Arch Rock Radar Speed Limit Sign and Speed Bump

Yosemite National Park » Arch Rock Radar Speed Limit Sign and Speed Bump » Document List

To reduce incidents of speeding at Arch Rock Entrance Station and increase safety for entrance station staff, the park is proposing to install a solar-powered flashing speed limit sign to provide a visual cue for drivers to slow down when the exit the park. In a study done by Texas A&M titled "EVALUATION OF DYNAMIC SPEED DISPLAY SIGNS" the authors found that speeds were reduced by as much as 9 mph with the use of flashing speed limit signs. The proposed sign would be collocated on an existing 20 mph sign, facing westbound. The sign post would be moved approximately 50 feet to the west towards the entrance station. The sign would only be operational during daylight hours so as not to impact wildlife at night. Installation of the sign would require soil disturbance to add a new 9 foot pole. The hole would be approximately 3-4' deep and 12" in diameter.

The park would also like to add a removable speed bump approximately 15 feet east of the stop sign in the westbound lane of the entrance station. Five holes would be drilled approximately 6 inches into the asphalt to install screws to anchor the speed bump. The removable speed bump would be in place during the peak season and removed in the winter to allow snow plows to easily come and go.