Warning signs should be posted no less than _____ feet above the road elevation.

The correct answer is that warning signs should be posted no less than 7 feet above the road elevation. This height requirement is established to ensure that the signs are clearly visible to drivers, particularly large vehicles such as trucks and buses that may have higher clearance needs.

By positioning warning signs at this height, it minimizes the risk of them being obscured by roadside vegetation, debris, or other obstacles. Additionally, this standard helps maintain visibility at night and in adverse weather conditions, contributing to overall traffic safety in work zones.

The height of 7 feet is consistent with guidelines provided by standards like the Manual on Uniform Traffic Control Devices (MUTCD), which is vital for effective communication of risks and instructions to road users. Being compliant with this regulation is necessary to enhance the safety of both workers and motorists in construction or maintenance areas.