Saf-T-Liner® HDX. Ideal weight distribution for the long haul.

School bus routes come in all shapes and sizes: short and hilly, long and bumpy or all of the above. The Saf-T-Liner® HDX from Thomas Built Buses is built to handle them all. This model is designed to keep drivers comfortable, with features like standard tilt and telescoping steering wheel and optional adjustable pedals. It offers a pleasant ride for up to 90 passengers with air conditioning, coach-style seating and heavy-duty shock absorbers. And because safety is important to everyone, each HDX school bus meets or exceeds FMVSS and CMVSS. Finally, to help you keep your HDX buses safe, efficient and comfortable, Thomas Built developed one of the most extensive dealer networks in the industry.

Passenger Capacity

  • Up to 90


  • Detroit® DD8™ 260-300 hp
  • Cummins® B6.7 220-300 hp
  • Cummins® L9 260-300 hp
  • Cummins® L9N 250-280 hp


  • 181″, 209″, 238″, 267″, 277″


  • Zonar V4 advanced telematics system
  • Detroit Connect® available on DD8 engine
  • Cummins® Zonar OTAir™ – 2017 or newer


  • Up to 36,200 lbs.


  • Ergonomic driver’s dash and switch panel
  • Easy-to-read offset gauge cluster
  • Tilt and telescoping steering wheel
  • Suspended brake and accelerator pedals
  • Foot rest
  • Up to 50-degree wheel cut
  • Sound isolator over engine
  • 78″ headroom

Decade after decade, Thomas Built Buses has followed one simple philosophy: design and build the kind of school bus we’d want our own children to ride in. It’s a simple idea and it works. Passenger safety is our number one priority and every bus we manufacture meets or exceeds all FMVSS and CMVSS for school buses.

  • Meets or exceeds FMVSS/CMVSS
  • Roof bows extend to bottom of side panels
  • Double rear bumper with exterior contoured steel bumper
  • Double-bolted body mounting clips
  • Fuel tank mounted between frame rails
  • Wheelchair lift
  • Adjustable pedals
  • Air suspension driver’s seat
  • Air ride suspension
  • Heated driver’s seat
  • Front and rear bulkhead air conditioning
  • AM/FM radio, CD player and PA system
  • Remote controlled heated mirrors
  • Reading lights
  • Variety of seating options:
    • Bench seat without belts, with lap belts, with 3-point belts
    • Integrated child seat
    • Coach-style seat
  • Child reminder system
  • Interior LED lighting packages
  • Acoustical ceiling
  • Underbody pass-through storage area
  • Overhead book racks
  • White roof
  • Tinted windows
  • Staggered passenger seating

Power and performance? Yes and yes.

The Detroit DD8 is a 7.7L in-line 6-cylinder medium-range engine that boasts a horsepower range of 260-300HP and a torque range of 660–860 foot-pounds for the Saf-T-Liner HDX. Unlike on-highway engines repackaged for medium-duty applications, the DD8 engine is a clean-sheet design, built from the ground up specifically for the medium-duty cycle to deliver the best in efficiency, durability and clean performance. The DD8 engine also features leading-edge technology, including variable exhaust cam phasing which reduces driver interactions with regen. The DD8 is available with Detroit Connect Virtual Technician®, a subscription-based remote diagnostic service (free for the first five years) that instantly transmits data to the Detroit Customer Support Center, allowing you to make informed service decisions within minutes of an issue.

Lower total cost of ownership. High performance. Demand it all—and get it—with the DD8 engine.


  • The longest service intervals in the industry, with up to 45,000-mile* oil and fuel filter change intervals
  • Maximum uptime with unsurpassed efficiency and exceptional endurance
  • Power, performance and best-in-class fuel economy and reliability
  • Easier serviceability with top-load oil and fuel filters
  • Standard warranty covers the engine and aftertreatment for five years/100,000 miles/160,000 km (whichever comes first), including 100% parts and labor
  • Extended coverage options available
  • Variable exhaust cam phasing which allows additional heat to the exhaust stream to promote efficient operation of the aftertreatment system in low speed and stop-and-go operation. This reduces the need for active regen
  • Adherence to emissions regulations through 2020

*Or 12 months or 1,500 hours, whichever comes first

Learn more about how Thomas Built Buses and Detroit Diesel Corporation are partners in performance.

  • Exterior electrical access door
  • Streamlined electrical center for easy identification and access
  • Accessory module for customer aftermarket component hookup
  • Fuse relay centers provide circuit protection and easy diagnostics
  • Front access panel
  • “S” shape drop-frame design at engine location
  • Engine compartment accessible via three doors plus access panel
  • DD8 engine available with Detroit Connect Virtual Technician remote diagnostic service to help you maximize uptime
  • Easy access to fluids
  • In-dash fault code display
  • Lights equipped with plug-in connectors
  • Large two-piece curved bonded windshield
  • Exterior mirror cluster with flat and convex rearview mirrors and front crossover mirrors