Is a superload permit different from oversize?
Yes. A superload is a heavier or larger tier than ordinary oversize/overweight — typically over 16 feet wide, 100 feet long, or 200,000 lbs combined. Each state's threshold differs. Superloads require route engineering, bridge analysis, and often escort planning before the permit issues.
Oversize covers any load exceeding the state's standard legal limits — usually 8'6" wide, 13'6" tall, 53' long, or 80,000 lbs gross. Most states issue oversize permits same-day for $20-$60 and require flags / banners / chase vehicle.
Superload is a separate tier with no single national threshold — every state defines it differently. Common state thresholds: width over 14-16', length over 100-110', height over 14-16', or combined gross over 200,000 lbs.
Superload permits require route engineering: a state engineer reviews the proposed route for bridge clearance, pavement load capacity, and traffic-control needs. Engineering review takes 1-4 weeks. Some routes get rejected and require alternate paths.
Multi-state superloads are the hardest case — each state engineering review runs in sequence, and the route in one state has to feed into the next. Carriers running superloads typically pre-plan 4-8 weeks out and use a permit consultant or filing service that has direct working relationships with state engineers.