Why must drivers of tractor-trailers swing out to the left before making a right turn?

When drivers of tractor-trailers swing out to the left before making a right turn, it is essential to ensure they have enough space to make the turn safely. Due to the large size and length of tractor-trailers, turning requires a greater turning radius compared to smaller vehicles. By initially swinging left, the driver is able to align the truck properly and prevent the trailer from encroaching onto adjacent lanes or sidewalks, which is crucial for avoiding collisions with other vehicles or obstacles.

This maneuver helps to mitigate the risk of "off-tracking," where the rear wheels of the trailer do not follow the same path as the front wheels, potentially hitting curbs or other objects near the right turn. Therefore, it's vital for drivers of larger vehicles to plan their turns carefully, using the swing-out technique to make sure they can navigate turns without endangering themselves or others on the road.