Here's a Michigan Left turn design in Maryland:
http://maps.google.com/?ll=39.020213,-77.012529&spn=0.003192,0.004823&t=h&z=18&vpsrc=6 (http://maps.google.com/?ll=39.020213,-77.012529&spn=0.003192,0.004823&t=h&z=18&vpsrc=6)
Vehicles traveling on US-29 are not allowed to make left turns onto University Blvd but instead must make a right and then make a U-turn at a crossover just past the intersection. Vehicles traveling on University are allowed to make a left turn onto US-29 as there is adequate queuing space in the median.
This is nearly the exact same design as the Plano, Texas Michigan Left turn that was constructed in mid-2010:
http://maps.google.com/maps?q=plano+tx&hl=en&ll=33.070645,-96.795795&spn=0.003443,0.004823&sll=39.020351,-77.011757&sspn=0.006385,0.009645&vpsrc=6&t=h&z=18 (http://maps.google.com/maps?q=plano+tx&hl=en&ll=33.070645,-96.795795&spn=0.003443,0.004823&sll=39.020351,-77.011757&sspn=0.006385,0.009645&vpsrc=6&t=h&z=18)
Vehicles traveling on Legacy Drive are not allowed to make left turns onto Preston but instead must first make a right and then make a U-turn at a crossover just past the intersection. Vehicles traveling on Preston are allowed to make a left turn onto Legacy Drive as there is adequate queuing space in the median.
I've always envisioned a setup where you have two very wide boulevards (200 feet or more) that intersect each other. The long medians would allow enough queuing space for all left turns to be serviced at the main intersection itself without forcing left turners to make a U-turn at a crossover. Left turn phases at traffic signals would be eliminated and the simple 2-phase signals would make it a lot easier to provide dual coordination along major corridors. I guess there reaches a point where a very wide boulevard would be viewed as a couple of one-way streets though.
They're also putting one in at Oracle (SR 77) and Ina in Tucson (http://www.kold.com/story/15401652/michigan-left-coming-to-tucson) (this is the intersection Giffords was shot at, by the way)
Another indirect benefit of Michigan Lefts: They are easier (presumably) to cross as a pedestrian. Instead of dealing with up to 9 lanes at one time (1rt 3st 2lt 3st) for a busy suburban intersection, it can be compressed down to 7 lanes, that are crossed one direction at a time. That means that if there is a gap in the traffic wave, you can safely jaywalk and not worry about not making it across 100+ feet of asphalt, because you would only have to cross ~40 feet at once.
Nice to see more states finally catching on to this. Now if we can convince IDOT, I'll be happy.
Quote from: tradephoric on September 22, 2011, 05:45:22 PM
I've always envisioned a setup where you have two very wide boulevards (200 feet or more) that intersect each other. The long medians would allow enough queuing space for all left turns to be serviced at the main intersection itself without forcing left turners to make a U-turn at a crossover. Left turn phases at traffic signals would be eliminated and the simple 2-phase signals would make it a lot easier to provide dual coordination along major corridors. I guess there reaches a point where a very wide boulevard would be viewed as a couple of one-way streets though.
Dream, meet reality. http://g.co/maps/2ct9k
The one on the left was there for old Stapleton Airport, the one on the right was installed when Stapleton was made into a community.
There's been something similar for as long as I can remember in Alexandria, Virginia. Traffic coming from eastbound Duke Street (VA-236) wanting to go north on US-1 (Patrick Street, one of twinned one-way streets that make up US-1 there) has to go right onto Henry Street and then make a U-turn via a short ramp on the left around an office building. On the map below, the turnaround is just below the building with the "SLA" label."
http://maps.google.com/?ll=38.80297,-77.051191&spn=0.003198,0.008256&t=h&z=18&vpsrc=6
QuoteDream, meet reality. http://g.co/maps/2ct9k
The one on the left was there for old Stapleton Airport, the one on the right was installed when Stapleton was made into a community.
That's exactly what i was picturing! Has the same benefits as a Michigan Left design but more convenient for left-turning vehicles.
I made some quick illustrations contrasting the Michigan Left with a standard suburban arterial intersection.
(https://lh4.googleusercontent.com/-ypzwQmtmCg4/Tn0O2Zct31I/AAAAAAAABjs/v0OgUstpoUs/MichLeft1.png)
13 lanes for a diagonal crossing, with breaks in 2 places. Ideally, a ped refuge island would be built on the median of the N-S road.
(https://lh6.googleusercontent.com/-LUkRYGVyoDY/Tn0O2vni9iI/AAAAAAAABjw/mBP4WmiYqik/MichLeft2.png)
16 lanes to cross, with a break in 1 places. Ideally, the N-S median would be extended into a crosswalk and a ped refuge island cut out of that.
Found a sign for one in New Orleans: http://maps.google.com/maps?hl=en&ll=29.956203,-90.182422&spn=0.004257,0.008256&gl=us&t=m&z=18&layer=c&cbll=29.956068,-90.18238&panoid=U2IC1JewMQR-LSBAcRJVZw&cbp=12,208.64,,1,4.36
Quote from: tradephoric on September 22, 2011, 05:45:22 PM
Here's a Michigan Left turn design in Maryland:
http://maps.google.com/?ll=39.020213,-77.012529&spn=0.003192,0.004823&t=h&z=18&vpsrc=6 (http://maps.google.com/?ll=39.020213,-77.012529&spn=0.003192,0.004823&t=h&z=18&vpsrc=6)
Vehicles traveling on US-29 are not allowed to make left turns onto University Blvd but instead must make a right and then make a U-turn at a crossover just past the intersection. Vehicles traveling on University are allowed to make a left turn onto US-29 as there is adequate queuing space in the median.
This place is called Four Corners, in unincorporated Silver Spring, Montgomery County. The intersection reconstruction was completed about 10 or 15 years ago.
The State Highway Administration and its predecessor agency, the State Roads Commission, had discussed a complete grade separation of this chronically-congested intersection since the 1960's, when a short (and at the time, isolated) section of the Capital Beltway was opened to traffic in 1962 (between Md. 193 (University Boulevard) and Md. 97 (Georgia Avenue)).
All plans I have seen had been to put U.S. 29 (Colesville Road) below-grade, but the construction would have been quite disruptive, and more than a few Four Corners business owners and owners of commercial properties were opposed, as were some local citizens (though in the end, it would have led to a more pedestrian-friendly Four Corners).
As a compromise, this reconstruction was done instead.
Quote from: Zmapper on September 22, 2011, 08:18:20 PM
you can safely jaywalk
:whip: Take that, you swine! :-D
Quote from: cpzilliacus on September 27, 2012, 03:23:38 PM
This place is called Four Corners, in unincorporated Silver Spring, Montgomery County. The intersection reconstruction was completed about 10 or 15 years ago.
The State Highway Administration and its predecessor agency, the State Roads Commission, had discussed a complete grade separation of this chronically-congested intersection since the 1960's, when a short (and at the time, isolated) section of the Capital Beltway was opened to traffic in 1962 (between Md. 193 (University Boulevard) and Md. 97 (Georgia Avenue)).
All plans I have seen had been to put U.S. 29 (Colesville Road) below-grade, but the construction would have been quite disruptive, and more than a few Four Corners business owners and owners of commercial properties were opposed, as were some local citizens (though in the end, it would have led to a more pedestrian-friendly Four Corners).
As a compromise, this reconstruction was done instead.
Thank you for the info on this intersection. I guess this really isn't considered a Michigan left since traffic from University Blvd are allowed to make direct lefts onto U.S. 29. It's almost a hybrid of a town center interchange / Michigan left turn but don't know what the official name for this type of interchange would be.
If you don't mind what's your personal opinion on this intersection? Any major benefits/disadvantages?
Michigan Left's seem to be making their debut in Maryland. US 301 on the Eastern Shore has several of them, plus there was one recently put in at the intersection of MD 3 and Waugh Chapel Road near Odenton.
Quote from: PennDOTFan on September 27, 2012, 09:17:55 PM
Michigan Left's seem to be making their debut in Maryland. US 301 on the Eastern Shore has several of them, plus there was one recently put in at the intersection of MD 3 and Waugh Chapel Road near Odenton.
There's also a proposal to build one at the intersection of MD 51 and Virginia Avenue in Cumberland.
Quote from: tradephoric on September 27, 2012, 08:43:41 PM
Quote from: cpzilliacus on September 27, 2012, 03:23:38 PM
This place is called Four Corners, in unincorporated Silver Spring, Montgomery County. The intersection reconstruction was completed about 10 or 15 years ago.
The State Highway Administration and its predecessor agency, the State Roads Commission, had discussed a complete grade separation of this chronically-congested intersection since the 1960's, when a short (and at the time, isolated) section of the Capital Beltway was opened to traffic in 1962 (between Md. 193 (University Boulevard) and Md. 97 (Georgia Avenue)).
All plans I have seen had been to put U.S. 29 (Colesville Road) below-grade, but the construction would have been quite disruptive, and more than a few Four Corners business owners and owners of commercial properties were opposed, as were some local citizens (though in the end, it would have led to a more pedestrian-friendly Four Corners).
As a compromise, this reconstruction was done instead.
Thank you for the info on this intersection. I guess this really isn't considered a Michigan left since traffic from University Blvd are allowed to make direct lefts onto U.S. 29. It's almost a hybrid of a town center interchange / Michigan left turn but don't know what the official name for this type of interchange would be.
If you don't mind what's your personal opinion on this intersection? Any major benefits/disadvantages?
From the time I was about 1 year old, until after I had graduated from college in the early 1980's, I lived very near there. I moved to a new home along U.S. 29 some miles north of there (near the present-day interchange of U.S. 29 and Md. 200 (ICC)), so I have watched this area evolve for many, many years.
My personal opinion is that it helped, but that a grade-separation would have helped much more, though the severe A.M. peak period congestion here (especially southbound traffic headed for the Outer Loop (westbound) of I-495) would still be there.
Removing the left turns from U.S. 29 in both directions freed up capacity that was otherwise taken up by those movements - and because the distance between the westbound and eastbound lanes of Md. 193 was so small, there was very little storage space for traffic wanting to turn left, and those left turns (now eliminated) consumed an enormous amount of the capacity of the intersection. Making a "left" now requires a right and then a left, and the signal timing is such that it takes a fair amount of time to complete that movement.
Quote from: PennDOTFan on September 27, 2012, 09:17:55 PM
Michigan Left's seem to be making their debut in Maryland. US 301 on the Eastern Shore has several of them, plus there was one recently put in at the intersection of MD 3 and Waugh Chapel Road near Odenton.
The one at Md. 3 (Crain Highway) and Waugh Chapel Road seems to work decently.
As I understand it, the intersection was rebuilt like this because of an excessive number of "t-bone" crashes there (perhaps made worse by the 55 MPH speed limit on Md. 3).
Does anyone use the term "boulevard turn" for a Michigan left? That's the term I heard years ago in the Detroit area, when I asked for directions. Or did they just make it up?
US 301 has them now between US 50 and the DE Line. The only difference is you can turn left from US 301, but cross traffic is right out to U Turn ramp then around and right again to continue.
Quote from: roadman65 on September 30, 2012, 02:48:23 PM
US 301 has them now between US 50 and the DE Line. The only difference is you can turn left from US 301, but cross traffic is right out to U Turn ramp then around and right again to continue.
These were also done to reduce the number and severity of T-Bone crashes (posted speed limit on U.S. 301 on the Upper Shore is 55 MPH but average speeds are probably more like 70 MPH).
QuoteDoes anyone use the term "boulevard turn" for a Michigan left? That's the term I heard years ago in the Detroit area, when I asked for directions. Or did they just make it up?
I've never heard it called a "boulevard turn" before but it's probably as good a description as any. It's affectionately known as "flipping a bitch" around here.
Superstreets are popping up more and more in America but full blown Michigan lefts are nearly non-existent outside of Michigan. Here is an example of each type of design:
Michigan Left intersection:(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi478.photobucket.com%2Falbums%2Frr144%2Ftradephoric%2FTransportation%2520Pictures%2FMichigan%2520Lefts%2FBigBeaverCrooksMichiganLeft.jpg&hash=231002276ee099285c7f236432b357823eddce7e)
Superstreet intersection with direct left turns:(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi478.photobucket.com%2Falbums%2Frr144%2Ftradephoric%2FTransportation%2520Pictures%2FMichigan%2520Lefts%2FBigBeaverLakeviewSuperstreet.jpg&hash=530fb7266d6c921fc82ef19c03b522890dafc41f)
Superstreet intersection with no direct left turns:(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi478.photobucket.com%2Falbums%2Frr144%2Ftradephoric%2FTransportation%2520Pictures%2FMichigan%2520Lefts%2FSuperstreetBigBeaverTroyCenter.jpg&hash=e0316f038bfe50f30d41165caaa91c19371020e1)
FDOT is sort of doing it from FL 528 to Oakridge Road on Orange Blossom Trail and all last Spring FDOT had done it from Oakridge to I-4 getting rid of the center turn lane for safety reasons. You cannot make any lefts out of side streets and driveways. Most is being turned into right in and right outs, but every so often a U Turn lane and median break is needed to make the crossover. Those driveways directly across from the U Turns can actually have left turns into them, but still a right out. Then the signalized intersections are left the same with added Left Turn signals to accomodate the new traffic doubling back where there was none before like at 39th Street.
Then US 192 in Kissimmee has them as well in St. Cloud. Only signalized intersections allow full crossovers and full turns from St. Cloud to Orange Lake west of Disney.
:banghead: