King tide across the Nippon Causeway
It is 20:40 and you are driving a borrowed five-seat pickup from Bikenibeu toward Betio. Between the islets the road narrows to a single lane in each direction with no shoulder and no street lighting. A king tide is running; seawater has crossed the ocean-side ridge and is flowing across the road for about 70 metres. In your headlights the water looks 10–15 cm deep near the centre but darker and faster at the lagoon-side edge. A loaded minibus is coming the other way, throwing spray, and its driver flashes headlights. Behind you a motorcycle is following closely. Your passenger says the causeway was dry an hour ago. The pickup sits low, with its air intake behind the front bumper, and the engine has been running slightly rough since the last refuel.
1. What factors should decide whether you drive through the flooded section, and what is the safest immediate action?
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Stop well before the water, on the highest dry section, with hazard lights on. Do not enter just because the minibus did: its tyre size, intake height and line are different, and the driver may be guessing. Judge three things from outside the vehicle: depth (use a stick, kerb or known marker), speed and direction of flow (look at debris; if the water is moving faster than a walk, a low pickup can be pushed or float), and the exit line on the far side. Ten to fifteen centimetres of still water may be passable at walking pace in a low gear, but 15 cm of moving salt water is not a safe bet at night with an unknown lagoon-side edge. Your rough-running engine and low intake add risk. The safest action is to wait for the tide to fall or turn around and postpone the trip. If you must cross after checking, let the oncoming vehicle finish, leave a gap, use first gear, keep steady revs and do not change gear mid-water.
2. If you enter and the engine cuts out halfway across, what should you do?
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If the engine dies in the water, do not keep cranking it. Water can enter the intake and exhaust, and restarting can hydraulic-lock the engine or damage the electrical system; salt water makes that worse. Switch off the ignition, leave the lights on if they still work, and get everyone out on the upstream side, away from the deeper lagoon edge. Do not open a door into fast-flowing water if that will flood the cabin faster; use the window or the side away from the current. Move to the highest dry ground and call for help. Do not stand in the water to push. Once out, treat the vehicle as disabled and warn the motorcycle and any other traffic with a torch or hazard lights. Report the location.
3. How should the motorcycle following closely change your plan?
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It removes any option of a sudden stop in the water or a sharp swerve. Signal early and brake progressively so the rider has time to react; if you decide not to cross, stop on dry ground with hazard lights on and leave enough space for the motorcycle to pass on your right if it chooses. Do not wave it through the flood. If you do cross, the rider may follow your line, so your choices affect two vehicles. Keep a steady, slow speed, avoid throwing a bow wave, and do not reverse unexpectedly. If the motorcycle tries to overtake into the water, hold your line and let it go rather than blocking it.