What it does
Fort Route checks the elevation profile of the route you plan and picks out the sustained grades: 5% or steeper for at least a mile, or 6.5% or steeper for at least half a mile. Shorter or gentler pitches are left out, so the stretches it shows are the ones worth planning around.
For every downgrade on the route, you hear a spoken warning 2 miles before it starts, with the grade and how far it runs. That is enough notice to settle your speed and pick a gear before the top, instead of sorting it out on the way down.
How it works in the app
- Plan your trip as usual. Fort Route reads the elevation along the route you pick.
- Look for the steep-grades card on the route sheet. It lists the sustained grades on that route.
- Open the list to see each stretch highlighted on the map, so you know exactly where each one sits on the trip.
- Start turn-by-turn navigation. Two miles before each downgrade, Fort Route speaks a warning like this one: "Steep downgrade in 2 miles: 6 percent for 4.9 miles. Gear down before the top."
Because the check runs when you plan, you see the grades before you leave, not only when the warning plays. On a trip through mountains you rarely run, the list is a quick way to see how many long grades are ahead and where they fall between your stops.
The card works with the rest of your plan. Your truck-safe route already accounts for height, weight and hazmat, and the grade list adds the terrain on top of it.
Posted signs win
The grades come from elevation data along the route line, not from the signs at the top of the hill. Elevation data smooths the terrain, so the percentage and length Fort Route gives are estimates. A grade can start a little before or after the point where the app places it.
When a posted sign gives a different grade or length, follow the sign. The app's number is there to get you ready, and the sign is the authority on that road.
The thresholds also leave some long hills off the list. A 4% grade that runs for 8 miles is below the 5% line, so it gets no warning, even though it can still call for a lower gear with a heavy load. Treat every warning as a heads-up, and keep reading the signs on grades the app doesn't mention.
For descent technique and brake checks, read the guide to mountain driving and steep grades.
Frequently asked questions
Which grades does Fort Route warn about?
Fort Route flags grades of 5% or more that last at least a mile, and grades of 6.5% or more that last at least half a mile. Anything shorter or gentler is left off the list. The spoken warning plays for downgrades.
How early does the spoken warning come?
The warning plays 2 miles before the downgrade starts. It gives the grade and the length, for example "6 percent for 4.9 miles", and reminds you to gear down before the top.
Will the app's grade match the posted sign?
It can differ, because Fort Route calculates grades from elevation data instead of reading the signs. Small differences in the percentage or the length are normal. When they disagree, the posted sign is the one to follow.
Do I need to be navigating to see steep grades?
No, the steep-grades card and list are available on any planned route. The spoken warning 2 miles before a downgrade plays only during turn-by-turn navigation, with Fort Route open on your phone.