What is the recommended spacing for advanced warning signs on freeways and expressways?

The recommended spacing for advanced warning signs on freeways and expressways is based on guidelines aimed at ensuring drivers have adequate time and distance to respond safely to upcoming changes in road conditions or traffic situations. The correct choice specifies spacings of 1000', 1500', and 2640'. These distances are specifically designed to provide drivers with the right amount of notice depending on the type of sign and the speed of the traffic flow.

In higher-speed environments, such as freeways and expressways, having advanced warning signs placed at these intervals allows for the gradual deceleration of vehicles and ensures that drivers can react appropriately to upcoming hazards or information. Each distance offers incremental warnings that assist in preparing drivers for an upcoming condition, ultimately enhancing road safety and minimizing the risk of accidents.

Other spacing options provided do not align with the established guidelines for advanced warning signs, making them less effective in conveying necessary information to drivers in a timely manner.