How much fuel does a semi-truck consume while idling?

A Class 8 semi-truck consumes roughly 0.8 to 1.2 gallons of diesel fuel per hour when idling to power climate controls and electronics.

Do trailer skirts actually improve fuel mileage?

Yes. trailer side skirts redirect wind flow around the trailer tires and undercarriage, improving fuel economy by 4% to 7% at highway speeds.

Practical Strategies for Improving Fleet Fuel Economy (MPG) by 15%

The Impact of Fuel Overhead in Trucking

Fuel consumption is typically a commercial fleet's second-highest operating cost, behind only driver compensation. Heavy-duty Class 8 trucks average roughly 6 to 6.5 miles per gallon (MPG). Improving this metric by even 1 MPG yields massive annual savings across a fleet.

Three Areas to Optimize for Maximum MPG

1. Driver Behavior Modifications

The driver has the greatest impact on fuel efficiency. The main factors are:

Speed Management: Operating a tractor at 65 MPH instead of 75 MPH reduces fuel consumption by up to 12% due to aerodynamics.
Idle Reduction: Idling consumes roughly one gallon of diesel per hour. Shutting engines down when parked or using Auxiliary Power Units (APUs) prevents unnecessary waste.
Progressive Shifting: Keeping engine RPMs in the "sweet spot" (1100–1400 RPM) prevents excess fuel burn during acceleration.

2. Aerodynamic Retrofits

Air resistance represents a significant drag at highway speeds. Installing trailer side skirts, aerodynamic fairings, and gap reducers between tractor and trailer reduces wind drag, boosting fuel efficiency by 4% to 8%.

3. Tire Maintenance and Low Rolling Resistance

Underinflated tires flex more, causing heat buildup and rolling resistance. Underinflation by just 10 PSI reduces fuel economy by 1%. Low rolling resistance (LRR) tires use specialized rubber compounds to roll easier and save fuel.