You are driving down a two-lane road at 45 mph. What is the most likely occurrence if the oncoming vehicle's right wheels drop off the pavement?

When an oncoming vehicle's right wheels drop off the pavement, it often faces a loss of control. Drivers may instinctively steer back toward the roadway, which can lead to the vehicle swerving into the opposite lane. This reaction is influenced by the driver’s attempt to regain control and return to a stable driving position, especially at speeds like 45 mph.

In this scenario, the other options do not accurately describe the most likely behavior of a vehicle in this situation. While a vehicle could potentially continue on the shoulder, this typically requires good conditions and driver control, which aren’t guaranteed if the vehicle is dropping off the pavement. Spinning out and hitting a tree is also a possible outcome, but it's less common than simply swerving into another lane. Returning smoothly back onto the road is unlikely due to the bumpiness of the shoulder and potential loss of control. Thus, the tendency for the vehicle to veer into the lane of oncoming traffic is the most probable outcome.