Draft:Road signs in Ohio

Road signs in Ohio are regulated in the Ohio Manual of Uniform Traffic Control Devices (OMUTCD), the standard for traffic signs, road surface markings, and traffic signals in the U.S. state of Ohio. It is developed by the Ohio Department of Transportation "in substantial conformance to" the national Manual on Uniform Traffic Control Devices (MUTCD) developed by the Federal Highway Administration (FHWA).

Adoption and compliance
The first edition of the standard for traffic signs, road surface markings, and traffic signals in the U.S. state of Ohio was published in May 1924. The Ohio Manual of Uniform Traffic Control Devices was most recently updated on July 21, 2023. Ohio is among the ten states to have adopted its own MUTCD "in substantial conformance to" an edition of the national MUTCD, annotated throughout with state-specific modifications and clarifications.

The 11th edition of the MUTCD was released on December 19, 2023 with an effective date of January 18, 2024. Ohio has two years from the effective date to adopt the new OMUTCD, which will consist of the Federal MUTCD and a state-specific supplement with content specific to this state.

Regulatory signs
Regulatory signs give instructions to motorists, pedestrians, and cyclists. Signs including Stop, Yield, No Turns, No Trucks, No Parking, No Stopping, Minimum Speed, Right Turn Only, Do Not Enter, Weight Limit, and Speed Limit are considered regulatory signs. Some have special shapes, such as the octagon for the Stop sign and the crossbuck for railroad crossings. These signs are in the R series of signs in the MUTCD and typically in the R series in most state supplements or state MUTCDs.

R1 series: Stop and yield
The MUTCD's R1 series is for Stop and Yield. The 4-WAY and 3-WAY plaques (R1-3) were deprecated in the 2009 Edition of the MUTCD in favor of the ALL WAY plaque (R1-3P).

R2 series: Speed limit
The MUTCD's R2 series is for speed limit signs. Some state supplements and state MUTCDs place various speed limit signs in other series. Speed limits in the United States are always in miles per hour.

R3 series: Lane usage and turns
The MUTCD's R3 series of signs is for lane usage and turn signs.

For lane control signs (R3-H8b), the following letters and abbreviations are used to designate turns from lanes:
 * L: turn left only
 * R: turn right only
 * T: straight through only
 * LT: turn left and straight through
 * RT: turn right and straight through
 * LTR: turn left, straight through and right turn
 * UL: U-turn and turn left
 * LU: turn left and U-turn
 * X: lane divider