When turning left at an intersection, drivers must yield to which type of vehicles?

When turning left at an intersection, drivers must yield to oncoming vehicles that are going straight. This is crucial for ensuring safety at intersections, as oncoming traffic poses a significant risk during left turns. When you are making a left turn, you are crossing into the path of oncoming traffic, which may be approaching from the opposite direction. Therefore, yielding to those vehicles ensures that there is enough time and space for both vehicles to navigate the intersection without collision.

Other options like vehicles making U-turns, vehicles turning right, or bicycles in the bike lane can have varying rules and circumstances regarding whom they must yield to, but the most important and consistent rule is yielding to oncoming traffic, as this directly affects the flow and safety of traffic at intersections.