When must you pull over to allow an ambulance or fire engine to pass?

When an ambulance or fire engine is using sirens and/or flashing lights, it indicates that they are responding to an emergency and require immediate passage. As a driver, the law enforces the responsibility to pull over and give way to these emergency vehicles to ensure they can reach their destination as quickly and safely as possible. This protocol not only aids the emergency services in performing their duties but also helps maintain public safety by preventing potential collisions.

The other options do not accurately reflect the legal requirements or best practices associated with emergency vehicles. For example, only pulling over during the day overlooks the fact that emergencies can occur at any time, requiring drivers to respond regardless of light conditions. Responding to a loud horn is not a standard or appropriate signal for yielding to emergency vehicles. Similarly, heavy traffic doesn't excuse a driver from the obligation to make space for emergency services; instead, drivers should find a way to safely pull over even in congested conditions.