Keep your rig clear of low bridges
You see a low bridge ahead, and there's nowhere to turn the rig around. This helps you avoid that. Pick what you drive and set its height. The route then goes around roads your rig is too tall, too wide or too long for. It also avoids roads closed to trailers.
1Open Menu, then Route
Tap Menu, then the Route tab. Scroll down past Plan with AI to Vehicle for this route. Tap the button for your rig. Travel trailer is a truck pulling a travel trailer. RV is a motorhome or fifth wheel. Van is a van or truck camper. There's also Truck / 4x4. Your pick is for this route only. Use my usual rig puts it back.

2Check the size it plans for
A line under the buttons shows the size the app plans for. For an RV it says Planning for 13'1" tall · 40 ft long. Pulling something behind a Truck / 4x4, Van or RV? Tick Towing a trailer. This adds about 20 feet and the trailer's weight. It also plans you as tall as a travel trailer, 11'6", unless your vehicle is taller.

3Open Menu, then Account
Each rig starts with a standard height. We set it on the tall side to be safe. If your rig is a different height, you can set your own. Tap Menu, scroll to the bottom and tap Account. Find Your usual rig. This is the vehicle you normally travel in. Your own height is kept here.

4Set your own height
Under Your usual rig, tap your vehicle. This also makes it your default. Then tap change next to Height. Pick your height from the list. It goes from 5'0" to 14'0", in steps of 3 inches. It saves as soon as you pick, and you'll see (yours) beside it. That height is used for that vehicle on every route. To go back, pick Standard. Width, length and weight stay the standard for your vehicle.

5Plan Route, then read Warnings
Close Account. Add your start and end, and tap Plan Route. The route stays off roads with a posted height, width or length your rig won't fit. It also stays off roads closed to trailers. Then look under Warnings in the Route Summary. Any posted limit still on the route is listed there. It could be a low bridge, or a height bar at a campground gate. It's marked in red on the map too.

Good to know
The app only knows the limits that are in its map data. Plenty of real signs aren't there yet. So the signs on the road always come first. You can only set the height. Width, length and weight come from the vehicle you pick. The check for low bridges and height bars needs signal. With no signal, the app still keeps off the signed roads it has stored on your phone. A van or truck on its own gets warnings about posted limits. A travel trailer, an RV or anything towing also gets a route that goes around them.
Also in the app: maps that work with no signal, campgrounds and free sites, and Plan with AI. It plans routes for eight kinds of vehicle, from an enduro bike to a 40-foot RV.