The 8 ft 6 in rule
Federal rules set a standard maximum vehicle width of 102 inches (8 ft 6 in) on the national highway network. A boat on a trailer that's wider than this is an oversize load and needs a permit from each state it travels through. Width is measured as the widest point of the loaded boat.
Escort vehicles
Escort (pilot car) rules vary by state. As a rough guide, many states require one escort once a load is wider than about 10–12 ft, and two escorts or a police escort for much wider loads. Some states also require escorts on certain roads or at certain heights or lengths. Transporters plan routes around these rules.
Height
There's no single federal height limit, but most states set limits of about 13 ft 6 in to 14 ft. Taller loads need permits and may need route surveys to avoid low bridges and power lines.
Travel restrictions
Oversize loads are commonly limited to daylight hours, may not travel on some holidays or weekends, and may be restricted in some urban areas at peak times. This can make a trip take longer.
How permits affect your quote
Permits, escorts and slower travel are all included in the transporter's price. That's why width has such a big effect on cost. Give the transporter accurate measurements so the quote covers the right permits.
Rules differ by state and change over time. Your transporter is responsible for obtaining the correct permits for your load.
Last reviewed 2026-11-15.