When is it permissible to change lanes?

Changing lanes is permissible when it is safe to do so and the driver has signaled their intention. This approach ensures the safety of all road users. Signaling your intention to change lanes serves as a warning to other drivers about your planned movement, allowing them to adjust their speed or position accordingly. It's essential to check your mirrors and blind spots before making the maneuver to confirm that the lane change can be executed without endangering yourself or others.

Other options suggest scenarios that might not necessarily ensure safety or proper protocol. Heavy traffic does not automatically justify a lane change if it's not safe (as in option A). Feels necessary (in option C) can vary significantly from driver to driver and might not adhere to safe driving practices. Lastly, limiting lane changes strictly to overtaking (as stated in option D) does not account for instances where changing lanes might be necessary for reasons such as merging or preparing for a turn. Therefore, the safest and most responsible guideline is to change lanes only when it is safe to do so and to signal the intention clearly.