The bridge on Black's Mill Road will be closed Thursday as crews make some upgrades to the crossing.
Dawson County Public Works Director David Headley said new guardrails will be installed "to improve the safety and keep the traffic controlled within the bridge templet."
New safety caution signs have also been placed on the roadway leading to the bridge.
The crossing will reopen immediately after the railings are installed.
Originally constructed in the early 1950s, Black's Mill Bridge is a single-lane wooden crossing deemed functionally obsolete by state transportation officials.
Commissioners earlier this month opted to add caution signs and new guardrails to the aging structure after residents said closing the crossing would cause hardship and present safety issues.
The bridge, according to Headley, is structurally safe for cars and trucks weighing less than 5 tons, but should be considered dangerous for heavier vehicles like buses and fire engines.
The cost to completely replace the single lane structure with a two lane paved road and 26-foot span arch culvert, which would significantly improve its DOT rating, could run as high as $325,000, according to Headley.
The upgrade could be considered for a future 1-cent tax project, commissioners have said.