Friday, December 5, 2014

Some Roads Should Just Go on a Diet

Bigger is better right? By and large the answer is no. Bigger is not always better when addressing roadways that run through commercial corridors.  In many places where LOA works, the challenges of a too wide street - one designed for cars but not for people or even bikes - undermines local businesses who see traffic speed by, unlikely to stop.

The problem of too wide streets is rampant throughout the nation. This issue came up recently for us...LOA is currently working on a project in Chicago where the large berth of the street was simply too cumbersome and unnecessary. And when we looked at traffic counts we found that there was actually much less traffic on a road that was clearly designed to handle much more. So, what to do with so much excess "fat"?  We suggested that roadway go on a road diet.

“Road dieting” is a term applied to “skinny-ing up” streets into leaner, more productive members of society. The ideal roadway candidate, as Burden and Lagerwey, of Walkable Communities Inc, note in "Road Diets: Losing width and gaining respect," is often a four-lane road carrying 12,000-18,000 auto trips per day. But as many of you know, road diets can be controversial in places where people think that a narrower road means more congestion - but in most cases the facts simply do not bear out.

Before and after Road Diet pictures. Image source:
Before we get to that, first back to Chicago. Our work resulted in a few key recommendations, the first included removal of a dedicated rush-hour lane (a parking lane that was converted to a travel lane only during rush hour - making it impossible for drop-in customers to stop by and therefore hurting local businesses). What we found that that although the street was perceived as a busy thoroughfare, data suggested otherwise: 13,300 Annual Average Daily Traffic (AADT) counts (between North Pulaski Road and North Kedzie Avenue) put the traffic flow as moderate to relatively low.

With low-traffic counts, we knew that the replacement of a single rush hour lane with on-street parking would not only allow customers to stop more easily - picking up food or convenience items on their way to or from work - but that it would also result would be slower speeds for motorists in general. Narrowing the flow of traffic and adding bike lanes – aka a “road diet” - would help address some of the concerns that residents and businesses have with the sometime excessive speed of motorists who pass through the area. And taking this a step further by adding a lane for bicyclists would add another transportation option  for a low-income community with very low car ownership rates.

Much safer corridor for all. Image source:
Public safety has always been a proponent of change for urban development and planning, this case is no different. A reduction in a lane or lanes, a road diet, can reduce unsafe driving, excess speeds, and serve as a street calming mechanism. Burden and Lagerwey note "crash rates and severity of conflicts with autos result in almost certain death (83% of pedestrians hit at 40 mph die)".  Four lanes of traffic are difficult to cross for pedestrians and uncomfortable/dangerous for cyclists. Furthermore, businesses that might benefit from co-location across the street from another business never accrue the benefits because for most pedestrians, they might as well be miles away.

In addition to safety, a road that has dieted sees change in commercial activity around the road. The change can increase value of existing properties and some cases costs of reconstructing roadways are repaid in as little as one year through increased sales tax or property tax revenue.

Image source:
Even high-density urban downtowns can go on diets. San Francisco, as seen in the image to the left, envisioned a downtown along Sixth Street with a more pedestrian and cycling friendly environment with continued on street parking.

In an opposite regard, a study by Thomas Welch “The Conversion of Four-Lane Undivided Urban Roadways to Three-Lane Facilities” demonstrates the problems and negative outcomes associated with increasing road sizes from a slimmer two-lane road to a wider four-lane road.  Welch notes it led to increased accidents, increased speeds, increased corridor delays, and increased injuries.  Not the results people want or expect - sometimes slimming down is the best remedy for the health of your commercial district.

If you want to read are some additional readings:

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