo, and by searching for ways to integrate our environmental concerns and objectives into the core of our operations,” he said. “The company feels obliged to lead the way, given its size and resources.”

Eskew called this sense of corporate responsibility “enlightened commitment.” If only, some might say, all trucking outfits were big enough (and rich enough) to be able to think the same way. For most, it’s a distant luxury-that is, at least until a mandate appears on the horizon.