What counts as a superload.
States set their own thresholds, but the working line sits at roughly 16' wide, 16' tall, 110' long, or 200,000 lb gross combined weight. Cross any of those four, and the move shifts from “permitted oversize” into “engineered superload”. The difference matters: a superload requires a route survey, bridge analysis, and per-state engineering review on top of the permit. It usually requires police escort. And the lead time jumps from days to weeks.
Typical superloads: refinery columns and reactor vessels, large power transformers (above 250,000 lb), gas turbines, wind turbine nacelles for utility-scale projects, prefab modular structures, and specific over-dimensional construction equipment like Komatsu PC8000 mining shovels.
Multi-axle and modular trailers.
Above 200,000 lb you stop counting deck length and start counting axles. The job is to spread the weight across enough wheels to keep per-axle loads inside state limits — typically 20,000 lb per axle on Interstate routes, lower on county roads. The math determines the trailer.
Modular trailer work is coordinated through partners we've used for years.
Engineered routing and bridge analysis.
A superload route is engineered, not picked. Every candidate path is walked through three layers of analysis:
- Bridge inventory analysis. Every bridge on the route is checked against the load's axle layout and weight distribution. State DOTs maintain inventories with structural limits per span.
- Clearance survey. Every overhead obstruction — bridge underclearance, traffic signal arms, overhead wires, sign gantries — is field-measured against the load profile.
- Road-profile review. Pavement grade, shoulder strength, lane width, signal-arm reach. For wide superloads this is the constraint, not bridges.
The output is an engineer-stamped route that becomes the legal path. Any deviation — including forced detours from construction or weather — requires re-engineering, not just a re-permit.
Police escorts and road closures.
Superloads at the top end move with police escort, not just pilot cars. Some states require state-trooper escort the entire route. Others accept certified pilot cars for in-state segments and add police only at major junctions, bridge crossings, or metro segments. For the largest moves — refinery columns, big transformers — full road closures are routine, often on a single overnight or weekend window negotiated weeks in advance.
Escort coordination is part of the bid. Cost depends on the lane, the time-of-day requirement, and whether state troopers or contract escorts are used. Quote includes it.
Lead times and scheduling.
Plan in weeks, not days. A typical superload move stacks:
- Week 1–2: Route engineering, bridge analysis, DOT pre-clearance.
- Week 2–3: Per-state permit applications, escort booking, police-coordination requests.
- Week 3–4: Permit approvals come back state by state; carrier and trailer scheduling locks.
- Week 4–6: Pre-move walkthrough, time-of-day windows confirmed, road-closure plans signed.
Once the move starts, transit is usually one to four days of actual travel — superloads don't move at night, don't move in bad weather, and rest at engineered staging points. Total ground time is short relative to the prep window.
When ocean takes over.
At a certain dimensional and weight tier, ground transport stops making sense. A reactor vessel going from a Houston fabricator to a Brazilian refinery doesn't road-haul to Brazil — it moves to the nearest deepwater port, loads onto a heavy-lift ocean vessel or RoRo, and ground- hauls only on the destination side. We coordinate the full chain: domestic superload from fabricator to port, ocean booking with the right vessel and equipment, port-clearance at the destination, and the final inland superload to site.
See ocean to Latin America and ocean to Africa for port and lane detail.
Frequently asked.
What is a superload?
A superload is the upper tier of oversize/overweight freight. Working thresholds vary by state, but the working line sits at roughly 16 ft wide, 16 ft tall, 110 ft long, or 200,000 lb gross combined weight. Above any of those, the move requires engineered routing — not just a permit.
How long does a superload permit take?
Two to six weeks is typical, occasionally longer. Engineered route surveys, bridge analysis, DOT coordination, police-escort scheduling, and per-state approvals stack on top of each other. We start the permit clock the moment the load is awarded.
What equipment moves a superload?
Multi-axle trailers — typically 8 to 13 axles depending on weight — with steerable rear axles and weight-distribution math worked out for the specific load. For refinery columns and transformers above 250,000 lb, custom modular trailers (Goldhofer, Scheuerle) are sometimes required.
Do superloads need police escort?
Yes in most cases. Police escort is standard for loads above 16 ft wide, for certain bridge crossings, for metro segments, and for full road-closure moves. Some states require state-trooper escort specifically; others accept third-party certified pilot cars in the lead role with police only at major junctions.
Why is bridge engineering required?
A superload exerts axle loads that can exceed a bridge's design rating. State DOTs maintain inventories of every bridge in the network with structural limits. For each candidate route, the bridges are analyzed against the load's exact axle layout and weight distribution. If a bridge fails the math, the route changes — or the bridge gets temporary reinforcement.