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Heavy Haul Route Survey Guide

When state DOT permits require a physical route survey for an oversize move, what the permit officer is actually looking for, and the standard checklist of items dispatchers verify before submitting. Includes a printable checklist.

What a route survey is

A route survey is a physical or documented inspection of the proposed route for a permitted oversize/overweight move, verifying that the load can physically pass every constraint along the way. The deliverable is a survey package — typically photos, measurements, GPS coordinates, and a written assessment — submitted to the state DOT permit office for review.

For routine permitted moves (loads up to ~14' wide / 14'6" high / 120' long), the permit officer relies on the route's published clearance database and you don't need to physically survey. For superloads — anything that significantly exceeds those thresholds — a physical survey is usually required by permit conditions, and the route is approved (or rejected, or modified) based on what the survey finds.

When a survey is required

Triggers vary by state, but the common thresholds are:

Some states (e.g., Kentucky at 15'6"H, Tennessee at the discretion of the permit office for >17'H or >18'W) have explicit survey requirements at specific dimension thresholds. Others handle survey requirements case-by-case in the permit conditions. The per-state permit guide for each route is the authoritative source — see permit requirements by state.

What the survey covers

A complete survey package documents every constraint that could stop, damage, or force a reroute of the load. The categories:

Overhead clearances

• Bridges and overpasses. Posted clearance vs measured clearance (the two often differ). Measured at the lowest point of the structure, not the centerline.
• Sign gantries. Older sign structures on Interstate highways often lack posted clearances — measure each one.
• Traffic signals. Signal heights vary by jurisdiction; usually the binding constraint at metro intersections.
• Power lines. Federal minimum is 18' over highways but local lines may be lower. Coordinate with the utility for de-energization or temporary lift if the load exceeds line height.
• Railroad crossings. Catenary wires on electrified rail (Northeast Corridor, e.g.) are the lowest constraint and often need rail-side coordination for a controlled crossing.
• Tree canopy. Rural state routes with tree growth — easy to miss on a desk survey, easy to hit with a 16'+ load.

Lateral (width) clearances

• Bridge rails. Effective lane width between bridge rails on older bridges may be narrower than the posted lane width.
• Tunnel walls. Many state tunnels (Lincoln, Holland, Eisenhower) prohibit any oversize load — surveyed routes route around them.
• Construction zones. Active road work can reduce lane width temporarily. Survey within 30 days of the move.
• Narrow bridge approaches. Older state-route bridges may have stub guardrails or curbs that effectively narrow the usable width.

Turning and turning radius

• Intersection turns. A 150-foot combination cannot turn a normal city intersection — needs the inside or outside curb cut, possibly police-assisted traffic stoppage.
• Roundabouts. Modern roundabouts have splitter islands and mountable aprons; the survey documents whether the load can cross them.
• Highway exits and merges. Tight ramps (especially urban left exits) may require closing the ramp during the move.
• Driveways at origin and destination. Often overlooked. The load gets to the site and discovers the entrance is too tight.

Bridge weight ratings

• Posted bridge weight limits. Most state bridges are rated for HS-20 or H-20 loads. Anything over 80,000 lb gross may exceed the rating depending on axle configuration.
• Bridge engineering analysis. For loads requiring a state superload permit, the survey usually triggers an engineering review by the state bridge office. Calculation is per state procedure but the federal Bridge Formula B is the starting point.
• Posted detour routes. If a route bridge is below your load weight, the survey identifies the alternate route — usually a longer state highway or county road bypass.

Operational constraints

• Daylight movement windows. If the state requires daylight-only at your load's dimensions, the survey identifies stage points (truck stops, yards, secure parking) where the load can rest overnight.
• Holiday and weekend blackouts. The survey notes which days the route is closed to oversize traffic and confirms the move timing avoids them. See holiday movement restrictions by state.
• Rush-hour and metro restrictions. Many state DOTs restrict oversize on Interstates within metro areas during commuter hours. Survey identifies acceptable transit windows.
• School zones. Some local jurisdictions prohibit oversize moves near schools during start/end times. Easy to miss; expensive to violate.

How to conduct a survey

Step 1 — Build the proposed route

Start with a routing tool (PC*MILER, Google Maps Truck, or even Truck-specific GPS) and identify the most plausible route. Don't just trust auto-routing — heavy haul routes often follow state primary highways instead of Interstates because of clearances or weight restrictions. Cross-reference with the state DOT's published permit-route maps where available.

Step 2 — Desk-survey the obvious constraints

Before driving the route, pull up state DOT bridge databases, height-restriction maps, and permit-route GIS files. Identify every known constraint above your load dimensions. If 5+ constraints are flagged within the first 50 miles, consider an alternate route before driving.

Step 3 — Drive the route in a pilot car

Take a pilot car (passenger vehicle is fine; doesn't need to be the actual escort car for the move) and physically drive the route. Mount a height pole on the roof at the load's height plus 6 inches — this catches anything the desk survey missed. Drive in daylight; drive in the same direction the load will travel.

Step 4 — Photograph and measure everything questionable

At every bridge, sign, signal, tight turn, and narrow segment, stop and:

• Take photos from multiple angles, including a distance shot for context.
• Note GPS coordinates.
• Measure if the posted clearance is missing or suspect.
• Record any temporary construction or restrictions in effect.
• Identify the alternate route around the constraint if any.

Step 5 — Identify stage points

For multi-day moves, identify truck-stop or yard locations where the load can park overnight. Many oversize loads can't legally move at night or weekends; staging is required. The survey package should include a stage-point map with each location's address, lat/lon, and operating hours.

Step 6 — Submit the survey package to the permit officer

Compile the photos, measurements, route map, and written assessment into a single PDF package. Many state DOTs have a specific format; check the permit office's requirements. Most accept the package via email or upload through the state's permit portal.

Step 7 — Coordinate utility lifts if needed

For any utility line below the load height, contact the utility company directly. Lead times vary — 2 weeks for routine de-energization, longer for high-voltage transmission. The utility will quote a per-hour charge for the lift; this becomes part of your customer's bill.

Printable route survey checklist

Tip: surveys age. A route surveyed in summer may have different constraints in winter (snow narrows lanes; salt-related construction). For loads moving more than 60 days after the survey, re-verify any borderline constraints.

Cost and time

For a 500-mile multi-state route, expect:

• Desk survey: 2–4 hours, $200–$400 in dispatcher time.
• Physical drive-the-route survey: 1–2 days, $800–$2,500 in pilot car + driver hours.
• Photo + report compilation: 4–8 hours.
• Utility coordination (if needed): 2–6 weeks lead time; $500–$10,000+ in lift fees billed back to customer.
• Permit office review: 5–10 business days for the review and route approval after submission.

A complete survey for a superload move on a longer route can take 30–45 days from kickoff to approved permit in hand. Build this into customer quotes — the survey is part of the move, not free overhead.

Related guides

• Oversize / overweight permit requirements by state
• Bridge Formula B calculator
• Pilot car certification reciprocity
• Holiday movement restrictions by state
• Heavy haul glossary

Last updated: 2026-06-05. Survey checklist refined from real heavy-haul dispatcher practice. Spot something missing or out of order? Email [email protected] — we update within 48 hours.