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Posted Apr 18, 2014, 4:34 PM
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Registered User
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Join Date: Aug 2002
Location: Toronto
Posts: 52,200
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Bike Lanes Don’t Cause Traffic Jams If You’re Smart About Where You Build Them
Read More: http://fivethirtyeight.com/features/...ou-build-them/
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As cities re-design streets, they’re making a concerted effort to create more bike lanes. This is happening not only in large metropolises like New York City, San Francisco and Chicago. Bike lanes are in the planning or construction phases in Louisville, Ky., Raleigh, N.C., the Buckhead neighborhood of Atlanta, Ferndale, Mich., Rutland, Vt., and Elyria, Ohio.
- New bike lanes certainly make life better for cyclists, but how do they affect drivers? This question is hotly debated, especially when a new bike lane replaces a lane used by vehicular traffic. It seems that unless a ton of people start commuting by bicycle, giving away a lane would cause increased car traffic. But is this really the case?
- We tried to answer this question by looking at Minneapolis, which Bicycling magazine has recognized for several years as the best city for biking in the U.S.1 (Yes, this is the same Minneapolis where the average high temperature in the winter is below freezing. These cyclists are dedicated.) True to this ranking, Minneapolis funded the construction of 45 miles of bike lanes in 2010 and 2011. To test a bike lane’s effect on congestion, we looked at the 10 road segments that gained a bike lane during this construction at the cost of a driving lane.
- Minneapolis doesn’t report traffic data broken down by day and time. It’s difficult to find this data for any city. What Minneapolis does report is the Average Annual Daily Traffic (AADT), a measure of the number of cars and commercial vehicles traveling on a road in a typical day. A city may collect this information continuously throughout the year, or over a few days using portable sensors. If you’ve ever driven over a thin black pneumatic tube lying across a road, then congratulations — you’ve probably been counted in the AADT.
- Minneapolis measures AADT on the same roads every few years, so we have data from before the bike lane installation (in 2008 or 2009, depending on the road) and after the installation (in 2012). We found that each road seemed to have about the same traffic volume after its bike lane was installed. Running a statistical test across all 10 roads confirmed that there was no difference in AADT before and after the installation of the bike lanes.2 Now, you may be saying, “Hold up! If you have the same number of cars traveling down a road with one fewer lane, won’t there be a lot more congestion?” A good point, and one that requires us to look beyond traffic volume.
- To estimate congestion during rush hour, we can convert AADT to an estimate of the number of cars traveling in the busiest direction during peak travel time.3 Dividing this by each road’s capacity4 gives us what traffic engineers call the volume-to-capacity ratio, or V/C ratio. This metric tells us how “full” each road is. As the V/C ratio approaches 1, the amount of congestion increases. At V/C ratios between 0.5 and 0.75 you have mild to moderate congestion, where traffic is still moving smoothly but you might notice that it’s a bit harder to move from one lane to another.5 At V/C ratios between 0.75 and 0.9 you experience heavy congestion and the effect on your commute is greater. Here, traffic starts to slow down and minor incidents can cause jams. Severe congestion occurs at V/C ratios above 0.9, where the road is almost at capacity and there are no gaps to switch lanes. The V/C ratio for our 10 streets in Minneapolis can be seen in the following chart.
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DC Inspires Bike Lane Envy With Curb-Protected Cycling
Read More: http://streetsblog.net/2014/04/15/dc...ected-cycling/
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Here’s a good sign that protected bike lanes are here to stay in American cities: Cities are increasingly trading plastic bollards for concrete curbs, making the lanes a more permanent feature of the landscape. As I reported for People for Bikes last year, Chicago, Austin, Seattle, New York and Portland have all either installed or plan to install curb-protected bike lanes. The latest city to join this elite group is Washington, DC.
Cirrus at Greater Greater Washington explains the new bike lanes coming to M Street and 1st Street in the nation’s capital:
Their designs are a step up from previous DC cycletracks, since they each include spots — though on M, a very brief spot — where a full concrete curb separates bikes from cars. The 1st Street NE cycletrack connects the Metropolitan Branch Trail to Union Station and downtown DC. DDOT installed its curb last week, from K Street to M Street. Crews are still working on striping and signals, but the project is close to opening.
The M Street cycletrack is longer than 1st Street’s overall, but the portion with a curb is shorter. It’s less than one block, where the cycletrack briefly curves onto Rhode Island Avenue in order to approach Connecticut Avenue more safely. Officials say the M Street cycletrack is a week or two from opening. Typically DDOT uses plastic bollards instead of curbs. The bollards are less expensive, easier to install, and can be removed occasionally to perform street maintenance. But they’re less attractive and less significant as a physical barrier, compared to a curb.
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Could IDOT Bike Plan Represent a Turning Point for the Car-Centric Agency?
Read More: http://chi.streetsblog.org/2014/04/1...entric-agency/
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The Illinois Department of Transportation has a long history of promoting driving before all other modes. However, its new Illinois Bike Transportation Plan, released this morning at the Illinois Bike Summit in Champaign, may represent a new direction for the department.
In recent years, IDOT has pushed wasteful, destructive highway projects like the Circle Interchange Expansion and the Illiana Tollway, and it recently released a “Purpose and Need” statement for the North Lake Shore Drive rehab that was written largely from a windshield perspective.
When the department launched the public input process for the state bike plan last summer, it was still prohibiting Chicago from installing protected bike lanes on state roads within the city, apparently for reasons that had nothing to do with safety. It seemed ironic that IDOT was seeking input on strategies for improving bike safety when its own policy undermined it.
In October, at a memorial for Robert “Bobby” Cann, a cyclist who was killed by a motorist on Clybourn, a state road, it was announced that IDOT was lifting the PBL ban. The agency is currently working with the Chicago Department of Transportation to design protected bike lanes on Clybourn, possibly shielded by concrete curbs, on an experimental basis.
This morning, the Active Transportation Alliance heralded the release of the bike plan, which calls for improvements to state road design and more funding for bike safety projects, as a sign of IDOT’s growing commitment to improving conditions for non-motorized transportation. “This is not an easy task given IDOT’s historically car-centric perspective that has de-prioritized biking and walking,” the Active Trans release said.
“With the adoption of its Complete Streets policy in 2007, its plans to pilot-test protected bike lanes on state routes, and now the state bike plan, I think it’s fair to say IDOT is turning the corner, so to speak, toward a multi-modal approach that provides a range of transportation options for Illinois residents,” said Active Trans director Ron Burke in a statement.
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Website: http://www.bikelib.org/other-advocac...s-bike-summit/
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