FleetSmart Profiles: Highway Trucking

Northern Resource Trucking Ltd. – Saskatoon, Saskatchewan

Central Tire Inflation Technology Allows Bigger Payloads

Northern Resource Trucking Ltd. (NRT) is one of several companies in Saskatchewan that are using central tire inflation (CTI) technology to carry heavier payloads on secondary highways than provincial regulations normally permit. NRT's equipment paid for itself in less than one year through reduced fuel, maintenance and labour costs – and now saves the company about $50,000 a year.

Secondary highway system presents a payload challenge

Saskatchewan's major resource industries – agriculture, mining, petroleum and forestry – rely heavily on truck transportation to move their products to markets. Often, these industries are located in isolated areas of the province and accessed only by gravel or surface-treated roads that were not built for heavy-duty hauling.

Such is the case for the remote northern mines serviced by NRT. These mines are located at the end of a long series of thin-paved and gravel roads. Most of the roads are classified as secondary highway and have a maximum gross vehicle weight (GVW) of 54 500 kilograms. This gives the company a payload problem, since many of the vehicles used on these routes, if fully loaded, would exceed the GVW.

In 1998, NRT sought permission from Saskatchewan Highways and Transportation to test a potential solution – CTI technology. CTI enables a vehicle's tire pressure to be increased or lowered from the cab while travelling at any speed, effectively allowing the driver to change the "footprint" of the tires to suit the load and road conditions. Lower tire pressures result in a larger footprint, a smoother ride and, most importantly from a payload perspective, less damage to the road.

Under the department's Transportation Partnership Program, trucks using CTI equipment may be permitted to haul payloads that would normally be restricted to primary roads on secondary highways. For a typical eight-axle, B-Train configuration, this increases the allowable payload by 8000 kilograms.

The Lloydminster-Key Lake run

NRT chose its twice-per-week run to deliver liquid sulphur from Lloydminster to the Key Lake mine in northern Saskatchewan as a test route for CTI technology. The run is serviced by a nine-axle, B-train tanker unit (owner-operated) with a maximum GVW of 72 500 kilograms on the primary highway system. The most direct route for the Lloydminster-Key Lake run is 684 kilometres, but parts of this route have a 54 500-kilogram GVW limit. The alternative route is significantly longer, but allows the full 72 500-kilogram GVW.

Saskatchewan Highways and Transportation agreed to allow the rig, equipped with CTI, to carry the maximum payload over the shortest route – a measure that reduced the total travelling distance by 400 kilometres per round trip. Working with provincial officials and the CTI equipment supplier, NRT determined the best tire pressure for each segment of the 684-kilometre route. On secondary roads, the driver lowers the tire pressure to 60 to 65 pounds per square inch or even lower when the tanker is empty. Then the driver increases it to a normal pressure of 85 to 90 pounds per square inch on primary highways – without leaving the cab.

Payback in less than one year

The CTI equipment used by NRT is a two-zone system that allows the drive axle tires to be controlled separately from the trailer tires. Thus the driver can lower the drive axle tire pressures to improve traction in either poor driving conditions or emergency situations without affecting trailer tire pressures. NRT also chose a high-capacity compressor, as well as two air dryers to ensure that moisture and lubricants do not contaminate the system.

The total installed cost of the CTI equipment on the nine-axle tanker was $38,000. Based on two return trips per week, the technology has reduced the vehicle's travel distance by about 40 000 kilometres per year. This saves about $50,000 in fuel, maintenance and labour cost. In other words, the simple payback for the equipment is less than one year.

Impressive fuel savings and other benefits

NRT officials estimate that the use of CTI technology on the Lloydminster-Key Lake run saves the company about 19 000 litres of diesel fuel per year. The CTI technology has slightly improved fuel economy (54.3 litres per 100 kilometres on the Lloydminster-Key Lake run, compared with the fleet average of 58.9 litres per 100 kilometres). Still, the biggest savings have come from reducing the number of trips needed between the two locations. That's because CTI allows for a 60 percent increase in payload (from 29.6 tonnes without CTI to 47.5 tonnes with CTI) on the shortest route between Lloydminster and Key Lake.

After some initial apprehension about the CTI technology, Roger Olyowsky, General Manager of NRT, has become a believer. Although a downturn in the uranium mining industry has reduced the demand for liquid sulphur, Mr. Olyowsky says that CTI will definitely be considered for other trucks when business rebounds.

Increased payload and lower fuel and labour costs are only some of the benefits offered by CTI technology. For example, Mr. Olyowsky notes that reducing tire pressures has improved the ride for trailers, particularly when they are empty. This, in turn, has reduced damage and repair costs and extended the life of trailers, which normally take a severe beating on rough roads. The improved cab ride and better traction provided by lower tire pressures is also reducing driver fatigue and improving safety. Mr. Olyowsky estimates that tires last 25 percent longer with CTI (due to less damage from stone drilling, chipping and punctures), although there appears to be additional wear on the rims. Replacing the rims (at an estimated cost of $4,000 for aluminum rims) every few years would have a minimal impact on the overall savings delivered by CTI.

After four years of operation, the CTI-equipped truck has experienced no significant maintenance or operational problems. NRT has budgeted $1,000 per year for maintenance of the CTI equipment, but has never had to spend the full amount. It also seems that the CTI equipment will outlast its estimated five-year life.

The future of CTI in Saskatchewan

Saskatchewan Highways and Transportation is continuing to work with shippers, carriers and CTI equipment suppliers to determine how to best use this technology. Today, CTI is used in the forestry, agriculture, petroleum and mining sectors in Saskatchewan. Companies using the technology are generally satisfied with the performance of the equipment and the resulting economic and operational benefits. However, the capital cost of the equipment, which ranges from $25,000 to $35,000 per truck, continues to be a barrier.

From the transportation department's perspective, CTI is definitely reducing damage caused by heavy-duty vehicles on gravel and thin-paved roads – and that means lower road construction and maintenance costs for the provincial government. However, the impact of CTI on other road types and conditions is not yet known and is the subject of additional research.

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