What action should you take if you encounter a vehicle stalled on your lane while driving downhill?

If you encounter a vehicle stalled in your lane while driving downhill, steering off the road if it's safe to do so is the most prudent action. This approach allows you to avoid a collision with the stalled vehicle while maintaining control of your own vehicle. Moving off the road can create a clear path for you and other vehicles, reducing the risk of an accident and ensuring that your vehicle does not get trapped or cause an obstruction in a downhill situation, which can be particularly dangerous due to the momentum and speed that can build up downhill.

The other options, while possibly seeming viable in certain contexts, can lead to increased danger. Speeding up to pass can compromise control of your vehicle and may not provide enough time or distance to safely maneuver around the obstacle, especially on a downhill grade. Looking for an alternate route could be impractical if there are no safe routes nearby, and it may result in unnecessary confusion or delay during your descent. Braking hard to a stop can cause skidding or loss of control, especially on downhill slopes where brakes may overheat or fail if applied abruptly. Thus, steering off the road is a safe and often effective method of navigating such situations.