On a high-speed urban roadway, how far apart should the advanced warning signs be?

The appropriate distance for placing advanced warning signs on a high-speed urban roadway is based on the need to provide adequate notice to drivers about upcoming conditions, such as work zones. A distance of 350 feet allows drivers sufficient time to react and adjust their speed while also taking into account other factors such as visibility, speed limits, and road geometry. This distance supports safe driving practices by giving motorists enough time to prepare for potential changes in road conditions ahead, ensuring they have time to notice, understand, and respond to the warnings presented by the signs.

Other distances, while they may seem appropriate, do not offer the same level of notice and reaction time as 350 feet does for high-speed urban environments. Proper placement of advanced warning signs is critical to accident prevention and helps maintain the flow of traffic despite the presence of work zones.