There are a few states that have specific regulations when it comes to the colors of brake lights. In some states, only red brake lights are allowed. However, in others, any color is allowed as long as it is visible from behind the vehicle. There are a few reasons for this regulation. First, red is the easiest color for other drivers to see. This means that they are more likely to notice when your brakes are engaged and will know to stop or slow down accordingly. Second, having all vehicles with brake lights of the same color makes it easier for drivers to identify which cars ahead of them have their brakes engaged. This can be helpful in avoiding rear-end collisions.