Trips where exiting and U-turning is the fastest route

[kphoger]

Before they rebuilt the Kellogg/I-235 interchange here in Wichita, I used to leave the westside mall, get on WB Kellogg, then do two loop ramps of the cloverleaf in order to head EB back home.

Was it actually faster, or just more fun?

Faster.  Completely avoided a couple of stoplight intersections, including the SPUI hybrid thing at Kellogg & West.

[kphoger]

The total degrees around the circle is 360, but the net degrees turned, relative to your starting position, is only 180.

But it isn't. I have gone around the entire circle.

I think we need an illustration.

[webny99]

Before they rebuilt the Kellogg/I-235 interchange here in Wichita, I used to leave the westside mall, get on WB Kellogg, then do two loop ramps of the cloverleaf in order to head EB back home.

Was it actually faster, or just more fun?

Faster.  Completely avoided a couple of stoplight intersections, including the SPUI hybrid thing at Kellogg & West.

I can see that. So now that it's been redesigned, you're stuck with the SPUI?

[kphoger]

Before they rebuilt the Kellogg/I-235 interchange here in Wichita, I used to leave the westside mall, get on WB Kellogg, then do two loop ramps of the cloverleaf in order to head EB back home.

Was it actually faster, or just more fun?

Faster.  Completely avoided a couple of stoplight intersections, including the SPUI hybrid thing at Kellogg & West.

I can see that. So now that it's been redesigned, you're stuck with the SPUI?

I think so, yes.  I've only gone to that area (Guitar Center) once or twice since the rebuild, and I do indeed think I used West Street to get home.

[Rothman]

The total degrees around the circle is 360, but the net degrees turned, relative to your starting position, is only 180.

But it isn't. I have gone around the entire circle.

I though webny's explanation was excellent.  You have only rotated 180°.

Here's another discussion:

https://www.merriam-webster.com/words-at-play/doing-a-180-vs-doing-a-360-usage-difference

[DTComposer]

The total degrees around the circle is 360, but the net degrees turned, relative to your starting position, is only 180.

But it isn't. I have gone around the entire circle.

Yes, you have traveled 360 degrees around a circle (from twelve to twelve on a clock face, say), but the orientation of your car has only changed by 180 degrees (facing north to facing south, say). That's what webny99 meant by net degrees. Regardless of your path (simple u-turn, roundabout, three-point turn), at the end of the path you are facing 180 degrees from your original orientation.

This may be a matter of semantics, but the common parlance for ending up facing in the opposite direction is "doing a 180."

[kphoger]

For what it's worth, doing an about-face at a roundabout does NOT have you going "around the entire circle".

[GaryV]

For what it's worth, doing an about-face at a roundabout does NOT have you going "around the entire circle".

Also, the greater than 180 degrees that you make on the green path are partially offset by the opposite direction degrees when you follow the two blue paths.

[jp the roadgeek]

Getting to New Britain Stadium from CT 9 South.  The recommended route is to get off the Exit 25 (Future 35), take a left on Ellis St, and then another left onto CT 71 South to get to the stadium about 3/4 of a mile down the road.  However, the two left turns often cause backups.  It's easier to stay on CT 9 South and get off Exit 23 (Future 33) Christian Lane, then get back on CT 9 North to Exit 24 (Future 34) SR 571, which is a partial interchange, then get off Exit 1 (CT 71).  You can cut straight across into the stadium parking lot. 

[kphoger]

But what I'm mostly looking for here is examples that occur thanks to unusual ramp configurations or partial interchanges ...

Does this count?  There's a rebound interchange here in Wichita that we use every time we head home from church:

https://goo.gl/maps/7aUkycrXX8Ycy9DE9

On rare occasions, we also do a similar thing to get to church:

https://goo.gl/maps/ewGKgvFPN5MLL5Mx7

[jeffandnicole]

Oh also, there are a few times when exiting a local gas station parking lot, that traffic backs up trying to take a left back onto the main drag.  I bypass all this traffic by turning right and using a roundabout a half block down.  I turn 360 degrees, and pass everyone still in line.

turning 360 degrees?  That leaves you in the same direction.

If I enter a roundabout, and go 360 degrees, I am going back where I came from correct?

Nope.  Only 180 if you exit where you entered.

That makes no sense.  A roundabout is a circle.  If I turn right, I go 90 degrees around that circle...go straight is 180...go left is 270...

You're not going 90 degrees, especially at that first and last segment.  90 degrees would indicate you entered the roundabout, then pulled fully out at the next leg completing a right turn.  You're at most making a 45 degree turn to the right before straightening out to continue in the roundabout (net, 0 degrees), then turning left (90 degrees).  Then turning left (90 degrees), then making a 45 degree turn to the left before straightening out as you leave the roundabout (net 0 degrees), which equals 180 degrees.

[mgk920]

Doing a 180 degree 'U' turn at a roundabout as part of turning into or out of an adjacent or nearby minor intersection or commercial driveway is kind of a normal traffic thing.

As for the OP's query, wouldn't that that also be a kind of normal traffic thing throughout Texas, as well as various scattered other places, such as in parts the Detroit, MI metro area?

Mike

[webny99]

But what I'm mostly looking for here is examples that occur thanks to unusual ramp configurations or partial interchanges ...

Does this count?  There's a rebound interchange here in Wichita that we use every time we head home from church:

https://goo.gl/maps/7aUkycrXX8Ycy9DE9

On rare occasions, we also do a similar thing to get to church:

https://goo.gl/maps/ewGKgvFPN5MLL5Mx7

Sure. That's very similar to the first example in the OP. I don't find it quite so interesting as some of the other examples since it's custom built for U-turning traffic, but it counts all the same.

As for the OP's query, wouldn't that that also be a kind of normal traffic thing throughout Texas, as well as various scattered other places, such as in parts the Detroit, MI metro area?

Yes (see above), but those often involve using the service road on one side or the other. Less common are cases where you're using the freeway mainline in both directions, like my second and third examples and the first reply.

[ibthebigd]

Until a traffic signal was installed at the end of the ramp from I-64 eastbound to the US 460/KY 11 exit in Mt. Sterling, if you wanted to turn left toward Flemingsburg, it was faster to turn right and then U-turn at the next signal. Traffic on US 460/KY 11 was consistently heavy so as to greatly inhibit the ability to turn left onto westbound 460/northbound 11.

Yes!

I'm going to use an example HB had on another thread going from I-264 to I-65 south in Louisville it can be faster to go to the airport exit and go back to I-65

That loop ramp is horrible.

SM-G996U

[JKRhodes]

I drove for Uber and Lyft in Tucson for some time. When transporting passengers from the airport to the northwest side of town, the nav app and local signage directs drivers onto Kino Parkway, then to the access road to cross Ajo Way onto the I-10 onramps there. I found it was much faster, and a much safer merge, to go beyond the access road, make a U-turn, and merge onto I-10 from the onramp at southbound Kino Parkway.

https://goo.gl/maps/sVDirgsFFW8zUQpU7

Similarly, two miles away, the onramp from Irvington to I-10 West is horrible. It's much better to utilize the ramp from Southbound Palo Verde Road.

[CtrlAltDel]

You're not going 90 degrees, especially at that first and last segment.  90 degrees would indicate you entered the roundabout, then pulled fully out at the next leg completing a right turn.  You're at most making a 45 degree turn to the right before straightening out to continue in the roundabout (net, 0 degrees), then turning left (90 degrees).  Then turning left (90 degrees), then making a 45 degree turn to the left before straightening out as you leave the roundabout (net 0 degrees), which equals 180 degrees.

The whole situation is weird, because a straight angle is 180 degrees, and we would generally call that doing nothing.





What appears to be happening is that the angle of a turn is measured perpendicular to the direction of travel instead of alongside it, like a regular angle is, which is something I've never thought about before.

[mariethefoxy]

There's a spot on the Northern State Parkway by Exit 31A where there is an extra ramp to Glen Cove Road North (a holdover from the previous configuration of this area), people often will turn right since its a No Left Turn, then immediately make a U Turn at that next traffic light for NY 25 rather than go up a bit for the Exit 31 ramp since you wind up sitting for two long traffic lights for NY 25B and NY 25 if you do it that way, and going down the Meadowbrook Parkway to Old Country Road to get to Glen Cove Road is often much more congested because of all the Mall and Mineola/Nassau county courts and offices traffic.

[kphoger]

The whole situation is weird, because a straight angle is 180 degrees, and we would generally call that doing nothing.

What appears to be happening is that the angle of a turn is measured perpendicular to the direction of travel instead of alongside it, like a regular angle is, which is something I've never thought about before.

*mind blown*

So, simply continuing straight ahead, according to |SEWIGuy|'s reckoning, is a 180° turn.