Final answer:
The suggested advanced warning sign spacing for rural areas is generally 500 feet. This spacing ensures that drivers have ample time to react, roughly equivalent to the length of about 20 car-lengths.
Step-by-step explanation:
The suggested advanced warning sign spacing for rural areas varies depending on the speed of the roadway and the specific conditions. However, for general purposes and as a part of traffic engineering standards, the minimum spacing typically recommended is 500 feet. This distance allows drivers enough time to recognize the warning sign and respond appropriately, whether by slowing down, stopping, or taking other necessary actions.
In rural areas where vehicles are often traveling at higher speeds, this spacing ensures there's ample time for reaction and increasing safety on the road. Additionally, the distance of 500 feet can be considered akin to the length of approximately 20 car-lengths, assuming an average car length of about 15 to 20 feet.