In part 1, we saw that Drexan Corporation was interested in carefully, rigorously testing the idea that nitrogen inertion can save long haul trucking companies money and help the environment. Harris Transport’s long haul trucking fleet (based in Winnipeg, Canada) was ideal for Drexan’s research, discussed next.
The long haul routes, from Manitoba to British Columbia to San Diego, covered a consistent, broad range of outdoor temperatures and elevations. The same driver ran the same vehicle, thus disentangling vehicle performance from driver behavior.
Harris Transport had a large truck fleet, enabling statistically significant testing on nearly two thousand wheel positions on 70 tractors and 117 trailers. The fleet size was similar to that in prior years, enabling a clear comparison of current to past performance, i.e. the benefits of nitrogen inertion.
Three fleet maintenance scenarios were available for comparison: lax tire pressure monitoring (2004 and prior), strict tire pressure monitoring (2005), and nitrogen inertion along with strict tire pressure monitoring (the 2006 study). In total, this covered 22 million driving miles.
Nitrogen inertion (to at least 95% purity) comprised approximately 65% percent of the fleet tires, and the remaining 35% was inflated with compressed air. The truck drivers didn’t know whether their specific vehicle or which tires were nitrogen-inerted.
West End Tire nitrogen-inerted tires randomly across tire brand, age, and so on. They also assessed tread wear as per prior arrangements with Harris Transport.
In summary, neither Harris Transport nor West End Tire employees could inadvertently bias the results. Also, there were no disruptions to the usual business routine. Therefore, any fuel economy or tire performance benefits could only be attributable to nitrogen inertion.
What were the study results? Nitrogen inertion improved Harris Transport’s long haul trucking fuel efficiency by 3.3% compared to a rigorous tire pressure maintenance program, and by 6.1% compared to no tire pressure maintenance program.
It also led to an 86% improvement in tread wear, compared to a rigorous tire pressure maintenance program. Casing failure results were inconclusive due to the small number (seven) of failures.
Harris Trucking paid $8500 Canadian dollars to inert 65% of their trucking fleet. In so doing, they saved 110,000 gallons of fuel, i.e. $425,000 Canadian dollars—much more than they paid for nitrogen inertion. There are additional, difficult-to-quantify benefits, i.e. government recommended fuel reductions, less need for tire waste disposal, shareholder value, and so on.
Drexan recommends that all long haul trucking fleets convert to nitrogen inertion, given its environmental benefits and proven ability to save businesses money. This option is also available to common consumers to more easily maintain tire pressure and save on gasoline costs.
- Mech. “Results of a trial of nitrogen tire inflation in a long-haul trucking fleet.” Compressed Air Best Practices Magazine, September 2007, 7–13, 48–49.
K. Mech. “Effects of nitrogen tire inflation on Canadian long haul trucking.” Final Report Prepared for the Freight Sustainability Demonstration Program, 12 June 2007 (revised), 27 pp.