How can a driver legally change lanes in Illinois?

A driver can legally change lanes in Illinois by signaling and checking mirrors before proceeding. This practice is essential for ensuring the safety of all road users. Signaling alerts other drivers of your intention to change lanes, allowing them to react appropriately. Checking mirrors ensures that the lane you intend to move into is clear of other vehicles and obstacles. This two-step approach promotes safe driving conditions and reduces the risk of accidents.

The other options do not align with safe or legal lane change practices. Changing lanes at any time without signaling disregards the need to inform other drivers, potentially leading to dangerous situations. Using the horn to alert other drivers is not a standard practice for changing lanes; horns are typically used for warning or as a form of communication, not as a signal for lane changes. Waiting for traffic to clear completely can be impractical in many situations, as road conditions may require drivers to change lanes even when traffic is present, provided it is done safely and with proper signaling.