Wrong Way Sign: R5-1a Sizes, Placement and Ramp Rules
Updated · By the Cone to Curb editors
The wrong way sign is the MUTCD's R5-1a: white WRONG WAY lettering on a red horizontal rectangle, used with the round DO NOT ENTER sign to stop drivers going against traffic. The standard size is 36 x 24 inches on single-lane roads and 42 x 30 on multi-lane roads and freeways, and on freeway exit ramps at least one is required.
| Road | WRONG WAY (R5-1a) | DO NOT ENTER (R5-1) |
|---|---|---|
| Conventional road, single lane | 36 x 24 | 30 x 30 |
| Conventional road, multi-lane | 42 x 30 | 36 x 36 |
| Expressway | 36 x 24 | 36 x 36 |
| Freeway | 42 x 30 | 48 x 48 |
| Minimum | 30 x 18 | (none) |
| Oversized | 42 x 30 | 36 x 36 |
Sizes in inches, from MUTCD Table 2B-1.
Wrong Way supplements, it doesn't replace
Section 2B.47 lists the R5-1a as a supplement to the DO NOT ENTER sign where a road meets a one-way roadway in a way that doesn't physically stop wrong-way entry. The pair works in sequence:
- DO NOT ENTER faces the driver at the point of entry.
- WRONG WAY stands farther along the one-way road, on the same side, so a driver who got past the first sign gets a second, louder message.
Exit ramps: three required signs
Where an exit ramp meets a crossroad in a way that invites wrong-way entry, Section 2B.48 requires:
- at least one ONE WAY sign for each direction on the crossroad where the ramp meets it,
- at least one DO NOT ENTER sign near the end of the ramp, facing a driver who might turn onto it,
- at least one WRONG WAY sign on the ramp, facing a driver already going the wrong way.
The section also allows a lower mounting height on freeway and expressway exit ramps: where an engineering study supports it and there are no parked cars, pedestrians, snow or plants in the way, DO NOT ENTER and WRONG WAY signs along the ramp may sit as low as 3 feet above the pavement, in the headlight beams of a wrong-way driver.
Making them easier to see
- LEDs. Red LEDs in the sign border, either on all the time or switched on by a detector, are allowed under the MUTCD's LED provisions (Section 2A.12) and are common on ramps with a wrong-way crash history.
- Pairs. Signs on both sides of a wide ramp or one-way street.
- Red pavement markers. Raised markers that show red to a wrong-way driver, along the ramp lane lines.
In parking garages and lots
Parking areas aren't covered by the MUTCD (Section 1B.01), but one-way garage ramps and drive aisles use the same signs because drivers know them. A WRONG WAY sign at the top of a garage exit ramp, at headlight height, stops a lot of mistakes.
Mistakes we see
- WRONG WAY without DO NOT ENTER. It's the second sign, not the only one.
- Both signs on one post at the entry. The WRONG WAY goes farther along.
- Small 30 x 18 signs on a multi-lane road. Use 42 x 30.
What it costs
Ballpark U.S. prices in late 2026: $50 to $120 for a 36 x 24 R5-1a with high-intensity sheeting, $80 to $180 for 42 x 30, and $1,000 or more for a solar LED-bordered sign.
Where to buy
Sign shops and traffic safety distributors; LED signs from flashing-sign makers. Ask for the code, size, sheeting type, and for LED signs the power source and flash pattern.