About a Roundabout

[ndavies]

Retroit you're very wrong. Roundabouts are far more efficient for 4 way intersections than lights or stop signs. They allow more cars through with fewer waits. They are far safer.

From http://www.iihs.org/externaldata/srdata/docs/sr3505.pdf

Researchers
at Ryerson Polytechnic University, the Institute,
and the University of Maine studied
crashes and injuries at 24 intersections before
and after construction of roundabouts.
The study found a 39 percent overall decrease
in crashes and a 76 percent decrease
in injury-producing crashes. Collisions involving
fatal or incapacitating injuries fell as
much as 90 percent.
These findings are consistent with those
from other countries where roundabouts
have been used extensively for decades.
They also are consistent with preliminary
studies of U.S. roundabouts.
The safety benefits don’t come at the expense
of traffic flow. In fact, where roundabouts
replace intersections with stop signs
or traffic signals, delays in traffic can be reduced

by as much as 75 percent.

They are not a trend. They are the future. While not appropriate for every intersection they eliminate many of the problems associated with intesections. Expect to see many more intersections replaced with roundabouts.

[Todd_Scott]

It's too bad they can't put the kind of signals that you have to activate. Pedestrians could activate the signal if the traffic was too bad or they were unable to get across in a reasonable amount of time.

That's what they are implementing in West Bloomfield. The last I heard it will be a ped-actuacted crosswalk just outside of the roundabout. The problem with high-volume roundabouts is there are no clear gaps that allow some pedestrians, especially the seeing impaired, to cross safely.

On today's West Vernor walkability audit, the consultant Dan Burden recommended some roundabouts to improve safety. Traffic engineering participated in the audit and has applied for safety funding for a portion of West Vernor in this area. So, there's a chance we'll start seeing more roundabouts in Detroit.

[NoHeartAnthony]

Retroit is the wrong type of white person. You would think that he would know that in Europe, roundabouts are used in place of 4 way stops and they are very efficient.

[urbanophile]

Roundabouts are very popular around the country. Modern roundabouts are not to be confused with old school traffic circles like you see on the east coast. There are about 1,000 or so modern roundabouts in the United States and they are being aggressively deployed in may communities. Carmel, Indiana, a suburb of Indianapolis, has 50 of them. And other Indianapolis area communities are rapidly deploying them. Carmel is even replacing six at grade intersections on a major arterial with roundabout interchanges. I have driven through the first two they completed and can attest that they are a joy to use compared to what was there before. Wisconsin is also looking at a major roundabout interchange deployment plan.

[Johnnny5]

Retroit is the wrong type of white person. You would think that he would know that in Europe, roundabouts are used in place of 4 way stops and they are very efficient.

"Wrong type of white person"? WTF is that supposed to mean?

[Bearinabox]

"Wrong type of white person"? WTF is that supposed to mean?

I assume it's a reference to Stuff White People Like.

[Meddle]

Seems like they would require a much, much larger footprint than a standard 4 way intersection. That may be fine for rural or suburban areas under new construction, but for many places in the city, it seems like there would have to be a lot of building demolition to clear the right-of-way.

[Novine]

"There's a roundabout in Novi, on Taft Road between 8 and 9 Mile. Not sure if it was needed there."

It's in Northville.

Another benefit of a roundabout is that when you lose power, the intersection functions as normal. As for it being a trend, modern roundabouts didn't start in Michigan, we're several years behind other places in the country that have been using them at all kinds of intersections.

[bdglsmn]

I have raced cars all of my life, I race motorcycles currently, My street bike will run 185mph. I have driven cross country many times [[most times by myself) in a truck or RV. and I aint afraid of nothing on the rode...except... that Lee Road exit off of 23 in Brighton. Just typing this right now is inducing an anxiety attack. Whoever the person is that thought of that "thing" should be tarred and feathered right in the middle of it.

[texorama]

Having come within a few inches of being T-boned in Dearborn a few weeks ago, I am a strong supporter of roundabouts.

[Det_ard]

I have raced cars all of my life, I race motorcycles currently, My street bike will run 185mph. I have driven cross country many times [[most times by myself) in a truck or RV. and I aint afraid of nothing on the rode...except... that Lee Road exit off of 23 in Brighton. Just typing this right now is inducing an anxiety attack. Whoever the person is that thought of that "thing" should be tarred and feathered right in the middle of it.

Twice I found myself being spit back out on to US-23 before I learned the area. I like roundabouts but that one is a textbook case on how not to do it.

[Stosh]

Having some experience using roundabouts, one observation that I'd make is that one has to have an idea where one wants to go in order to effectively use a roundabout in most cases. People that get in the wrong lane for the action they need to take just complicate things.

I can tolerate roundabouts, except in the case of Dupont Circle, Washington DC. Not really a roundabout, but you are better off paying a cabbie to navigate that. Just don't watch. It's kind of like watching sausage being made.

[RO_Resident]

As others have mentioned, most of the roundabouts are the 'modern roundabout' type. The inner circle has a relatively small radius, entering traffic is forced to enter at a tangent angle, and the traffic within the circle has the right-of-way.

Some older designs [[like you find on the East Coast) operate more like T-intersections. The inner circle also has a larger radius, which allows free flow traffic to reach higher speeds.

Why do you see more roundabouts these days? For light to medium traffic loads, they can move a lot of traffic trough the intersection. They tend to fit in the same land area as traditional intersection with turn lanes. And they spare the expense of putting up a signal, which starts at $30 to $50,000 for the lights, masts, booms, wiring, etc.

[Meddle]

Y'all are making me glad I don't live there anymore. I'm sure I'd be going postal and you'd be reading about me in the paper.

[bibs]

Roundabouts are normally applied to intersections where there is a large volume of traffic that traffic lights can't handle without backups. The 18 mile and Van Dyke intersection is great example. Michigan seems to use them where appropriate. Spent some time in the UK. On a rural highway in the US, you can time the lights never stop. In the UK, YOU have to stop at EVERY roundabout which is SO annoying! But they work just fine during a war or during a black out.

[Todd_Scott]

Seems like they would require a much, much larger footprint than a standard 4 way intersection. That may be fine for rural or suburban areas under new construction, but for many places in the city, it seems like there would have to be a lot of building demolition to clear the right-of-way.

That is not the case, at least along the very urban W. Vernor business district in Southwest Detroit. The roundabouts that were discussed would fit within the existing intersections. The exception is if you need to accommodate 18-wheelers making the equivalent of a left-hand turn.

[Ltdave]

Just cause all of Europe has them

fixed it for you....

[andyguard]

I believe that MDOT is planning on building a few roundabouts in Port Huron as part of the Blue Water Bridge Plaza project during the reconstruction and rerouting of a number of roads and bridges.

[reddog289]

I can handle the one on Geddes with no problem, Yet the one at Lee Rd,I will be ready for the grave before I get that one.

[Gistok]

I wonder if the crazy intersection of Gratiot/E. Warren/E. Grand Blvd. would make a good candidate for a large roundabout? It's probably the east side version of the west side Grand River/Trumbull/MLK Blvd. junction.

Then again.... E. Warren is a one way street [[westbound) at that intersection... and I bet that a one way street could be very dangerous as part of a roundabout [[unless it was strictly an exitway coming off a roundabout).

[dnvn522]

That is not the case, at least along the very urban W. Vernor business district in Southwest Detroit. The roundabouts that were discussed would fit within the existing intersections. The exception is if you need to accommodate 18-wheelers making the equivalent of a left-hand turn.

An Dan Burden probably expects any 18 wheelers to just go elsewhere, no matter what the design.

[Funaho]

That is not the case, at least along the very urban W. Vernor business district in Southwest Detroit. The roundabouts that were discussed would fit within the existing intersections. The exception is if you need to accommodate 18-wheelers making the equivalent of a left-hand turn.

What locations would those be? I live in the area [[Scotten & Vernor, roughly) so I'm very curious about what the plans are.

New sidewalks, new streetlights and finding some way to move parking off of Vernor would do wonders for the area...

[Todd_Scott]

We started at Armando's and worked our way west to Dragoon. And keep in mind that there are no plans. This was merely an audit that resulted in suggested improvements.

Dan mentioned the intersection of Clark and Vernor might make for a good roundabout. It would serve to keep speeds at their posted limits while drawing people westward from Mexicantown into the West Vernor Business district.

Dan is a firm believer in on-street parking. It requires far less space than parking lots and it helps provide a buffer between vehicle traffic and pedestrian areas.

He has a long laundry list of changes beyond streetscaping and painted bike lanes. The City of Detroit, Southwest Business District Association, Southwest Solutions, MDOT, and others were there to take notes and hopefully push some of this forward.

[Funaho]

I just can't imagine a roundabout anywhere along Vernor without tearing out buildings. It's already pretty tight as it is. This is also why I mentioned the street parking...some days it's downright dangerous to try to park and get to/from your car along there. Too much traffic for only two travel lanes, especially on weekends or if there's an event going on.

Still, I'd love to see something happen with this area. It has SO much potential.

[Todd_Scott]

I just can't imagine a roundabout anywhere along Vernor without tearing out buildings. It's already pretty tight as it is. This is also why I mentioned the street parking...some days it's downright dangerous to try to park and get to/from your car along there. Too much traffic for only two travel lanes, especially on weekends or if there's an event going on.

He actually measured the curb-to-curb distance on that intersection to make sure it would fit. Keep in mind that not all roundabouts are the same size.

As for the parking, the bike lanes would actually improve it by creating more of a safety buffer. The car lanes would be visually narrowed [[slowing them) and kept more to the center. As you know, the vehicle lanes are poorly defined right now.

The key is not to reduce traffic flow, but to slow it and keep it moving at a more consistent pace by replacing stop lights with roundabouts.