The step deck trailer — also called a drop deck — solves a specific problem: freight that is too tall for a standard flatbed but does not require the full well depth of a double drop or the roll-on access of an RGN. By dropping the rear deck section approximately 18–20 inches lower than the front section (which sits over the tractor's fifth wheel), the step deck creates a lower platform for taller cargo while staying within the federal 13 ft 6 in height limit without a permit. The geometry of a typical step deck has a short upper deck (10–11 ft) connecting to the tractor's fifth wheel at the standard ~5 ft height, then a step down to a lower deck (37–40 ft) that sits approximately 3.5 ft above the ground. This lower deck position allows cargo up to roughly 10 ft tall to be transported legally, compared to about 8.5 ft on a standard flatbed. Step decks are particularly common in construction and heavy equipment industries. A skid steer loader, compact excavator, or medium-duty generator that stands 9 ft tall would exceed flatbed height limits but fits comfortably on a step deck lower deck. The open-deck design still accommodates side, rear, and overhead loading — the same flexibility that makes flatbed essential for awkward freight. Cargo securement on step decks follows the same FMCSA 49 CFR Part 393 standards as standard flatbed, with additional attention needed at the deck transition point. Equipment and machinery loads typically use chains and binders rated for the load weight, with additional blocking to prevent rolling on wheeled equipment. Oversize permits are still required when cargo exceeds legal height (13.5 ft), width (8.5 ft), or length limits, or when gross vehicle weight exceeds 80,000 lb.
| Typical length | 48–53 ft overall; upper deck typically 10–11 ft, lower deck 37–40 ft |
| Typical width | 8.5 ft (102 in) |
| Typical height | Upper deck ~5 ft above ground; lower deck ~3.5 ft above ground — allows cargo up to approximately 10 ft tall on the lower deck within the 13.5 ft legal limit |
| Payload capacity | Up to 48,000 lb |
New step deck trailers typically range from $25,000–$45,000. Per-mile rates are generally comparable to or slightly above standard flatbed rates, reflecting the specialized application.
Approximately 10 ft on the lower deck without an oversize permit, given that the lower deck sits about 3.5 ft above ground and the legal maximum total height is 13 ft 6 in. Exact usable height depends on the specific trailer's deck height. Always measure cargo and confirm with the carrier before booking.
Not directly — step decks require ramps or a crane to load wheeled equipment. The deck drop creates a step that prevents drive-on access from ground level. If cargo must be driven on under its own power (excavators, dozers), an RGN (Removable Gooseneck) is the appropriate equipment.
A step deck has one deck drop, creating an upper and lower section. A double drop has two drops — front and rear ramps — creating a low center well. The double drop well sits even closer to the ground (typically 18–24 in), allowing cargo up to about 11.5 ft tall without an oversize permit. Double drops are used when step deck height clearance is insufficient.
Yes. Many step deck trailers are built with removable or foldable ramps at the rear that allow low-clearance wheeled equipment to drive onto the lower deck. Ramp-equipped step decks are common for agricultural and construction equipment that can self-propel at a modest incline but not from grade level.
Weight should be concentrated on the lower (longer) deck section for optimal axle distribution. Placing very heavy loads on the short upper deck section near the fifth wheel can cause front steer axle overloading. Carriers and drivers will typically calculate axle weights before accepting heavy equipment loads.