cars used to park in the striped area on Sundays, but for the past year DC has prohibited the practice.

If that's true then there's a whole lot of violation going on. I live a block away and people always park around the traffic island on Sundays.

by Steve on Jun 2, 2009 11:40 am  

Based on traffic volumes, the multiple intersection legs, and the space available, a roundabout may be the better long-term option.

by Froggie on Jun 2, 2009 12:15 pm  

can you get klein's opinion on a circle or roundabout?

by IMGoph on Jun 2, 2009 2:02 pm  

I live a few blocks away and walk through this intersection on my way to and from work/the busy stop. It was only a matter of time before this happened. Rarely do cars stop at the right turn off 15th, red light or not, walk sign or not. I've noticed that the stop line has been painted to give a clear walkway for pedestrians. At the very least, wouldn't it be relatively cheap and easy to create a speed bump in the far right lane on 15th before that turn?

by belmontmedina on Jun 2, 2009 2:10 pm  

I like that roundabout idea.

by NikolasM on Jun 2, 2009 2:52 pm  

Roundabouts are a disaster in urban areas thanks to their sending a random scattergun of high-speed accelerating traffic at all exits all the time. And once you make the roundabout large enough to deal with vehicles, you end up deflecting pedestrians all over the place. You don't want this British blight in American cities.

by James D on Jun 2, 2009 5:10 pm  

Urban roundabouts work best when no stop signs are involved. I've seen them used in use on the other side of the pond and they definitely work better than ours (such as Dupont Circle) where we tend to put stop signs or redlights up. There are definitely some crossings where crossing just isn't safe ... A balance between driver's needs and pedestrian's needs should be found. We shouldn't automatically say "let's take away that traffic lane". With all the crossings in this area, it might make more sense just to put up barrier or the like and close that crossing to pedestrians. Both options should be studied ... including determining which will have the greater impact. For exampt if we find that 100 pedestrians a day use that crossing, but 10,000 car with 10,000 plus people in them use that lane, then it's a no brainer that that crossing gets closed and the 100 use other crossings. The opposite could of course be true. I hope DDOT is making it's decision based on this kind of analysis.

by Lance on Jun 2, 2009 5:44 pm  

James: and how is that different from the current sitation at 15th and W?

Lance: if it has stop signs or traffic signals, by definition it's NOT a roundabout. You cite Dupont Circle, which by every definition of the term is an older-style traffic circle, not a roundabout.

by Froggie on Jun 2, 2009 5:57 pm  

Jazzy, it's a matter of semantics. Dupont Circle operated for more than a century without traffic signals. Wikipedia says most laymen in the US use the two terms interchangeably, but that roundabout (as you said) is nowadays from technical folks reserved for 'without signals'. That said, I'd like to see Dupont Circle become a roundabout.

by Lance on Jun 2, 2009 6:07 pm  

erratum. I meant to address that last post to Froggie

by Lance on Jun 2, 2009 6:30 pm  

Those signals at Dupont Circle are pet peeve, always hard to cross, always confusing tourists.

Other than Mass Ave, all the intersections might very well work better with a big fat "yield to pedestrians" sign.

by цarьchitect on Jun 2, 2009 6:34 pm  

For Dupont Circle to truly become a roundabout, the radius would have to be tightened up a bit. There are more engineering standards separating roundabouts from traffic circles than simply one never has traffic signals...

by Froggie on Jun 2, 2009 6:51 pm  

"For Dupont Circle to truly become a roundabout, the radius would have to be tightened up a bit. There are more engineering standards separating roundabouts from traffic circles than simply one never has traffic signals..."

In Paris, l'Etoile which surrounds the Arc de Triomphe is far far larger than Dupont Circle ... and it functions quite well as a round about. Granted, pedestrians have underground passages to take them to the park in the middle of the circle, but given that there are 10 lanes of traffic going around it, that's reasonable ...

by Lance on Jun 2, 2009 10:40 pm  

Again, Lance, what you cited is a traffic circle, not a roundabout. As I've already mentioned, there are fundamental differences between the two, not the least of which is the radius of the circle.

by Froggie on Jun 3, 2009 6:43 am  

I asked a friend at DDOT about a roundabout at that location and he replied that there wasn't sufficient space.

Not sure I believe that.

My POV is that the problem starts with traffic on 15th Street moving too fast. Evening rush is particularly bad, with drivers using 15th as an alternative to 16th. So you have drivers who only care about getting out of town as quickly as possible, approaching what is a very confusing intersection.

For pedestrians, there are 8 crosswalks at that intersection, and for only a few of them is it obvious where the threat is coming from.

When DDOT gets this intersection fixed, they can tackle the disaster at 16th/Columbia/Mt. Pleasant St. It is a miracle we're not losing one pedestrian per day at that location.

by Mark on Jun 3, 2009 11:36 am  

This is exactly why 15th should be converted to a two-way (notwithstanding the fact that DDOT's temporary fix is very weak). Cars come speeding up from the south here on the current urban freeway of 15th street. Unfortunately, DDOT has wimped out on that one too.

http://www.thewashcycle.com/2009/02/ddot-going-with-5th-alternative-for-15th-street.html

Someone died here! If there was a hole in the ground that we know people could fall into and die, would we cover it? Probably, but for some reason the seriousness of this type of situation seems to be lost.

by neb on Jun 3, 2009 1:30 pm  

A single lane modern roundabout needs about 90 feet of diameter as a minimum, not counting sidewalks, and can handle up to 20,000 vehicles per day. Mini-roundabouts built to US standards, not UK, are smaller. The typical operational speeds are designed for 15-20 mph maximum. The delay per vehicle would be about 2-5 seconds on average compared to a singal where the delay averages 12+ seconds. For pedestrians, 20-mph speeds means in a crash there is an 85% chance of no injury. Modern roundabouts are always yield control on entry for motorists with the circular roadway having the right of way. They usually have islands at the entries to help pedestrians cross and they are designd to always operate at 20 mph or less.

by ScottB on Jun 3, 2009 2:47 pm  

Mark, I think you're spot on. There seems to be a fetish in the land of the free for all things European, even when they're bally stupid ideas (inevitably dreamt up by traffic engineers) that cause no end of community severance. A two-way 15th St makes a heck of a lot of sense. An alternative would be making the block immediately south of U southbound only, although it's not quite as good for ultra-local traffic.

And even traffic circles are pretty bad for pedestrians (even if they have fewer advantages for vehicles). Try walking straight from the Avenue des Champs Elysées to the Avenue de la Grande Armée: it's a royal PITA. And it's ultimately why the public realm on the AdlGA is significantly worse.

by James D on Jun 3, 2009 3:59 pm  

Mark/Scott: from my eye, there's roughly 100ft (also not counting sidewalks) of width available at 15th and W, so a single-lane roundabout would definately fit. And looking at traffic counts, a roundabout shouldn't be a problem for that either.

by Froggie on Jun 4, 2009 6:48 am  

I agree with James D. Roundabouts make for dicier walking and it takes more time to get around them. The shortest distance between two points is a straight line. There's got to be another way to prevent drivers from killing pedestrians than ruining the cityscape.

by Jazzy on Jun 4, 2009 7:19 am  

A 1-1.5 lane roundabout with a signalized pedestrian mode shouldn't have any of the safety/throughput downsides associated with strict traffic control. A cycle with 3 minutes of all-direction traffic, ten seconds of all-red, and 50 seconds of pedestrian traffic seems like it wouldn't hurt navigability too much, considering the number of lights that one currently has to wait for.

by Squalish on Jun 4, 2009 7:25 am  

Having just crossed W at 15th & yelled at an aggressive motorist this morning, I suggest the following:

#1. Most importantly: All right turns onto W Street should force speeds down to 10 mph – install a 10’ curb radius. Test designs that give fire trucks access while slowing all other traffic. Remember that far more people have die or are severely injured from traffic than structure fires.

2. Close slip lane on 15th that channels traffic to Florida & W, move on-street parking left.

3. Add angle or perpendicular parking if more space needs to be consumed on 15th.

4. W St between 15th & 16th: Do NOT add a vehicle left turn lane. Add a striped 5’ bicycle lane or two bicycle lanes – one counter flow. Counter flow bike lane could protected flush with north curb; (move parking south) – which can then be used for joggers & walkers who are do not have an adequate sidewalk (Park service sidewalk is two bricks, gets muddy, only can accommodate one walker abreast. We could say the protected lane is for pedestrians if they don’t like a counterflow lane.

by ccort on Jun 4, 2009 9:45 am  

Jazzy: please explain how a roundabuot would [i]"ruin the cityscape"[/i]. Especially in a town that already has several older traffic circles.

by Froggie on Jun 4, 2009 10:23 am