urbanMSP

I started a map of locations I think are good candidates for conversion to roundabouts, or possibly some sort of shared-space treatment -- places where stop lights are more of a hindrance than help. I decided to make an open map where anyone can drop some placemarks as suggestions:



A few starter locations include complex intersections like the 6-way Como Ave/Dale St/Front St intersection in St. Paul, the 5-way Como Blvd/Como Lake Dr/Wheelock Pkwy/Maryland Ave intersection by Como Park, and the triangular mess of Franklin Ave/Cedar Ave/20th Ave/Minnehaha Ave in Minneapolis. Franklin/East River Pkwy/27th Ave is also included -- I think a roundabout design was rejected there for a rebuild a few years ago because it "wouldn't fit" in the space (well, then the design was probably too big, or they were unwilling to take adjacent empty land [=parking lots])

I don't think snow is going to be a problem on LED streetlights.

1) The emitters point straight down, as opposed to towards the side with a visor.
2) An LED streetlight is on constantly as opposed to part of the time, and
3) An LED streetlight uses (and emits as heat) considerably more power than a traffic signal. AN LED traffic signal ranges from about 8-18 watts (depending on the color, size, and shape), incandescent traffic signals consume 69-150 watts. By contrast an LED freeway streetlight uses 190-215 watts (replacement for 250 and 400 watt high pressure sodium).

As far as snow on traffic lights, I haven't heard anything officially, but Colorado, which gets a lot of wet, sticky snow, has had some success with putting ventilation holes in the visors which keeps air moving.

Oh wow that map filled up quickly. I actually think the intersection of Ford Parkway/46th Ave/46th St would make for a good roundabout to help calm traffic coming off the bridge (where many people speed) and deal with the awkward intersection.

Wholeheartedly agree with Cedar Ave/Nokomis - using a roundabout here to mark the freeway -> street transition is important.

Finally, if we're talking large, engineered roundabouts outside the core cities... the wye at 101 and Flying Cloud Dr just north of the river would be a great candidate, IMO. The series of lights there (along with the intersection just west) do very little.

I like the Diamond Lake Road/Portland Ave intersection as well. Because it is a T, there's a phase where NB Portland gets double the green time because of the left turn arrow to WB DLR. That's great if you're going NB on Portland, but the traffic volume in all directions seems much more even than that, causing SB and EB drivers to get quite anxious waiting for the light to turn when no one is coming NB. There's also the "everyone gets red" phase when one of the beg buttons has been pushed.

A roundabout would smooth out traffic nicely, but I'm curious what effects it would have on the Portland/54th and Portland/55th T intersections immediately N and S of here. 54th would almost have to be another roundabout, lest NB Portland back up into the DLR roundabout when that light is red. 55th is lightly-enough used that it can stay as is, I'd reckon.

The other benefit of a roundabout(s) here would be the calming of evening commuter traffic that has a tendency to fly SB past *extremely* busy athletic fields at Pearl Park. If drivers know they have to slow for the roundabouts, they might not hustle to those lights quite as quickly. I can't count the number of times I've feared for the lives of families dashing across Portland to get to their soccer matches.

Portland and Diamond Lake: Another option is the city of Minneapolis could get with the times and start installing flashing yellow arrows and vehicle sensors. The signals on Lyndale were just put in last year and still don't have either:

Flying Cloud Drive: I really wish they'd build an interchange like they originally planned, but a roundabout has been confirmed for next year or the year after (I forget exactly). It's linked to the project to expand MN 101 to 4 lanes across the river, which Shakopee insisted happen as part of the flood mitigation project that there was special funding for.

I drive 101 from Chan to the river every day, and can say with absolute certainty that widening it to 4 lanes is completely unnecessary - any congestion is only caused by the lights on the north side. This will have a dramatic impact on inducing more car demand.

Something has to happen at Franklin/Cedar/Minnehaha/20th. I don't know if roundabout(s) are the answer, but they certainly could be. The major issue there is that roundabouts are not great for pedestrians, since traffic never "stops". Not that the existing situation is remotely pedestrian-friendly, but at least right now a disabled person can hit a beg button and make it across safely. I drive through the Portland-66 roundabout every day (and sometimes walk through it at lunch time)...that thing is not a pedestrian paradise by any means. Any changes to Franklin/Cedar/Minnehaha/20th would need to carefully consider the needs of pedestrians, transit users, and bicyclists much more than a roundabout in suburbia or outlying parts of the city.

http://bicycledutch.wordpress.com/2013/ ... oundabout/

This looks to be pretty transit, bike, and pedestrian - friendly to me. I like that the tram gets priority through the center (and this could theoretically be done with buses as well).

I looked it up on Google Maps and here is is: http://goo.gl/maps/kAWX . Property line to property line is ~63' on the E-W street and ~96' on the N/S street (that contains the tram in the middle). Diameter of the roundabout itself, including the cycle track, is 180'. (it is also shown in the satellite image handling a semi-truck through the curve).

Seems like intersections that could handle this size based on current ROW dimensions and lane requirements:
- Franklin/E River Pkwy/27th
- Cedar/Nokomis Pkwy/Edgewater if park space can be used up
- Ford/46th/46th (2 thru-lanes on Ford would be akin to 2 thru + tram? not sure)
- Dale/Como/Front (though some parking lot space might need to be acquired)

Ones that wouldn't need something so serious:
- Diamond Lake/Portland
- Godfrey/46th Ave

I'd be fascinated to see this beast overlaid onto some of the intersections you're talking about.

^OMG the "Large Dutch Turbo Roundabout" (which could double as the name of a weird sexual activity) is insane. Look at that thing (at the bottom of the linked page)

P.S. I don't think the Google Maps link is correct. It goes to a small city in France...

Here's the address of the dutch one in the city: 1052 LE Amsterdam, The Netherlands .. Sorry the link didn't work

Also, I'd be willing to do an overlay of the roundabout at 50% transparency on these intersections, but I'm at work with no Google Earth and am pretty busy tonight. I would also be curious.. my initial estimation was based on pure distance measurements without regard to grade, angles of approach, etc as I don't know how they affect build-ability or required sightlines.

Following up my post from before... Took a snapshot of the Amsterdam version with a 100' line for reference, overlaid and scaled it in several MSP locations:

Franklin & E River Rd: http://flic.kr/p/fG3RyQ
Ford Parkway, 46th, and 46th: http://flic.kr/p/fFLgD4
Como & Dale: http://flic.kr/p/fG3RJ5
Cedar/Nokomis: http://flic.kr/p/fFLh38 (wish I had moved it further south but shows the feasibility nonetheless)
Cedar/Franklin/Minnehaha: http://flic.kr/p/fFLhiz

Seems like they're mostly reasonable, with the Ford Pkwy/46th intersection having the most obvious ROW impacts. It's tough to say how a roundabout would work at intersections with the third street entering at a diagonal, but I'd be curious to have some of these tested out.

Edit: Fixed the privacy settings on them for viewing, my bad.

Are those protected somehow? It says I have to sign into Google first to view them.

Very interesting. Thanks for taking the time to work through this.

The major issue there is that roundabouts are not great for pedestrians, since traffic never "stops".

Roundabouts are absolutely great for pedestrians, since the traffic is going slower. Put crosswalks about 20 yards from the entrance of the roundabout and make sure they all have the signs saying "State Law. Stop for Pedestrians in Crosswalk".

People are confusing roundabouts with Minnesotans' complete disregard for the law about stopping for pedestrians when it's required.

Evidence based posting: http://ajph.aphapublications.org/doi/pd ... .93.9.1456

I think there's a lot of truth to both points of view -- I've definitely gone way too fast through some roundabouts that I wasn't expecting, partly because I'm the unusual driver who follows the speed limit closely rather than generally "going with the flow" or driving at a speed that "feels right". If there isn't an appropriate speed warning ahead of time, I may not slow down until the last second. (There are some places where the speed limit really is the 85th percentile speed, or even higher than that, rather than the 15th percentile speed or lower like it seems to be on our local highways and many arterials.) I've been working on retraining my driving habits a bit, but I also don't drive nearly as often as I used to.

One of my scariest experiences with roundabouts was when I took a trip to Madison, WI a few years ago. They were working on a new freeway alignment for U.S. 12 around Baraboo -- when I got off I-94 and started heading south, the traffic all suddenly went through three roundabouts, and people must have been flying through them at 45 mph. People had just gotten off an Interstate and were still in a freeway mode of thinking. The fact that it was a construction zone didn't help, but those roundabouts really seemed to pop up out of nowhere.

So roundabouts can work well, but they really need to be placed in the right context -- There needs to be some design feature that gets people to slow down and pay attention even at times when there aren't pedestrians around. Otherwise drivers will take the opportunity to go as fast as possible. I personally have trouble even noticing pedestrians waiting at crossings if my speed is only up around 30-35 mph, so the approach speed design has to be fairly low, as well as the design speed of the roundabout itself, since you need to be paying attention both at the entrance and exit.

Most roundabouts have a pedestrian refuge island on the approaches, but some smaller mini-roundabouts probably won't.

And before I forget, I personally don't really like how roundabouts force pedestrians pretty far away from the center of the intersection in order to cross. People like walking in straight lines, and every deflection away from the line you want to walk makes the trip less enjoyable and less likely to occur again. But that goes hand-in-hand with my earlier point, since smaller roundabouts have lower design speeds.

Just went thru one in Forest Lake; that was scary. Like the Indianapolis 500!
I don't see how a ped could survive, my focus was on trying to not get run over by the native's 4x4's- seriously.

It will be interesting to see how the pedestrian focus in the TH7 Louisiana Avenue project's heavy roundabout usage is affected. Lots of trails and sidewalks among the multiple roundabouts along Louisiana.

I always thought it was odd that intersection had better pedestrian markings than most downtown and uptown Minneapolis streets.