What's so bad about U-turns?

[LC Strawhouse]

Any insight on why "the Man" makes such a big deal about U-turns while driving? I'd think they're a perfectly legitimate and occasionally necessary maneuver.

I'm talking about city or suburban driving (not highways of course). "No U-turn" signs are common as flies, including at the exact places where it would be most convenient, and it's very much enforced by the police. I don't get why it's dangerous or something - one would use the same kind of judgment as when making a standard left turn.

Is it that much better to make a left turn into a residential area, and then double back after backing in & out of a random person's driveway?

[Mr Downtown]

Well, in general U turns are perfectly fine. It's only a problem at the few places where regulatory signs have been erected. That said, some cities (such as Chicago) have citywide bans.

And there are states (Michigan) where they are actually part of the highway geometrics and expected behavior.

[TimeWinder]

Because it's an uncommon maneuver. Most people don't have a good sense of the turning radius of their car -- and most guess low. U-Turns are hard on curbs, fire hydrants, lawns, and cars themselves. Even worse, it takes longer than you guess, especially if you misjudge the turning radius and have to back up to correct -- and now you're in reverse and panicking because of a misjudgement, and you've got two lanes of traffic to worry about, the one you're in, and the one you came from, which your vehicle may accidentally reverse into.

I live in a city basically designed around U-turns: hard center medians on avenues, with designated U-turn locations to get to locations on the other side. The U-turn locations all have an extra lane of space (looks a little like a bus-pullout) on the receiving lane, and even then there are lots of tire-marks on the curb.

[runner pat]

U-turns slow the car far more than a left turn,increasing the exposure of the turning car to oncoming traffic.
Also, oncoming traffic can't always know which lane the turning car will end in.

[Zsofia]

Because people aren't expecting for you to do it, particularly in the places where you think you should and in fact you should not. I almost got slammed into by a woman who gave me the finger when I was turning right on an arrow right when she decided to whip in to a U-turn on that same street last week.

[Implicit]

Originally Posted by TimeWinder

Because it's an uncommon maneuver. Most people don't have a good sense of the turning radius of their car -- and most guess low. U-Turns are hard on curbs, fire hydrants, lawns, and cars themselves. Even worse, it takes longer than you guess, especially if you misjudge the turning radius and have to back up to correct -- and now you're in reverse and panicking because of a misjudgement, and you've got two lanes of traffic to worry about, the one you're in, and the one you came from, which your vehicle may accidentally reverse into.

Yup. How often do you see people who can't even maneuver a 90 degree turn into a parking spot in a parking lot and have to reverse at least once to pull into the spot? Same problem occurs with U-turns, people don't do U-turns very often and have no concept of how much space they need to make a 180 degree turn.

[Amblydoper]

I think it all comes down to stupid drivers.

TimeWinder has it right. Its an uncommon maneuver.

Many intersections give right turn green arrows along with left turn green arrows. If a left-turner decides to make a u-turn, he crosses into the path of a right-turner, possibly causing an accident. In a perfect world, the u-turner would know that he is giving up his right-of-way, and must yield, but that doesn't happen often. Its easier for the city to post a no-u-turns sign at that intersection.

Its a lot like those annoying left-turn-red-arrows at some intersections. Their purpose is to prevent left turns where road/visibility conditions make it difficult to properly gauge breaks in traffic. But those lights are used in many intersections where there is no legitimate reason to prevent a turn, other then to keep stupid drivers from causing accidents.

Traffic engineers seem to design roads for the stupidest drivers. Its an inconvenience, and it certainly dumbs-down the task of driving, but it probably saves lives and money

[Mr. Krebbs]

Originally Posted by Amblydoper

Traffic engineers seem to design roads for the stupidest drivers. Its an inconvenience, and it certainly dumbs-down the task of driving, but it probably saves lives and money

Or maybe it just inconveniences us, without making anything more safe or more efficient.(Warning: PDF)

[Cat Whisperer]

My take is that it's unpredictable and dangerous due to crossing pretty much all the lanes of traffic.

[Sailboat]

Originally Posted by Mr. Krebbs

Or maybe it just inconveniences us, without making anything more safe or more efficient.(Warning: PDF)

Ok, I opened that .pdf, read the first couple of pages, read the conclusions, skipped to the end, briefly eyeballed some diagrams...and I have no idea what you're getting at. What I read in that study neither indicates that traffic engineers inconvenienced anyone nor any conclusion at all about U-turns.

It's possible that I missed some subtle point. However, it would help if you could explicate what you meant by posting that link, what you saw in it and why you concluded it's relevant.

It's not that helpful to post an assignment for readers to have to plow through and assess.

[FasterThanMeerkats]

Originally Posted by Mr. Krebbs

Or maybe it just inconveniences us, without making anything more safe or more efficient.(Warning: PDF)

Agreeing with Sailboat, the PDF seems in direct contradiction to the title on the hyperlink. It's talking about taking an existing roundabout and changing the traffic pattern. Page 7/56, general conclusions actually states (bolding mine):

"Traffic safety in terms of accidents seem to have improved to date since the removal of traffic signals. However, it should be noted that full accident data for the three years since reconstruction was not available. Further comparisons and analysis of longer periods will provide more definite conclusions about traffic safety at the Laweiplein."

That doesn't mean the old pattern wasn't safe, just that the new one appears safer. And no U-turns were mentioned.

[Giles]

Mr. Krebbs' PDF was about replacing traffic lights with a roundabout and finding that the roundabout was better (a conclusion which does not surprise me). Except that roundabouts make it very easy to do U-turns, while traffic lights generally make it impossible, I don't see the relevance either.

[Baracus]

Originally Posted by Zsofia

Because people aren't expecting for you to do it, particularly in the places where you think you should and in fact you should not. I almost got slammed into by a woman who gave me the finger when I was turning right on an arrow right when she decided to whip in to a U-turn on that same street last week.

I run into the same problem but I am the U-turner and the cross traffic has a stop sign. Even though just about every other car in the turn lane is making a U-turn, the people from the cross street making a right never seem to account for that possibility.

[septimus]

In the big city near where I live in Thailand, there are two right-turn lanes at some major intersections (think mirror-image left-turn as we drive on left), but it's not at all unusual for someone in the middle lane to make a U-turn! (Keep alert when you're driving in rural Thailand.)

[Wheelz]

Originally Posted by Amblydoper

Many intersections give right turn green arrows along with left turn green arrows. If a left-turner decides to make a u-turn, he crosses into the path of a right-turner, possibly causing an accident. In a perfect world, the u-turner would know that he is giving up his right-of-way, and must yield, but that doesn't happen often. Its easier for the city to post a no-u-turns sign at that intersection.

This.
Near my house, there's a busy gas station on the southwest corner of an intersection. Because of the medians, northbound drivers who want to get there need to either turn left at the intersection and go around the block (and in fact there are signs posted saying to do exactly this) or make an illegal U-turn ("No U-turn" sign posted as well). Meanwhile, eastbound traffic has a right-turn green arrow at the same time as northbound has the left arrow. Almost every day I see some chucklehead going for the U-ey and nearly slamming into someone making a legal right turn.

Baracus, granted, everybody should be careful. But it's shouldn't be the onus of a driver with the right-of-way and executing a perfectly legal maneuver to "account for the possibility" of someone else doing something dangerous and illegal.

[control-z]

U-Turns are a bad idea when there is much traffic. But I would agree that there are many situations where they would be perfectly fine with little or no nearby traffic. Unfortunately signs can't take that into account (yet?)

[brad_d]

Originally Posted by Amblydoper

Many intersections give right turn green arrows along with left turn green arrows.

If U-turns are legal for the left-turners, then this is horrible design! I've never seen an intersection set up this way, and hope I never do....

[Tastes of Chocolate]

I've got a 2003 Saturn coupe, and that car can't turn tight enough to make a U turn from a stop, even if I have 2 lanes on my left to turn into. I would end up nose into a curb, have to back up, and go forward again. In the mean time, I've now blocked the left turn lane, the on coming traffic, and quite possibly the cross traffic, if the light is short.

[BwanaBob]

Originally Posted by Zsofia

Because people aren't expecting for you to do it, particularly in the places where you think you should and in fact you should not. I almost got slammed into by a woman who gave me the finger when I was turning right on an arrow right when she decided to whip in to a U-turn on that same street last week.

Winner. Any move by you that requires me to give up my right of way, or deviate from it, is by definition dangerous and probably assholish too. Like making a right on red in front of me when I have the green, because you think you can beat me - you force me to slow down to prevent hitting you. Ditto the U-turn.

[Frank]

Originally Posted by Amblydoper

Its a lot like those annoying left-turn-red-arrows at some intersections. Their purpose is to prevent left turns where road/visibility conditions make it difficult to properly gauge breaks in traffic. But those lights are used in many intersections where there is no legitimate reason to prevent a turn, other then to keep stupid drivers from causing accidents.

I'm not sure if it's Missouri law or St. Louis County law, but here intersections have left-turn arrows that are always green or red if there are three (or more) thru lanes coming the other way. It's not as much help as you might think. Even two lane streets have left-turn arrows that may be red, green, flashing yellow, or off completely. There are also frequently intersections with the green left-turn arrow before the full green from one direction, and after it from the other. With no signs stating that oncoming traffic may have an extended green!

I can't begin to count the number of people I've seen hung out to dry because they expected to complete their turn after oncoming traffic stopped. There's no consistency. You have to memorize the light patterns of each intersection.

[LC Strawhouse]

Originally Posted by BwanaBob

Winner. Any move by you that requires me to give up my right of way, or deviate from it, is by definition dangerous and probably assholish too. Like making a right on red in front of me when I have the green, because you think you can beat me - you force me to slow down to prevent hitting you. Ditto the U-turn.

But doesn't this complaint also apply to a standard left turn made against traffic? A U-turn is just an extended left turn, really.

Neither U-turns or left turns or right turns on red (or changing lanes) require any other car to give up their right of way unless the driver has terrible judgment or a death wish.

I can see the argument about some cars not having enough space, but I'm not sure that's what is motivating the No U-Turn laws.

[chizzuk]

Originally Posted by brad_d

If U-turns are legal for the left-turners, then this is horrible design! I've never seen an intersection set up this way, and hope I never do....

The one right outside my apartment is like this. One cross-street is 6 lanes across plus 2 left turn lanes, the other cross-street is 4 lanes across plus 2 turn lanes. In other words, major intersection. When the 6-lane cross street has the left turn arrow, the 4-lane cross street has right turn arrows.

However, the way my apartment complex is set up, it's at the corner of these 2 streets and has 2 exits, one for each road. However, the 6-lane road has a median in the middle meaning you cannot turn left onto it from my apartment. But it is also the fastest way to the Beltway. So every morning, people from my apartment complex (9 buildings or so) make right turns, zoom across three lanes in a span of 100 feet, and use the light to make a U-turn. Given that this is the DC area, there is a near-accident roughly once every 45 seconds, but somehow we all get by.

I use the other exit, which requires making a left turn across 4 lanes of extremely busy traffic with no light, then waiting at a light that is usually very backed up and has a left turn light that is so short that if you don't go ahead and run it, it may take 3 cycles to get through. I've counted, and if nobody runs it, 5 cars can make a turn. However, if 1-2 people piggy-back on the tail of the last car as the yellow light disappears, then another person pulls out into the intersection to go through when it turns red and somebody piggy-backs on him, you can get 8-9 cars through. I get massively annoyed when the person at the front of the line doesn't pull out to go through when it turns red.

Oh, and did I mention there's usually a horde of about 10 pedestrians, many of whom jaywalk, trying to cross at the same time? It's so much fun!

[Baracus]

Originally Posted by Wheelz

Baracus, granted, everybody should be careful. But it's shouldn't be the onus of a driver with the right-of-way and executing a perfectly legal maneuver to "account for the possibility" of someone else doing something dangerous and illegal.

I would agree. In my case, u-turns are legal in NC and the onus should be on the people with the stop sign.

[Gatopescado]

"The Man" is an Ass, and suckles the Black Sperm of the Nanny-State.