News Releases

Navistar's International® ProStar™ 5.7% More Fuel Efficient Than Cascadia, Independent On-Road Testing Confirms
Results Equate to Nearly $4,000 Annual Fuel Savings Advantage for ProStar

Warrenville, IL (October 21, 2007)

New independent, on-road testing confims that International Truck and Engine Corporation’s ProStar is the most fuel efficient Class 8 truck on the road, refuting previous claims by Freightliner about its Cascadia model.

In head-to-head, on-road testing against Cascadia, conducted October 2-3, 2007, the International® ProStar™ outperformed Cascadia, yielding a 5.7 percent average advantage on fuel economy.

“As promised, we’ve sought independent, unbiased testing procedures to arrive at this claim,” said Steve Gilligan, Assistant General Manager, Heavy Vehicle Center, International Truck. “SAE testing procedures are the industry standard. The International ProStar is proven to be more fuel efficient than the Cascadia and a nearly $4,000 annual fuel savings per truck is extremely significant in today’s challenging financial climate for North American trucking companies.”

The fuel economy advantage equates to an annual fuel savings of nearly $4,000 per truck at a cost of $3 per gallon when driving 144,000 miles. That annual fuel savings is 1,300 gallons.

The testing was conducted independently at Goodyear Proving Grounds in San Angelo, Texas, using unbiased Society of Automotive Engineers (SAE) Type III testing procedures. Both the ProStar and the Cascadia were subjected to a minimum of six runs, each 41 miles in length. Using GPS technology to confirm vehicle speeds, the trucks circled the test track at 65 miles per hour. Before and after each run, fuel tanks were weighed to determine consumption.

After three valid runs, the drivers and trailers were switched between the ProStar and the Cascadia. Three more valid runs were then completed. The results of the six valid runs were averaged to constitute completion of one test segment. Those tests were repeated over two days to validate the results. The 5.7 percent fuel economy advantage posted by ProStar is the cumulative average of two days of consecutive testing.

“We were confident we would come out on top since we have designed the ProStar to be the most aerodynamic, fuel efficient Class 8 truck on the market,” said Bob Weber, Chief Heavy Truck Engineer, International Truck.

International stands by results of previous tests that demonstrated ProStar to be more aerodynamic than any other Class 8 truck being operated in North America (based on testing conducted prior to the ProStar launch). International has spent more than $1 million conducting full-scale tractor-trailer testing to SAE standards at Canada's National Research Council Institute for Aerospace Research.

Earlier this year, competitive Class 8 vehicles including the Freightliner Century, Freightliner Columbia, Peterbilt 386, Volvo VNL780 and the Kenworth T2000 were tested, filmed and the results documented. None of these vehicles was more aerodynamic than ProStar, and at least one tested as much as 14 percent less aerodynamic. Aerodynamic design has been shown to be one of the key factors that can improve fuel efficiency, consuming up to 50 percent of the engine’s usable horsepower at highway speeds.

Following in International’s continuous improvement culture for its products, future testing will include SAE Type IV testing featuring 1,000 straight miles of driving, additional wind tunnel testing, cross-country testing and additional SAE Type III testing with MaxxForce engines.

Full published results of the test are available at

Truck Brand: ProStar Cascadia
Configuration: High Rise Condo Sleeper
Engine: Cummins ISX 400 HP ST (1550/1750) DDC Series 60 455 HP (1550)
Transmission: Eaton 10-spd direct Eaton 10-spd direct
Axles: 12K Frt, 40K Rear (2.62 AR) 12K Frt, 40K Rear (2.62 AR)
Tire Brand/Model: Michelin XZA/XDN Michelin XZA/XDN
Tire Size: 275/80R22.5 275/80R22.5
Trailer Gap: 43 in. 43 in.
Test Weight 80,000 lbs 80,000 lbs

About International Truck and Engine Corporation
A wholly owned subsidiary of Navistar International Corporation (OTC: NAVZ), International Truck and Engine Corporation is a leading producer of medium trucks, heavy trucks, severe service vehicles, mid-range diesel engines, parts and service. International and its affiliates sell their products, parts and services through a network of nearly 1,000 dealer outlets in the United States, Canada, Brazil and Mexico and from more than 60 dealers in 90 countries throughout the world. Additional information is available at: