Engine and Motor Types Used by the Largest U.S. Trucking Companies
Below is a summary of the primary engine and motor types used by the 10 largest U.S. trucking companies by fleet size. Most large fleets operate a mix of diesel, gasoline, and increasingly, alternative fuel and electric powertrains. The specific engine models can vary by vehicle type and application.
| Company Name |
Main Engine/Motor Types Used |
Notable Details |
| FedEx Corp. |
- Gasoline: GM 6.0L V8, Ford 7.3L V8
- Diesel: Cummins ISB 6.7L, Cummins 5.9L ISB
- Hybrid Electric
- Isuzu 3.0L Diesel |
Operates a diverse fleet including step vans and tractors; uses hybrid and lightweight vehicles.
|
| UPS |
- Diesel: Cummins 4BT, 6BT, Navistar 444E (7.3L PowerStroke), VT365 (6.0L PowerStroke), International Diesel
- Gasoline: Chevy 4.3L, 6.0L V8
- Natural Gas: Cummins X15N 15L
- Hybrid Electric |
Large focus on alternative fuels; recently added natural gas-powered Kenworth T680s.
|
| Knight-Swift Transportation |
- Diesel: Detroit DD13, DD15
- Natural Gas: Cummins X15N 15L (RNG)
- Testing hydrogen ICE |
Testing renewable natural gas and hydrogen engines for sustainability.
|
| J.B. Hunt Transport Services |
- Diesel: Detroit DD13, DD15
- Natural Gas: Cummins X15N 15L (RNG)
- Electric: Freightliner eCascadia (pilot) |
Early adopter of RNG and electric trucks; testing Cummins X15N.
|
| Schneider National |
- Diesel: Detroit DD15 Gen5 (Freightliner Cascadia)
- Some Cummins engines |
Standardizes on Detroit engines for new trucks.
|
| Penske Logistics |
- Diesel: Detroit, Cummins, others (varies by customer spec)
- Electric and hybrid options |
Offers a range of engines based on customer needs; supports DEF and SCR technology.
|
| Ryder System |
- Diesel: Cummins, Detroit, Volvo, Mack
- Natural Gas: Cummins ISL-G
- Electric and hybrid options |
Operates a mixed fleet, including natural gas and electric vehicles.
|
| Werner Enterprises |
- Diesel: Detroit DD15, Cummins X15
- Natural Gas: Cummins X15N 15L
- Hydrogen: Cummins 15L Hydrogen ICE, Hydrogen Fuel Cell (pilot) |
Integrating natural gas and hydrogen engines for sustainability.
|
| R+L Carriers |
- Diesel: Peterbilt tractors (typically Cummins or PACCAR engines) |
Operates a large fleet of Peterbilt tractors; specific engine models may vary.
|
| Estes Express Lines |
- Diesel: Primarily Freightliner and International tractors (Detroit, Cummins engines) |
Uses standard industry diesel engines; details vary by tractor model. |
Key Trends
-
Diesel engines (Detroit, Cummins, International) remain the backbone for long-haul and heavy-duty applications.
-
Natural gas engines (notably Cummins X15N) are being rapidly adopted for sustainability, especially by UPS, Knight-Swift, J.B. Hunt, and Werner.
-
Hybrid and electric vehicles are in pilot or early adoption phases, especially for local delivery and regional haul.
-
Engine selection often depends on the specific application, region, and sustainability goals of each company.
This table reflects the most common and notable engine types in use as of 2025, but each fleet may include additional models and alternative powertrains for specialized needs.
