Tag: intersection design

There are many kinds of shared space

A guy standing in the middle of the intersection

I took this photo outside the café Memory Lane in Rotterdam because the man in the white shirt was standing in the “middle” of this intersection for a couple of minutes. Before he took this position, he was walking slowly across the intersection to the opposite corner as his car. He’s a livery driver, and he appeared to be waiting for his passenger.

This intersection is raised (the sidewalk is level with the road surface), and is uncontrolled (there are no traffic signals, stop signs, or yield signs). A bicyclist or motorist can pass through this intersection without having to stop unless someone is walking, or a bike or car is coming from their right.

This junction has no crosswalks, either. And no one honks. Especially not at the man who’s in the roadway.

Because he’s not in the roadway. He’s in a street, and streets are different. Streets are places for gathering, socializing, eating, connecting, traveling, and shopping. There was plenty of space for him to stand here, and for everyone else – including other motorists who were in their cars – to go about their business.

The City of Chicago should implement filtered permeability immediately at Green Street and Milwaukee Avenue

This is not a bikeable block

The multiple threats to bicyclists, to pedestrians, and to motorists, are pervasive in the depicted scene. There is low visibility for turning motorists which in turn causes them to encroach on the right of way of other street users, including other motorists, bicyclists, and pedestrians.

This single image shows everything that is inefficient and dangerous to bicyclists and motorists about the intersection between north-south Green Street and diagonal Milwaukee Avenue in River West. Motorists should be physically blocked from entering or exiting Green Street at this point because of the danger inherent in the current intersection design. The block of Green Street south of Milwaukee Avenue is so insignificant to the driving network that no other design intervention should be implemented.

The situation depicted in this photograph demonstrates why the City should implement filtered permeability and close this entrance of the Green Street/Milwaukee Avenue intersection to motor vehicle movement. While motorists would be barred from entering or exiting Green Street here bicyclists would still have access to Green Street as part of the low-stress bicycling network of which Green Street is a part, between Milwaukee and Van Buren Street in Greektown.

I first wrote about this problematic intersection in June on Streetsblog Chicago and it remains an issue. One of the two motor vehicles ahead is blocking part of the bike lane while the second threatens to enter it. The bus on the left prevents the bicyclist in the bike lane from maneuvering around either vehicle. The photo below shows the situation from a different angle, that of the motorist wanting to turn left.

The vehicle operator on the left – a bus driver, in this case – has stopped the vehicle because they can occupy the intersection with the vehicle, or leave it open. Essentially, the bus driver has stopped to “let” the motorists on Green Street proceed across Milwaukee and further north into Green Street or turn left onto Milwaukee. Their movements would, again, put the bicyclist in danger, and put themselves and other motorists in danger because they are making nearly-blind turns into faster moving traffic.

The threats to the motorist are as limitless as the ones to the bicyclist (although the bicyclist will experience much greater injury if the threat is realized). As the motorist is paying attention to other motor vehicle traffic the bicyclist is coming down this bike lane – yep, I took the photograph – and is additionally obscured by the line of parked cars on the bicyclist’s right, and is in the shadow of the bus and the buildings. It’s like there’s a perfect storm of blind spots.

The quickest way to implement a system of filtered permeability and raise the significance and safety of the Green Street and intersecting Milwaukee Avenue blocks within the low-stress bicycling network would be to install a series of large planter boxes that prevent motorists from entering or exiting Green Street but allow bicyclists to filter through the planters.

And skip any traffic impact study. Not a single parking space will be lost or be made inaccessible with the implementation. A traffic study is not an experiment, but has practically been a foreboding document that has only ever said “things will be different”. (A good plenty of them have also suggested adding multiple $300,000 traffic signals.)

I read on Streetsblog USA recently about Pittsburgh’s new protected bike lanes:

“Instead of asking people to judge the unknown, the city’s leaders built something new and have proceded to let the public vet the idea once it’s already on the ground.”

Chicago maintains a Silver bike-friendly commenting ranking, yet my initial analysis shows that our metrics are below average among other Silver communities after which I’m led to believe we’re undeserving of the medal. Safety is a citizen’s number one concern when considering to use a bicycle for transportation and it will take an expansion of the low-stress bicycling network – currently not a priority – to deserve the current ranking or achieve anything higher.

Two bicyclists take different routes around this driver blocking the bike lane with their car

This photograph depicts a nearly identical situation but from the perspective of the motorist on Green Street approaching Milwaukee Avenue. Two bicyclists have taken two routes around the motorist blocking the bike lane with their vehicle.

Intersections are long!

There are many intersections in Chicago that are so long that, while cycling, I can enter it (by passing the stop bar) on a green light, be in it during the entire 3-second yellow phase, and exit the intersection after it’s been red for several seconds.

I don’t like this. I think it puts me at risk. We could make our intersections shorter or we could increase the length of the yellow and all-red phases. One of these intersections is Elston Avenue at Ashland Avenue. Going southbound on Elston Avenue, the distance from the west side to the east side is about 200 feet. Traveling at 14 MPH (because you didn’t have to stop, it was green when you arrived), that will take you 9.75 seconds to cross. Some people will be traveling faster but at this point you’re also riding uphill because of the railroad viaduct you just crossed under.

Traveling at 17 MPH, it will take you 8 seconds to cross – you’ll still be in the intersection when it’s red!

The 3-way street

Update June 12, 2011: Added a link to and excerpt from commentary by David Hembrow, a British blogger in the Netherlands.

How does a 3-way street work? Easy, just watch the video.

I like the term “aggressive yield” to describe the situation when a motorist does yield to pedestrians crossing the street, but in a way where they inch forward continually, slowly pushing, with a buffer or air, the people out of the way.

I really like the comment from Tuesday by Anthony Ball:

those red markers are just showing the limits of tolerable risk as established by years of system development. If the collision speeds were higher, those red circles would be far few – it’s simply a system finding its own point of stability.

If you really want to wreak havoc – try to control that system without corrective feedback (eg more rules, lights, controls, etc) and you’ll see the system kill people while it tries to find new stable relationships.

don’t forget that rules, signs, lights, etc have no direct impact on the system – they only work through the interpretation of the users.

What did David Hembrow have to say? David lives in the Netherlands and disagrees with the common sentiment that these conflicts are caused by selfish users.

I don’t see the behaviour at this junction as being about “bad habits”. What I see is simply a very badly designed junction which almost invites people to behave in the way that they do.

Dutch road junctions don’t look like and work like this – they are different for a reason: it removes the conflicts and improves safety. A long-standing theme of Dutch road design is the concept of Sustainable Safety. The concept is to remove conflict so that collisions are rare and the consequences of those which remain are relatively small. Roads are made self-explanatory so that bad behaviour is reduced and the way people behave is changed.

Reading this reminds me of the work of the students in George Aye’s class at SAIC, “Living in a Smart City.” The students attempted, through an intersection redesign, to reduce the stresses that lead to crashes.

Where are the 3-way streets in your city? Grand/Halsted/Milwaukee in Chicago comes to my mind easily. Also a lot of streets in the Loop. Oh yeah, and The Crotch, at Milwaukee/North/Damen.