Narrow roads often work better than wide ones

Author:

Philip Langdon

New Urban Network

 

During the Institute of Transportation Enginers’ annual meeting in St. Louis last week, Heather Smith, program director for the Congress for the New Urbanism, hailed the response that a CNU-ITE manual — Designing Walkable Urban Thoroughfares: A Context Sensitive Approach — has generated.

Smith says that the manual has been downloaded more than 1,500 times from the ITE website, and is being used by transportation planners, public works departments, city leaders, and community members. It’s helping them to “design better streets, mitigate traffic, spur economic growth, and act on public health concerns,” says an account posted on the CNU website.

In her dispatch about the conference, Smith also told about “several counterintuitive and overlooked points,” which were presented by John LaPlante, chief transportation planning engineer in the Chicago office of T.Y. Lin International. Those points, Smith says, were:

 

  • Designing wider roads means more time for pedestrians to cross, which in turn means more wait times for cars.
  • Designing more wait times for pedestrians means most cars will go 45 mph on major thoroughfares and stop for 2 minutes instead of going along at 30 mph with less stopping time.
  • In scenarios with narrower streets engineers can actually increase car capacity because there is less time for pedestrians to cross the street.
  • Mid-block crossings are safer for pedestrians because there is traffic coming from 2 directions instead of 4 at intersections.

 

LaPlante, Smith, and Jefferey Riegner of Whiteman, Requardt, and Associates discussed complete streets and multimodal level of service as part of a panel discussion at the conference.

How can many roads be made safer? LaPlante said that installing signal countdown timers at intersections reduces the crash rate by 25 percent. The new MUTCD manual is requiring these signals.

Smith also reports:

LaPlante pointed out that completes streets are a must and showed the benefits of designing speeds to Level of Service D. LaPlante also pointed out that we need better ways to measure non-motorized travel. He referred to TRB’s latest Highway Capacity manual (due out in September) that contains more advanced methods of analyzing pedestrian level of service. 

Another session, presented by Jim Daisa and Brain Bochner, discussed two new case studies — one on Lancaster Boulevard in Fort Worth, the other on a transit-oriented development near the Pleasant Hill Bart Station in the San Francisco Bay Area.