Y-shaped driveways

[Scott5114]

Lately I've noticed a lot of new stores and restaurants and such in my area have triangular medians installed in their driveways, creating a Y-shaped driveway. Since each branch of the Y is one lane, the intended effect appears to be forcing only right turns into and out of the driveway. (However, since there is usually no signage to accompany this, people will often turn left upon exiting anyway.)

Does this setup occur in your area? Why did it proliferate so suddenly?

[DaBigE]

We've had a handful installed.  Usually, however, they're promoted by the municipality in order to control access and improve safety.  In that regard, they have been properly signed as part of the local requirements.  I haven't seen too many (any) put in voluntarily as merchants usually want as much access as they can possibly get, and then some.

Either way, no matter how much signage is or is not placed, median or no median, some drivers are hell-bent on making the turn they want to make.

[Brian556]

There are some like this in our area. Many are done this way because they are close to an intersection; and left turns into/out of them would be unsafe. Most are signed properly. However, the one at Autozone on US 77 in Denton is not signed at all; and morons always go the wrong way.

[Perfxion]

Around Houston a lot of those are put in on the feeder roads, but since its one way road, its kind of pointless.

[realjd]

They use those around here to help enforce right-turn-only (with no-left-turn signage), or to put a barrier in a long series of right turn lanes so people don't use them for through traffic.

[Alps]

Some have it, some don't. No idea why they would bother, it's extra expense to the business. The only place it makes sense is on a higher-speed roadway when you have RIRO, and plenty of these places are not on higher-speed roadways.

[NE2]

It's part of access management, required by the government in exchange for adding driveway access. Traffic flows better when you can't just turn left anywhere.

[bsmart]

They probably do it because they are required to by the local highway department. I'm on the local Planning Commission and I know that on our Main Street (US 40A) SHA isgoing to require a couple properties to have Right turn only exits and entrances when they are developed

[D-Dey65]

A friend of my family has one, because there a huge utility pole in the middle of the driveway.

[Duke87]

You know, I never considered that it might be municipally required. I always assumed that managing a private driveway was entirely up to the owner.

In my experience this strategy is typically only employed when there is another exit (usually onto a side street) which allows the missing movements, or when the road has a median barrier such that all businesses on the other side require a U-turn to get to.

Respect for them varies by jurisdiction... in New Jersey people do not. In Connecticut people usually do, though there are quirks. There's a McDonalds on US 1 in Stamford (CT) which has this treatment on its main driveway. The exit is marked with a "no left turn" sign. The corresponding entrance is not. As such, you will see people willingly making left turns into this driveway, but left turns out of it, not so much. This is also helped by the fact that the way the driveway is shaped and the way the street is striped mean that making a left turn out of the driveway is blatantly against geometry but making a left turn into it is not unintuitive.

[NE2]

I doubt there's any law against turning left at one of these without the proper signage. Otherwise you couldn't turn left at a Y intersection.

[Alps]

But see, there's no need for the island on a low-speed road if you just put up a pair of signs - NLT from the street, NLT from the driveway.

[Scott5114]

Well, yes, but some people need the extra reminder.

[Darkchylde]

A business that just opened up near my place has one of those.

I ignore it going in. It's too much of a hassle to fight the traffic on the other road with the traditional entrance. Don't need to ignore it leaving, as it's a right turn to my place.

[txstateends]

A new shopping center in Dallas (http://g.co/maps/qtxpb) has a Y-driveway off a cloverleaf between Loop 12 and Skillman St.  A jersey barrier was installed between the cloverleaf lanes so no one exiting the shopping center driveway would exit left, only right.  The driveway was supposedly controversial as none was there before, and the original shopping center layout called for only access from Loop 12 and from Skillman directly.

[bsmart]

But see, there's no need for the island on a low-speed road if you just put up a pair of signs - NLT from the street, NLT from the driveway.

Sure, people ALWAYS pay attention to traffic signs.  Even with Islands, and signs, and even big white arrows on the pavement there are some people who come in what is obviously the outbound chute because it will save them a few seconds.

[J N Winkler]

Lately I've noticed a lot of new stores and restaurants and such in my area have triangular medians installed in their driveways, creating a Y-shaped driveway. Since each branch of the Y is one lane, the intended effect appears to be forcing only right turns into and out of the driveway. (However, since there is usually no signage to accompany this, people will often turn left upon exiting anyway.)

I haven't noticed any in Wichita, but this is mainly because I tend to avoid the areas of town (and we do have them) that are being considered for access management measures.

Does this setup occur in your area? Why did it proliferate so suddenly?

Access management has become fashionable.  TRB now has an Access Management Manual (and accompanying software distribution which can be obtained on CD or downloaded) that came out about five years ago and is, I think, still available from their website.

[kphoger]

I haven't noticed any in Wichita, but this is mainly because I tend to avoid the areas of town (and we do have them) that are being considered for access management measures.

The one that came immediately to mind was the Walgreens at Douglas and Hillside.  The entrance immediately to the south of the interscetion has a wye intended to discourage left turns.  There are no signs, and people routinely ignore the suggestion (and a suggestion is all it is, as it's quite small).

[Brandon]

We have thousands of these around Chicagoland.  Usually, the engineers call them "porkchops" due to the shape of the island to regulate traffic flow.  Unless there is a barrier separating the two sides of the roads, undoubtedly, even with signage, people try to turn left into them and out of them.  The Chicago attitude with them that I've seen tends to be "I want to turn into the driveway, but there's a no left turn sign there.  Ah, fuck them, I'll turn left anyway."

[kphoger]

I haven't noticed any in Wichita, but this is mainly because I tend to avoid the areas of town (and we do have them) that are being considered for access management measures.

The one that came immediately to mind was the Walgreens at Douglas and Hillside.  The entrance immediately to the south of the interscetion has a wye intended to discourage left turns.  There are no signs, and people routinely ignore the suggestion (and a suggestion is all it is, as it's quite small).

Make that Central and Hillside.  D'oh!

[BamaZeus]

We have a few of those around the city, yet it doesn't stop anyone from trying to turn left across 6 lanes of traffic to go the other way.  *Facepalm*

[UptownRoadGeek]

We have them around NOLA, but I don't see the point since you usually can only enter and exit right around here anyway. It's rare to be able to turn left into or out of something.

[kendancy66]

The house I grew up in had an h shaped driveway