Notwithstanding any law or regulation to the contrary, memorial signs for firefighters, EMS personnel, or law-enforcement officers killed along a Delaware road or highway in the line of duty are specifically authorized to be placed along the road near the place such person was killed. Such signage shall be constructed and installed in accordance with the Federal Manual on Uniform Traffic Control Devices, as published by the Federal Highway Administration under 23 C.F.R., Part 655, Subpart F.