Information released from studies conducted by the U.S. Department of Energy's Argonne National Laboratories on the effects of speed and idling is extremely important to fleet owners and operators of commercial trucks.
Effect on Engine:
Careful analysis of the road experience indicates the ideal speed for the average truck is 50-55mph, the power required to increase speed multiplies dramatically:
73% more horsepower to cruise at 60mph
159% more horsepower to cruise at 70mph
Effect on Fuel Cost:
Research indicated that each mile per hour above 50 mph increases fuel consumption by 1 1/2 percent. A truck, which averages 8 mpg at 50 mph, will average 6.8 mpg at 60 mph.
Effect on Tires:
Heat is the number one enemy of tires. Sustained speeds raise tire temperatures above the critical level causing strength and wear properties to deteriorate rapidly. Tire wear will almost double at road speeds of 70 mph or greater.
Effect on Maintenance Cost:
Gears, bearings, clutches, suspension and drive trains all wear much faster at higher speeds. Increasing speed from 50 mph to 60 mph increases maintenance cost by 38%. Increasing the speed to 70 mph increases the cost by 80%.
Effect on Idling:
Idling causes twice as much damage as driving. One hour's idling is equivalent to between 80 and 120 minutes of driving time. The resulting loss of fuel economy from excessive idling can add up to 800 gallons of fuel annually for the average truck.
Effect on Accidents:
Approximate stopping distances, including reaction time for the average person (2 axle trucks) are listed below:
• @ 50 mph - 275 feet (.92 football fields)
@ 60 mph - 375 feet (1.25 football fields)
@ 70 mph - 500 feet (1.67 football fields)
