You are on a two-lane road and begin passing a vehicle. Midway through the pass, you see an oncoming car approaching. What should you do?

A PASSING EMERGENCY — when an oncoming vehicle appears before your pass is complete — requires rapid decision-making. THE SAFEST PRIMARY ACTION when the situation allows is to ABORT the pass: signal to the vehicle you are passing (flash your lights, signal right); brake to create space to slot back in behind them; return to your lane as quickly and safely as possible.

Why aborting is usually best: The oncoming vehicle is closing at the combined speed of both vehicles (e.g., 120 mph relative closing speed if both doing 60 mph); the sooner you create additional time/distance, the better.

When completing the pass is necessary: If you are too far into the pass to safely return (the vehicle you are passing has filled the gap you came from, or your speed and position make returning more dangerous than completing), then: accelerate firmly to complete the pass as quickly as possible; move as far right as practical once in front; the vehicle you've just passed should also reduce speed to create room; acknowledge the oncoming driver's reaction (they may flash lights or brake — keep your path).

The underlying lesson: Never begin passing unless you can SEE that the full passing maneuver is possible — that means enough clear sight distance ahead for the entire acceleration, full pass, and return. Many passing crashes happen because drivers began a pass they couldn't evaluate properly.