With 2025 coming to an end, here's a look at some of the latest heavy-duty trucks available for fleets in 2026. These vehicles all run on traditional internal combustion engines and powertrains (although some feature natural gas options).

An important note is that, unless the 2027 NOx Final Rule is delayed, MY2026 diesel trucks will be the last of their kind. With more stringent rules going into effect regarding NOx reduction and powertrain warranty life, the newer engines for '27 and beyond will have slight variations on diesel exhaust fluid dosing and other system changes, while the engines are expected to require PC-12 heavy-duty engine oils. These will lead to a cost bump, though Cummins has reported users of the 2027 X15 diesel engine will see maintenance benefits.

Daimler Truck North America

Freightliner

Daimler Truck North America (DTNA) refreshed its flagship over-the-road tractor for 2025 with the fifth-generation Freightliner Cascadia. Since its introduction in 2007, more than one million Cascadias have been sold, making it a staple for long-haul and fleet operations.

For the fifth gen, engineers and design team focused on advanced safety technology and improved aerodynamics. Aerodynamic improvements include a redesigned hood, A-pillar deflector, three-piece front wheel well closeouts, hood-to-bumper seals, and new bumper air ducts that direct airflow around the underbody and tires. These refinements deliver a 1.9% improvement in fuel efficiency compared to the previous model, according to Freightliner engineers.

Available in both large and small cab configurations, the new Cascadia integrates DTNA's Detroit Connect telematics platform for performance monitoring and a broad suite of advanced driver assistance systems (ADAS). For instance, witht he Attentive Driver Porotection feature, if the driver is unresponsive due to a medical issue while lane keep assist is activated, the truck will slow to a stop, activate the hazards, unlock the doors, and turn on the dome light.

Check out our video walkthrough below for a look at some of these changes:

Like previous models, the new Cascadia offers a wide array of engine options, including the Detroit DD13 and DD15 and the upcoming addition of the Cummins X15N. This 15L natural gas engine offers between 400 and 605 hp and 1,450 to 2,050 lb.-ft. of torque.

Western Star

Western Star Trucks enters 2026 with three X-series models: 47X, 49X, and 57X. Designed to accommodate a range of engines and transmissions, each model is equipped with a Detroit Assurance suite of active safety systems and available in two trim levels: Base and Premium.

The 47X is the shortest configuration in the series, with a bumper-to-back-of-cab (BBC) length of 111.6", and is built for vocational applications like concrete mixing and dump truck work. The 47X is powered by a Detroit DD13 engine, offering durability and performance in extreme conditions, which the company says makes it ideal for snow and ice removal.

The 49X adds 10" of length over the 47X and features efficient air filtration, higher horsepower and torque, and extended sleeper cab options, making it suitable for longer-haul applications.

The 57X is the highway-focused model and closely mirrors its Daimler Truck relative, the Freightliner Cascadia, with the longest BBC length in the series.

International

International Motors has worked to diversify its heavy-duty lineup over the past year with the International S13 Integrated Powertrain, now available in the LT, RH, HX, and HV series trucks. Certified for renewable diesels, such as R100, R99, and hydrotreated vegetable oil (HVO), the platform gives fleets a cleaner-burning alternative that works seamlessly in existing S13 diesel engines while reducing carbon emissions, according to the OEM. The Integrated Powertrain comprises an engine, T14 transmission, and aftertreatment system and offers up to 515 hp and 1,850 lb.-ft. of torque.

Unlike biodiesel, R100 is a paraffinic fuel with no oxygen compounds, providing better cold-flow properties and a higher cetane number for a cleaner burn, making it a high-quality, low-carbon alternative to conventional diesel.

The over-the-road flagship model, the International LT, is built for long-haul operations, but its five cab configurations make it suitable for agile urban or drayage operations. Bendix Fusion collision mitigation technology further enhances safety inside and outside the truck.

Paccar

Kenworth

Kenworth Trucks continues to update the T680, its flagship over-the-road tractor, with expanded powertrain and safety options. After adding cleaner engine options in 2024, like the Cummins X15N and parent company Paccar’s CARB-compliant MX-13, the OEM created three new ADAS packages: ADAS, ADAS Pro, and ADAS Premier.

The three options integrate the latest Bendix Fusion features, including a forward-facing camera that supports adaptive cruise control with Stop and Auto-Go, pedestrian-sensing autonomous emergency braking, and high-beam assist. The system also includes lane departure warnings, highway departure braking, and blind spot detection.

Higher-tier packages add real-time tire pressure monitoring, lane-keeping assist, torque-assisted steering, and Kenworth’s DigitalVision Mirrors, which replace traditional mirrors with HD cameras and in-cab displays.

The Paccar TX-12 Pro automated transmission can also now be paired with the Paccar MX-13 engine in the T680, T880, and W990, which the OEM says enhances vocational and select off-highway applications.

Peterbilt

Peterbilt Motors has made the Paccar TX-12 Pro automated transmission available across its heavy-duty truck lineup of models 579, 567, and 589. Built on the TX-12 foundation and paired with the MX-13 engine, the new transmission-engine powertrain improves both off- and on-highway applications, according to the OEM. 

For vocational fleets, the Model 567 introduces a new front-frame equipment mounting provision, which the company says provides a robust framework to support accessories like snowplows, hose reels, or outriggers. A sloped hood design also improves visibility and creates a more aerodynamic profile, resulting in improved fuel efficiency.

The long-haul flagship Model 579 adds Bendix Fusion’s Stop and Auto-Go capability, which uses a forward-facing camera to enable automatic emergency braking, pedestrian detection, and active cruise control with braking, which automatically resumes motion in traffic, helping reduce driver fatigue in congested conditions.

The Model 589, Peterbilt’s premium work truck, receives updated LED pod headlights that consume 30% less power than halogen bulbs while providing maximum light output, including 45-degree left and right low beams.

Volvo Group

Mack

Mack Trucks used its 125th year in business to refine its Class 8 over-the-road offerings with a new line of long-haul tractors and renewed focus on regional operations. 

Revealed in early 2025 and designed for long-haul, the Pioneer emphasizes aerodynamics, fuel efficiency, and driver comfort. It is powered by Mack’s MP13 engine and delivers up to 455 hp and 1,900 lb.-ft. of torque. Mack’s most connected truck in history, the Pioneer comes standard with Mack Connect telematics, which the OEM said will help drivers improve behavior and keep fleets ahead of maintenance and software updates.

The OEM also showed off a redesigned Mack Anthem for regional haul and city-focused applications, with a shorter bumper-to-back-of-cab (BBC) length of 113.5", which is 12" shorter than the Pioneer. This improves maneuverability in tight spaces. Available in day cab, 44-inch sleeper, and 64-inch sleeper configurations, the Anthem maintains the same interior cab space as the Pioneer to reduce driver fatigue and support long shifts.

Volvo

Volvo Trucks North America (VTNA) introduced the all-new Volvo VNR, a Class 8 regional haul tractor built on the same platform as the OEM’s refreshed 2024 VNL long-haul model. The VNR features a tighter turning radius, enhanced visibility, and a more rugged design than its predecessor to make it ideal for urban applications, while still offering optional sleeper configurations for longer runs.

The VNR carries over the 24V electrical architecture from the VNL, enabling faster diagnostics and lighter components, according to the OEM. Fuel efficiency is improved by 7.5% thanks to a redesigned cab, aerodynamic enhancements, and the new-generation Volvo D13 VGT engine.

Advanced safety systems include Volvo Active Driver Assist, optional dynamic steering assist, a mirrorless camera monitor system, and more. Day cab models can also be equipped with a short-stop parking heater, providing cab heat without idling. The OEM says these safety and maneuverability features make the VNR well-suited for fleets operating in pedestrian areas.