When can you legally drive in a designated bicycle lane?

You can legally drive in a designated bicycle lane when you are turning or merging, provided that you yield to cyclists who may be using that lane. This rule is in place to ensure the safety of cyclists and to maintain the flow of traffic. When a vehicle needs to make a turn at an intersection or merge into a roadway, it may require the driver to cross into the bicycle lane. However, it is crucial for drivers to check for cyclists and allow them right of way in the lane before proceeding, as cyclists have the same rights to the road as motor vehicles.

The other options do not align with traffic laws regarding bicycle lanes. Driving under 25 mph does not grant permission to use the lane. Being in the lane when it is empty does not justify it either, since the law emphasizes safety and respect for cyclists regardless of the presence of other road users. Lastly, stating that you cannot drive in a designated bicycle lane under any circumstances does not account for the lawful scenarios where merging and turning are allowed, provided that proper yielding practices are followed.