TERRAIN ASSESSMENT: THE WALK BEFORE THE DRIVE

The Technique

1. Stop early, and stop somewhere useful. The decision starts before you get out. Pull up far enough back that you still have room to turn around on ground you have already proven, which on a narrow track means stopping at the last widening rather than at the lip. Kill the engine. A running diesel and a queue of vehicles idling behind you is pressure you do not need while you are thinking, and pressure is what makes people commit to lines they would otherwise reject. If you are leading, put the stop on the radio before you open the door, so nobody creeps forward and quietly removes your reverse option.
2. Walk the whole obstacle, including the parts you do not intend to drive. Walk the bypass first, so you know what your fallback actually is rather than what you assume it is. Then walk both plausible lines through the obstacle itself, then keep walking well past the exit. The exit is where expeditions get stopped, and the second obstacle is often thirty metres beyond the first, out of sight from the bonnet, on ground you will arrive at with no momentum and no room. Walking it means walking it, not standing on the bank and pointing.
3. Read the ground with your feet and a stick. Push a heel in hard where each tyre will land and feel for the change from firm to soft, because the transition is where you break through. Cut a stick and probe the soft spots, the ruts, the water, and the base of any bank you plan to climb. What you are after is bottom composition and depth of the soft layer: a hundred millimetres of slop over rock drives, the same slop over bottomless silt does not. Wet clay that takes a clean boot print will polish to glass under one spinning tyre.
4. Read the record other people left. Tyre tracks tell you what has been through and roughly when, read against the last rain. Spoil thrown high up the far bank means somebody carried speed, and you can see whether it worked. Long parallel gouges in the crown of a rut mean vehicles have been dragging their belly there. Bark scarring and chewed roots on a tree at bumper height mean people have needed a winch at that exact spot, more than once. Fresh oil, coolant or shattered plastic is a failure report. A bypass more used than the main line is the collective verdict of everyone before you, already published.
5. Check geometry against your actual vehicle, not the brochure. Approach, departure and ramp-over angles all change once you fit a rear bar and wheel carrier, hang a towbar off the back, load two hundred kilograms in the rear and settle the springs. Know your true lowest and most fragile points by having crawled under the thing: the rear diff pumpkin offset to one side, the exhaust flange, the long-range tank, the sidesteps that are not sliders, the plastic bumper valance that is going to fold into a wheel. To judge a crest, stand at it and note where it meets your body, then walk back and compare that height against known points on your vehicle. Hold a straight stick along the chassis line to project the belly path over a mound.
6. Name the failure mode out loud. The useful question is not "will I make it" but "how does this specific piece of ground break me". High-centre on the crown between ruts. Cross-slope roll once the uphill tyre unloads. Nose dive at the exit and a bar strike into the far bank. Bank collapse under the downhill wheels after four vehicles have already softened it. Water over the bonnet. Sidewall cut on a rock edge you can see from here. Stall on the lip and a roll back into the hole. Once you have named it, the mitigation gets specific: a different line, a spotter on that corner, boards under one wheel, or a winch line on before you move.
7. Plan the recovery before the attempt, not after it. Say out loud where the recovery vehicle stands, on what ground, on which side, and what it anchors to. Check that the anchor exists before you need it, because a plan that depends on a tree that turns out to be a dead stringybark with a rotten root plate is not a plan. Ask which direction you would pull: back the way you came is usually right, and usually means the recovery vehicle should not have followed you in. If the honest answer is that you would have to winch uphill and backwards through the hole you just made, you have your answer about whether to attempt it at all.
8. Build it down, or refuse it. The fastest recovery is the one you engineer away twenty minutes earlier with a shovel. Fill the hole, knock the lip off the exit, lay rocks or timber under the wheel that is going to drop, cut a ramp into the bank, place boards before the attempt rather than after. Groups routinely spend an hour on a recovery they could have prevented with ten minutes of work. Then keep the refusal available. Set your turnaround criteria before you are standing at the obstacle with an audience, and hold to them. Four hundred kilometres from a road, a broken vehicle is not a bad afternoon, it is the end of the trip for everyone in the convoy.

Common Mistakes

Walking only the line you already decided to drive. Fix: walk the bypass and the second-choice line first, before you have any pride invested in one of them.

• Assessing the entry and ignoring the exit. Fix: make it a rule that you walk to the far side and back before you form any opinion, every single time.
• Trusting a track note, a guidebook or a video as current. Fix: treat all of it as history. One wet season, one grader or one bogged tour bus changes an obstacle completely.
• Letting the convoy's momentum make the decision for you. Fix: the person who walks it makes the call, and the call is announced before opinions are invited.
• Judging depth from the bank. Fix: water and shadow both flatten. Nothing counts until something has been physically pushed into it.

The Drill

On your next trip, pick three obstacles you would normally have driven straight into without stopping, and stop anyway. Before you move, write down or voice-record four things: the line, the named failure mode, the mitigation, and the recovery plan including the anchor. Then drive it. Score yourself afterwards on whether the vehicle behaved the way you predicted. Three out of three is the standard. If you are getting one or two, your reading is behind your driving, which is the condition that eventually costs someone a chassis.

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