Oversize Load Permit

When you need an oversize or overweight permit 

In practical terms, you need an oversize or overweight permit any time your vehicle or combination exceeds legal size or weight limits for the jurisdictions you travel through. At the federal level, the commonly referenced thresholds are 80,000 lb gross vehicle weight, 20,000 lb on a single axle, and 34,000 lb on a tandem, applied alongside the Federal Bridge Formula to protect infrastructure. States administer permits and may impose additional routing or timing constraints even when you comply with the federal baseline.

Because limits and definitions vary by state and, at times, within counties or municipalities, compliance is not “set and forget.” The same load may move permit-free on one corridor but require a route-specific analysis across a state line. As a result, we treat the jurisdiction, not the load spec alone, as the trigger for permit strategy.

Permit types & when to apply 

Permits typically fall into a handful of categories:

In my workflow, I start with the load’s non-divisible status, confirm axle spacings, and then map candidate permits by jurisdiction. When the same corridor is moved frequently, we evaluate whether an annual option will lower total cost of compliance over time.

Oversized components like turbine sections or construction modules typically qualify as non-divisible and obtain route-conditional approval when infrastructure can accommodate the move, as assessed by the state.

Data and documentation you will be asked for

Most permitting delays come from incomplete data. Before you request a permit, assemble the following:

• USDOT/MC numbers and carrier information
• Vehicle and trailer configuration (type, axle count)
• Axle weights and axle spacings (center-to-center)
• Overall dimensions: height, width, length; overhangs if applicable
• Origin, destination, and proposed route (or route constraints)
• Requested dates/times and any escort arrangements
• Contact details for dispatch and driver

This list mirrors what many official portals and service providers require; several reputable providers even offer downloadable checklists so you can confirm what each state will ask for. Building from that model internally keeps our submittals clean and speeds up approvals. 

At Simplex we handle all temporary permits in one place (oversize, overheight, heavy haul, overlength, overwidth, plus fuel tax) so you do not have to chase separate forms or risk a last-minute rejection because one field was missing.

Route planning

Permit approval is only part of the equation; safe, lawful routing is the other. States use routing engines and engineering checks to keep heavy/over-dimensional traffic off sensitive infrastructure. In Texas, for example, TxPROS provides a Permit Wizard and generates compliant routes, factoring in clearances and bridge limits. Many customers can self-issue eligible permits through the system, which improves speed to issuance when the load falls within pre-screened thresholds.

Never rely on general familiarity with a corridor. Bridge postings, temporary work zones, and weather-related restrictions change. The Bridge Formula and posted load zones make axle spacing just as important as gross weight; a small reconfiguration can shift a load from “denied” to “approved.”

At Simplex we design the route that best balances miles, permit turnaround times, and safety. If a path is faster on paper but risks slow permitting or escort bottlenecks, we will propose a smarter alternative—before dispatch ever rolls.

Interstate permitting

While the FHWA provides the federal framework (and the Bridge Formula), permit authority and rules live at the state level, often with additional county/city layers. A solid interstate plan, therefore, is less about a “universal” rule and more about synchronizing state-by-state requirements on one timeline: what can be self-issued, what needs review, which corridors forbid night travel, and which segments demand escorts or law enforcement assistance. The FHWA maintains state contacts and references precisely so carriers can resolve these jurisdictional differences efficiently. 

At Simplex we determine the specific requirements for every state along your route, so you do not spend hours interpreting each DOT’s nuances or risk a roadside issue due to a county-level rule you missed.

Pilots, equipment, signage, and special rules

Pilot car requirements depend on width, length, height, and the route’s characteristics. Many states escalate requirements once you pass designated thresholds, and some corridors impose time-of-day or holiday restrictions for traffic flow. Expect signage (e.g., “Oversize Load”), flags, and lighting rules to accompany your permit, and prepare for stricter conditions on complex structures (e.g., tall loads crossing older bridges).

A disciplined approach is to treat pilots as a safety and schedule tool, not just a compliance necessity: the right pilot support prevents last-minute detours and expensive damage claims. When we scope a move, we confirm escort availability before committing to delivery windows; that single step reduces cancellations during peak construction seasons.

Costs, timelines, and common mistakes that derail operations

Costs vary by state, permit type, weight/size, and whether an engineering review is required. Timelines range from near-instant (self-issue) to several business days for complex moves or superheavy loads. Tools like TxPROS can meaningfully reduce issuance time for eligible permits by automating checks and enabling around-the-clock ordering—even though office phone support still follows business hours. 

The most common avoidable mistakes we encounter include:

• Submitting incomplete axle spacing or weight details
• Guessing at clearances instead of confirming measured height
• Ignoring holiday/curfew restrictions baked into permit terms
• Overlooking county/city permits where applicable
• Failing to align pilots with the permitted movement window

At Simplex we clear these obstacles in advance (validating your specs, aligning escorts with permit hours, and sequencing multi-state approvals)so your truck does not sit idle waiting for paperwork.

Do not forget UCR and fuel tax permits

OS/OW moves often expose gaps in Unified Carrier Registration (UCR) and fuel tax compliance. If your vehicle lacks an IFTA license/decals for the jurisdictions in scope, you may need temporary fuel permits to stay legal, and certain states maintain additional specialty permits (e.g., mileage-based). Leaving these to the last minute is a recipe for delays at the worst possible time.

Alongside the oversize paperwork, we flag any UCR or fuel-tax permits your trip will require, and we obtain them so you avoid unpleasant surprises at the scale house.

FAQs