The rising gas prices are forcing everybody to take a second look at how they commute. Now WalkScore is helping people do this. They recently released a report of the most transit-friendly cities in the United States.
Cities were graded on how commuter-friendly they are, not just by ranking the quantity of transit available but also how convenient it is to citizens. Walkscore calculated the Transit Score of over 1 million locations in the largest 25 cities and used a combination of algorithms and heat maps to come up with the ranking.
These rankings will help people who are looking for a new home to pick a city with good transit systems.
The scores will also help city officials figure out which transit lines are weak in their cities so they can make improvements.
The ranking process involved two steps and a rather sophisticated methodology. First, they calculated the raw transit score and determined the value of all the nearby routes.
The value of a route is defined as the service level (frequency per week) multiplied by the mode weight (heavy/light rail is weighted 2X, ferry/cable car/other are 1.5X, and bus is 1X) multiplied by a distance penalty. The distance penalty calculates the distance to the nearest stop on a route and then uses the same distance decay function as the Walk Score algorithm.
The next step was to change this raw data into a normalized score on the scale of 0 to 100.
The amount of transit infrastructure can vary by several orders of magnitude when you compare big cities with small towns. A bus stop in a small town might see three trips a day, whereas on in downtown Manhattan might see tens of thousands. That makes it difficult to compare apples to apples. WalkScore’s methodology takes into account not only the volume of transit, but how useful it is. Says WalkScore, “the added utility of one additional bus in a small town may exceed the addition of 10 new routes in downtown Manhattan.”
Finally to normalize from 0 to 100, they had to pick a “perfect score location.” To do this, they averaged the Transit Score of the center of a five US cities for which they had full transit data. These cities were San Francisco, Chicago, Boston, Portland, and Washington DC and they were used to canonize the final data.
Image credits: joeywan, Flickr; WalkScore ©/ Screen Captures. Top – Ranking of 25 American Cities. Bottom – What the scores indicate.