MBA: Traffic Calming

Tuesday, April 5, 2011

What’s the most effective way to make city streets safer? As Chicago Alderman Mary Ann Smith told Streetfilms, “Signs don’t do the job, even having police officers on the corner does not do the job.” To prevent traffic injuries and deaths, you need to change how the street functions and make it feel slower for drivers. You need traffic calming.

Traffic calming takes many forms and can describe any measure taken to reduce traffic speeds, improve safety, and make using the street a better overall experience. The most effective traffic calming measures are those that influence drivers to “behave in a civilized manner,” as Smith put it.

Changes like curb extensions, neck-downs, and bike lanes are all traffic calmers that save lives by sending the signal for drivers to slow down. In this Streetfilm we highlight some exemplary traffic calming projects from cities across the country.

Streetfilms would like to thank The Fund for the Environment & Urban Life for making this series possible.

http://dannyman.toldme.com/ Daniel Howard

The Bike Box has the reverse effect of curb daylighting, no? The car has to sit further back, making it less visible to pedestrians . . . we don't have these where I live, but it sounds like it might be nice for us bicyclists . . .

-danny
Andrew Besold

Just came back from Germany and even though I've been there over a dozen times, I'm still amazed at how narrow the road widths are there. There are roads that are a mere 16 feet wide (curb to curb) with parking on one side that still are wide enough for a large bus to pass through (I was on the bus). Reminds me quite bluntly how grotesquely bloated the typical American roadway is. Multi-lane roadways are almost unheard of and are reserved for the largest urban environments and the Autobahn, PERIOD!
http://www.joancharmant.com/openid/ jobigoud

We have bike boxes in France. The feeling of catching up the whole row of cars and then stopping right before the first one, in your dedicated spot, is great

Begining this year, they also allow cyclists to go counter way in one-way streets that are situated in 30Km/h areas.

Another trick I've seen is the odd removing of the center line mark. (leaving a single wide lane for both ways, but adding two bike lanes on the sides)
With the missing line, when there is only one car, it leaves you more space if you are cycling on the side.
When there is two cars crossing, they tend to go slower because they feel the risk is higher, and they need to cross the bike lane.

Check "chaucidou" on google images.
http://profiles.google.com/toddedelman1 Todd Edelman

Bike boxes are only/mostly at signaled intersections, where the pedestrian only goes on the green. Crosswalks at intersections (and not) with no stop sign etc/automatic temporary pedestrian priority need curb daylighting.
http://profiles.google.com/toddedelman1 Todd Edelman

Andrew, where in Germany are there are no multi-lane roadways? Lots of medium-sized towns have them, at least in a few locations. The big cities have lots of them and they are really horrible (not just here in Berlin)... but - true - almost all the traffic goes on these due to the 30kph zones and (sometimes) traffic calming.
http://profiles.google.com/toddedelman1 Todd Edelman

Nice job! Only obvious thing missing was some hard numbers in examples (e.g. 22% fewer crashes, or people actually noticing details whilst driving... or are these in the curriculum?). Great that there were only USA examples but wondering if there are any of legal contraflow -- this also slows traffic a lot and decreasing route length for cyclists, especially on shorter journeys (due to proportionality).
Kagi

Can anyone point me to the source of the statistic at 00:55, "streets that have bike lanes on them reduce [killed or] significant crashes by up to 45%"? Thanks!
Andrew Besold

Todd,

Yeah they are around as you well know but they are rare. The only one that I can think of that is not an Autobahn or in a major city is the ring road around my mom's hometown of Bad Kissingen and even there the left lane often turns into a left turn only.

Here in the US we seem to build multi-lane roads through residential neighborhoods almost as a matter of course even when the traffic volume doesn't warrant it. Then we are somehow surprised when speeding is rampant and crashes and deaths happen. But somehow we only see these deaths as "unavoidable ACCIDENTS".
Bob Davis

I have an issue with the term "traffic calming"--it seems to be a euphemism for "automobile driver restricting". One can imagine a driver who's just come back from a long vacation, driving down the street he normally used as a "shortcut" and finding it's been reconfigured to "encourage" slower driving (or taking an alternate route) He'd probably be anything but "calm" when he's late for worl
A. Nony Mouse

My grandparents lived in a poor neighborhood in Salford UK. The total width of their street was less than 20 feet and people still drove down it like maniacs. The Council installed alternating curb bulb-outs to create a chicane, but drivers took that as a challenge. There was nothing like the late night sounds of a 1.3 litre engine being wrung out for all it's worth and the shriek of tyres as someone threaded their Fiesta through the chicane at 40 mph.
Magdalena Morel

Do you have this video with spanish subtitles, by any chance? It would be great to show it more massively here in Chile
Cheers!
Safe Driver

I don't like "traffic calming" in most cases. The example Chicago Alderman Smith cites on Marine Drive was unnecessary. I live right next to the Drive and never thought the traffic was bad before the bumpouts and extra stop signs were installed. To justify the "traffic calming" they said 800 cars drove on Marine Drive every day. That works out to an average of 33 cars per hour each day, about one car every 35 seconds. The actual interval between cars is much greater, since sometimes cars come by three or four at a time. It wasn't a problem to cross the street to get to the park. I don't know that any traffic/pedestrian accidents on Marine Dr. were cited for the project. I don't mind the bumpouts too much, except that the City doesn't maintain them, the homeowners next to them are responsible for plantings and cleanup, which many don't bother in some neighborhoods. The beautiful Marine Dr. example in the video is next to million-dollar homes that can afford nice expensive landscaping.

When they also add unnecessary stop signs and speed bumps, and purposely uncoordinate the traffic lights to force you to stop at every one, it decreases gas mileage, increases pollution, and causes more wear and tear on the cars compared to a steady speed of 25 mph, which I feel is a safe speed. I agree some drivers drive like maniacs, but "traffic calming" doesn't deter them. As one commenter said, these obstacles only encourages drivers to to drive around them as a slalom as quickly as they can.
http://www.signsnowmillcreek.com/home/construction-signage/traffic-signs.html Traffic Signs and Road Signs

Some of the ideas may work in some instances, but the US highway infrastructure is so large that most situations do not seem practical to install traffic calming initiatives.
http://thegreatermarin.wordpress.com/ OctaviusIII

Don't seem, but sometimes are. At Raleigh's Capital Boulevard there are 8-11 lanes of traffic plus a median, and that's a fabulous blank canvas to paint as much as center-running bus lanes/street car and a cycle track, along with bulb-outs, street parking and sidewalks where there are none. You can bring it down to 4 lanes with traffic calming initiatives alone, but then you're into road-dieting.

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