picking lines on forest roads

Note:  this article is aimed at newcomers who haven’t driven on forest roads and are nervous about doing so.  They often wonder if 4x4 is necessary.   If you already drive off pavement you know this stuff.  These pics are from a forest road I hiked today and (and drove earlier this week in a front-wheel drive Promaster).  Nothing hard, but these are the pics I have at hand.

Each image will show a challenge then a proposed path through the challenge.  Depths are measured from the inchmarks transcribed on my walking stick from a tape measure.


  • look ahead at the immediate challenge and then the challenge beyond that.  Motorcyclists say “look where you want to go”

  • pick your line through the challenge, based on the physical dimensions and capabilities of your vehicle.

  • go slow enough for safety/control but maintain forward momentum.  Stopping dead in the middle of a pothole, rut, or mudhole can get you stuck.

  • pick smooth lines with minimal variation;   prefer to straddle or drive around rocks, ruts, etc.   Slamming into potholes isn’t good for you or for the van.

  • if you are not sure, get out and walk through the area first

  • trust your gut; if you are worried back out and make other plans

an easy example

To show what I’m talking about, here is a simple challenge.  Low (4”) gravel ridge between the tracks.  Apparent water erosion (9”) just beyond the left track.  Easy driving, but very low vehicles could get hung up if they dropped the left tires into the eroded area:

I’d scoot slightly to the right.  The red line on the pic is where I’d put the left tires.

We don’t care about the right tires because there is plenty of room on that side.  If we were in something narrow and low like a minivan we could put our left tires on the center ridge for a bit of additional clearance.   That’d put us close to the right edge, though.  Everything’s a tradeoff.

deep rut on center-right

The rut is 6-13” deep in various places.

I’d straddle it, placing the right tire to the right side of the rut.  There might be enough space for some vehicles to drive to the left of it.

serious pothole

15” deep hole in left tire track.

I’m thinking the left tire goes between the eroded area on the left edge and the pothole, straddling the low spot.  Narrow vehicles may be able to pass to the right.

snaking through

There are problems on both sides of the road, luckily not at the same time.  The ruts are up to 15” deep.  It’s also quite steep.

Maybe move to put the right tire in the best spot first, then slide to the left to straddle the big rut in the distance.

Or maybe straddle it the whole way from foreground to background.

pothole in left track

We are coming off a section with a 8” raised area between the  tracks.  Maybe we put our left tire on that high center ridge.  But now we have a 13” hole in the left tire track (just before it gets wet on the right side):

We could straddle the low spot by driving to the left as shown here.  Or maybe drive to the right of it, but that starts to put us in the wet spot ahead.

a bit of mud

This is actually a little tougher than it looks because this standing water comes from a nearby spring.  It’s constantly wet right here.

I’m thinking we put our left tire in that dry spot and straddle the mud as much as possible.  Our right side will get a little wet at first but it dries up after a bit:

This is a pretty normal forest road; 80% was easy driving with no particular attention needed.  Some, like the areas above, required a bit of attention.   I drove (and hiked)  about 2 miles on it and these were the only problem areas.