What action can reduce the risk of accidents when changing lanes?

Looking over one's shoulder and signaling before changing lanes is crucial for reducing the risk of accidents. This action allows the driver to check for any vehicles or obstacles that may be in the blind spot, which mirrors and rearview mirrors cannot cover effectively. By physically turning to look, the driver gains a more comprehensive awareness of surrounding traffic conditions.

Signaling the intention to change lanes is equally important, as it communicates the driver's actions to other road users, giving them time to react appropriately. This combination of checking blind spots and signaling creates a safer environment for both the driver and others on the road, helping to prevent collisions during the maneuver.

Speeding up before changing lanes can be risky, as it may reduce the time available to react to any unseen vehicles. Waiting until the last moment to decide is detrimental, as it often leads to hurried, impulsive decisions that increase the likelihood of errors. Finally, turning off all lights not only fails to assist the driver but can also confuse other road users, increasing the risk of accidents rather than reducing it.