How can a driver ensure there's enough space before changing lanes?

To ensure there's enough space before changing lanes, a driver should look in their mirrors and over their shoulder. This practice is essential because mirrors provide a view of vehicles in the adjacent lanes, but they have blind spots that can obscure the presence of other vehicles. By turning their head to look over their shoulder, drivers can gain a clearer, more comprehensive view of the area surrounding their vehicle, confirming that it is safe to shift lanes.

Assessing the speed of other cars, while helpful, does not directly inform a driver about the spatial availability in the next lane. Using turn signals is crucial for signaling intentions to other drivers but does not guarantee adequate space exists. Assuming there is always space can lead to dangerous driving situations, as it disregards the need for active observation and awareness of surroundings. Therefore, the most reliable method to determine if it is safe to change lanes is to check mirrors and perform a shoulder check to ensure the lane is clear.