Regulatory signs · MUTCD R3-4

What does the No U-Turn sign mean?

The No U-Turn sign (MUTCD R3-4) is a regulatory sign under the federal Manual on Uniform Traffic Control Devices, the national standard the states build from. Turning back on yourself is prohibited at this opening, so carry on and find a legal place to reverse direction.

Source: MUTCD 11th Edition, Chapter 2B, Table 2B-1, checked 2026-09-09.

No U-Turn symbol sign with a NO U TURN word plaque mounted below it on a metal post — A No U-Turn symbol sign in New Hampshire, with a separate NO U TURN word plaque mounted below it on the same post.Photo: MarkBuckawicki, CC0, via Wikimedia Commons.

What shape and color is the No U-Turn sign?

MUTCD code	R3-4
Group	Regulatory signs
Shape	Square
Color	White background, red circle and slash, black U-shaped arrow

What white means. Regulatory. A black legend on a white background is a law, not advice.

What red means. Stop, yield, or a prohibition. Red never advises, it always forbids or commands.

Regulatory signs. Every sign in this group has a statute behind it, so disobeying one is a citable offense on its own. Permit tests tend to word them as a duty you owe rather than show you the face.

Where is R3-4 supposed to stand, and where is it forbidden?

Section 2B.26 is a Standard: movement prohibition signs shall be installed where a specific movement is prohibited at an intersection approach, with two exceptions later in the section (paragraphs 13 and 17). Guidance says they should prohibit a turn from the whole approach, not assign a movement to one lane. For a No U-Turn, at least one should stand where a No Left Turn would: over the road, at the far left corner, on a median, or with the Stop or Yield sign on the near right corner.

At a signal, it should go next to a signal face that left-lane drivers look at, and an extra post-mounted sign may supplement an overhead one. If both the left turn and the U-turn are prohibited, paragraph 8 says to use the combination R3-18 instead of separate R3-2 and R3-4 signs.

Not on the approach to a roundabout

Paragraph 17 is a Standard. R3-4, R3-2, and R3-18 shall not be used on approaches to roundabouts to stop drivers turning left onto the circulatory roadway. The Support note says those signs can confuse drivers about which way they may go around the island. Direction around the circle is shown with a Roundabout Circulation plaque or One Way signs, not this symbol.

The turn you wanted is closed. What do you do?

At the opening that has the sign

1
Cancel the U-turn, not every left
This symbol prohibits turning back. A separate No Left Turn is what prohibits the left. If only R3-4 is posted, the left onto the cross street can still be legal.
2
If you do turn left, yield to oncoming traffic
The sign does not protect that left. In California, Vehicle Code section 21801(a) makes a driver turning left, or making a U-turn, yield to oncoming vehicles close enough to be a hazard. The diagram under this list is that left, not a U-turn.
3
Do not swing wide and finish as a U-turn
Starting in the left-turn position and then curling back onto the road you came from is the movement the sign prohibits. The arrow on the sign is the curl.
4
Go on to an opening that is actually open
The next legal place may be another intersection, or a median opening the authority has designated. A driveway on the left is not automatically that place.

Left turn still yields when only the U-turn is signed

The left-turning driver yields to oncoming traffic yields.

R3-4 removes the curl back to your own lanes. It does not give the remaining left turn a green arrow, and it does not make oncoming drivers wait.

Worked example

Elena Cho on a two-lane business street

1On August 4, 2026, Elena is westbound at 25 mph on a two-lane street in a California business district. She wants to head east. Mid-block, parked trucks cut her view to about 120 feet.
2Two statutes already close a mid-block U-turn here. Vehicle Code section 22102 allows a U-turn in a business district only at an intersection or at a divided-highway opening. Section 22105 also requires an unobstructed view of 200 feet in both directions, and she has 120.
3At the next intersection an R3-4 is posted at the far left corner, one of the spots Section 2B.26 names. She goes straight.
4Two blocks on, at an intersection with no signal, no R3-4, and a clear view well past 200 feet both ways, she yields to an oncoming car as section 21801(a) requires, then makes the U-turn.

Outcome. The sign closed one intersection. The statutes had already closed the mid-block turn. Neither told her that a left turn at the signed intersection was forbidden.

What still forbids the turn where no sign is posted?

A sign is not the only ban

Rule	What it adds beyond R3-4	Number in the statute
California business district	No U-turn except at an intersection, or at a divided-highway opening under 21651	VC 22102
California sight line	No U-turn without an unobstructed view for 200 feet both ways	VC 22105
Texas curve or hill	No turn to the opposite direction near a curve or crest if your vehicle cannot be seen within 500 feet	Transp. Code 545.102
Florida	No turn to the opposite direction unless it is safe, does not interfere, and no posted sign prohibits it	s. 316.1515
New York locations and sight line	No U-turn on a limited-access expressway, in a school zone or a New York City business district, or where other drivers cannot see you from 500 feet near a hilltop or curve	VTL 1161 (curve, crest, school zone); MV-21 Ch. 5 (expressway, NYC)

Florida makes a violation of 316.1515 a noncriminal traffic infraction, punishable as a moving violation under chapter 318. The section does not print a fine. New York Vehicle and Traffic Law 1160(e) says U-turns are made from and to the portion of the highway nearest the marked center line, and 1160(d) says that where signs require a different course, you turn only as those signs direct.

In New York, the No U-Turn face closes the reversal at this approach. The New York State Driver's Manual (MV-21), Chapter 5 also rules out a U-turn on a limited-access expressway, in a school zone, in a New York City business district, or at a hilltop, curve or other place where approaching drivers cannot see you from 500 feet. Passing this sign to seek another opening does not make the next U-turn legal; check that location and its sight line before turning.

No Left Turn

No Turns

One Way (arrow)

No Left Turn is a different arrow. No Turns closes both left and right. One Way is one of the signs Section 2B.26 names for showing direction at a roundabout, where R3-4 is barred.

Table 2B-1 gives movement prohibition signs, including R3-4, a 24 by 24 inch size on a single-lane conventional road, 36 by 36 on a multi-lane road and on an expressway, and 48 by 48 oversized. The freeway and minimum columns are blank for that row.

What is the No U-Turn sign often mistaken for?

No Left Turn (R3-2). The U-turn arrow doubles back on itself; the left-turn arrow does not.

The No U-Turn sign compared side by side with the No Left Turn sign
No U-Turnthis sign	No Left TurnR3-2
GroupRegulatory signs	GroupRegulatory signs
ShapeSquare	ShapeSquare
ColorWhite background, red circle and slash, black U-shaped arrow	ColorWhite background, red circle and slash, black arrow
What it meansTurning back on yourself is prohibited at this opening, so carry on and find a legal place to reverse direction.	What it meansA left turn out of this approach is prohibited, so the movement has to be made at another intersection.

Which signs get mistaken for the No U-Turn sign?

No Right TurnR3-1
No U-Turn (R3-4) and No Left Turn (R3-2). All three are the same square with a different black arrow inside the red circle, and the U-turn arrow curls back on itself.
No TurnsR3-3
No U-Turn (R3-4) and the Do Not Enter sign (R5-1), which bans entry rather than turning.

What does the permit test ask about the No U-Turn sign?

This question is from the practice bank, with the answer marked.

Question 1

A red circle with a diagonal slash over a symbol means:

A.A warning about the symbol
B.The action shown is prohibited(correct answer)
C.The action shown is required
D.Services related to the symbol

Why: Red with a slash always prohibits. The symbol tells you what is banned, such as a U-turn, a right turn or trucks.

Source: Federal MUTCD, 11th Edition (FHWA)

Questions drivers ask about the No U-Turn sign

If there is no sign, is a U-turn automatically legal?

No. Florida 316.1515 still requires the movement to be safe, to stay out of other traffic, and to be free of a posted prohibition. California 22102 bars a U-turn in a business district except at an intersection or a legal divided-highway opening, and 22105 requires 200 feet of unobstructed view both ways. Texas 545.102 bars the turn near a curve or crest when your vehicle cannot be seen within 500 feet. The sign is an added prohibition, not the only one.

Does a No Left Turn sign also ban the U-turn?

Section 2B.26 treats them as separate movements. It tells agencies that if both are prohibited, they should use the combination R3-18 rather than two separate signs. A lone No Left Turn is not the combination sign. Read the arrow that is actually posted before you assume both movements are closed.

Can this sign be posted on the way into a roundabout?

Not for the purpose of stopping a left turn onto the circulatory roadway. Paragraph 17 of Section 2B.26 forbids R3-4, R3-2, and R3-18 in that use. The manual says those signs can confuse drivers about which movements around the island are legal. Circulation is shown with a Roundabout Circulation plaque or One Way signs.

The plaque under the symbol says the words too. Is that a second rule?

No. Section 2A.09 describes educational word plaques that can accompany a symbol sign while drivers learn it, and a NO U TURN plaque restates the symbol. It does not add hours, a vehicle class, or a distance. Section 2B.26 shows those with supplementary legends on the sign itself, such as the vehicle-class and time-of-day versions R3-1b through R3-1h.

Sources

What are the other regulatory signs?

Yield Here To PedestriansR1-5

In-Street Pedestrian CrossingR1-6

Mandatory Movement Lane ControlR3-5

Optional Movement Lane ControlR3-6

Right (Left) Lane Must Turn Right (Left) sign

Right (Left) Lane Must Turn Right (Left)R3-7

Advance Intersection Lane ControlR3-8

Two-Way Left Turn OnlyR3-9b

Do Not PassR4-1

All 39 regulatory signs on one page, or every US road sign by shape and color.

Test yourself on this sign and the rest of the set with a road signs practice test for Florida, Texas, California or New York.

The artwork is the federal design itself, which the manual dedicates to the public domain in MUTCD 11th Edition, Part 1, Section 1D.06, checked 2026-09-09. The Interstate Shield, the 511 pictograph and the National Scenic Byway graphic are named exceptions and are not reproduced anywhere on this site.

Source: Manual on Uniform Traffic Control Devices, 11th Edition. Not affiliated with or endorsed by the Federal Highway Administration or any state agency.