How to Read a Land-Use Map: MVUMs, Route Numbers and Closures

Most off-road riders can read a topographic map well enough to find a lake. Far fewer can look at a Forest Service motor vehicle use map and say with confidence whether a particular road is open to their side-by-side in October. The two maps answer different questions. The topo tells you what the ground looks like. The land-use map tells you what you are allowed to do on it, and it is the one that a ranger will hold up if you are stopped. This piece explains the main types and how to read them.

On National Forest land the controlling document is the motor vehicle use map, usually shortened to MVUM. It is a legal document rather than a navigation aid, published by each forest and revised on its own schedule. If a route is not shown on the MVUM as open to your class of vehicle, it is closed to that class, whatever the ground looks like. The map uses distinct line styles for roads open to all vehicles, roads open to highway-legal vehicles only, and trails open to vehicles under a certain width. Read the legend before the map.

The width designations matter more than most riders expect. A trail marked for vehicles under a stated width admits a dirt bike or a narrow quad but not a full-size side-by-side, and a route marked for highway-legal vehicles only excludes a non-plated UTV even if it is physically easy. Your machine's width is in your owner's manual. Know it, because the difference between two trail categories on an MVUM is often the difference between a legal ride and a citation. Aftermarket wheels and wider tires can move a machine across that line.

Seasonal designations appear on the MVUM as a date range next to the route. A road shown as open only between two dates is closed outside them regardless of conditions, and many forests close routes for spring thaw or winter range protection. The dates are printed on the map in force, and the map in force is the one currently posted by the forest, not the one you downloaded two years ago. Confirm current dates with the managing agency before you go, because a route can close mid-season for fire, flood or wildlife reasons that the map cannot show.

Bureau of Land Management ground works differently. The BLM manages most of its off-road areas through a travel management plan and a set of designations: open, limited and closed. An open area, such as a designated dune field, allows cross-country travel within a boundary. A limited area restricts you to designated routes, which is the most common condition on desert two-track. A closed area is closed. Route numbers on BLM ground are typically posted on brown fibreglass markers at junctions, and the map and the marker should agree.

State and county ground adds a third layer. State forests, state parks and county recreation authorities publish their own maps, and the conventions vary. Some use the green, blue and black difficulty grading borrowed from ski areas. Some use numbered loops. Trail systems run by a regional authority often issue their own map with the permit and expect you to carry it. Where a state trail crosses federal ground, the federal designation still applies to that section, and the boundaries are marked on the map even when they are invisible on the ground.

Digital maps have made all this easier and slightly more dangerous. Mapping apps overlay MVUM data and BLM route data on a satellite image, which is genuinely useful. The danger is the update lag. An app that downloaded a forest's MVUM last year does not know about this year's revision, and the satellite image shows every user-created track as clearly as the legal route. A visible track is not an open route. Treat the app as a convenience and the agency's current published map as the authority.

A few habits make map reading reliable. Carry the map in force for the area, on paper or downloaded, and know the date on it. Match route numbers on the map to the markers at junctions rather than navigating by the shape of the track. Where a marker is missing or a junction does not match the map, assume the route is not open rather than assuming the map is out of date. Note the managing agency's office phone number, because a two-minute call from the trailhead resolves most questions before they become problems.

The reason to get this right is not only the citation. Riders who stay on designated routes are the main evidence a land manager has that motorised use is compatible with the land it manages, and every track outside the system is evidence for the other side. The map is the agreement between riders and the agency about where that use happens. Reading it carefully, and confirming it with the agency before you go, is the simplest way to keep the agreement in place for the next season.