How many feet before a school bus comes to a designated stop will the warning lights flash?

When a school bus is preparing to make a designated stop, it is critical for the safety of children and other road users that other vehicles are warned in advance. The law mandates that the warning lights on a school bus will begin to flash at least 500 feet before the bus reaches the designated stop. This distance allows adequate time for drivers to react by slowing down or stopping, ensuring a safe environment for children getting on or off the bus.

The other distances mentioned do not meet the safety requirement necessary for alerting drivers in time to react appropriately. A shorter distance may not provide enough time for vehicles to safely adjust their speed and position, potentially leading to dangerous situations. Therefore, the correct answer is that the warning lights will flash 500 feet before the bus comes to a stop.