How to add bike lanes and not lose car capacity

How road diets work

As cities across the US build bike lanes, their decisions are often seen as a move to give space to bikes at the expense of cars. But data tells us this isn’t always true: In New York City, for instance, bike lanes have actually shortened cars’ travel times on several streets, while simultaneously encouraging people to bike and making it safer due to road diests. (Vox.) This article continues to say road diets can take several forms, but the basic idea is that by removing traffic lanes, cities can free up space for bike lanes and reduce the frequency of crashes. Narrowing lanes from 12 feet to 10, meanwhile, makes drivers less likely to speed, and in doing so has also been shown to cut down on crashes that involve drivers, cyclists, and pedestrians.

Watch this quick, informative two-minute video to learn more.

Why Not Build More Roads?

The traffic on Rockville Pike is only getting worse.  Just yesterday, reported that our county’s second most congested intersection is where the Pike crosses Nicholson Lane (click here for that piece).

The White Flint Sector Plan includes a multi-pronged approach to improving our traffic, including building an actual street grid to diffuse it and beefing up transit options like Bus Rapid Transit.  But, I’m often asked “why not build more roads?”

The shortest answer to this question is that, aside from roads being incredibly expensive, “if you build it, they will come.”  What do I mean by that?  Wired Magazine has taken an in-depth look at this very concept, called induced demand:

[I]f there’s anything that traffic engineers have discovered in the last few decades it’s that you can’t build your way out of congestion. It’s the roads themselves that cause traffic.

The concept is called induced demand, which is economist-speak for when increasing the supply of something (like roads) makes people want that thing even more. Though some traffic engineers made note of this phenomenon at least as early as the 1960s, it is only in recent years that social scientists have collected enough data to show how this happens pretty much every time we build new roads. These findings imply that the ways we traditionally go about trying to mitigate jams are essentially fruitless, and that we’d all be spending a lot less time in traffic if we could just be a little more rational.

Read the full piece by Adam Mann, which includes more of the “why’s” and “what now’s” by clicking here.

“Road Diets” in NYC

As Mayor Bill De Blasio begins his role as Mayor of New York City, people are now examining all the changes the last mayor, Mayor Michael Bloomberg, brought to the city.

Bloomberg and his staff succeeding in changing the built environment of New York City to better the safety and well-being of its residents. His team, including former Transportation Commissioner Janette Sadik-Khan, were able to change the infrastructure of many roads and streets around the city to help pedestrians and bikers feel welcomed in their city. These changes, often called “road diets”, “shaved off excess space,” providing pedestrian-friendly spaces to once unsafe, car-centric streets. Branden Klayko provided before and after pictures of 25 areas throughout the city that show these road diets and pedestrian plazas.

Check out these amazing before and after pictures! The changes shown in these pictures are truly aspiring for us here in White Flint.