Archive for January 2014

Rethinking the Goals of Transportation

Engineers have always been adept problem solvers. As is probably true for most of us, when I was in school and early in my career learning the transportation profession, I was usually asked to solve two primary types of problems. The first was safety, generally measured by rate of crashes (or fatalities, or injuries). The second was capacity, measured by delay, travel time, or some other objective measure. Those two problems, while simply defined, have been sufficiently challenging to engage the transportation profession for decades. As a result, we have developed an extraordinary set of tools and techniques to address those problems.

But now we find an expanding list of problems we are called to solve. Comfort-based quality of service metrics are now standard practice for transit (in the Transit Capacity and Quality of Service Manual) and for pedestrian and bicycle travel (in the Highway Capacity Manual). Transportation problems are societal as well, as referenced by ITE’s Sustainability Task Force and recently-launched public health collaboration.

Let me give you an example from my hometown. I recently served as the chair of the Newark Bicycle Committee in Delaware. We have two goals: reducing the bicycle crash rate and increasing the percentage of trips taken by bicycle. The first goal, of course, is at the traditional heart of the transportation engineering profession. I would argue that the second is also important, though it is not as easy to measure. The benefits of increasing bicycle mode share are increased economic activity, improved public health, better air quality, and the like – measures that take place over years or decades and are very difficult to attribute specifically to bicycling. Yet studies exist that correlate increased bicycle mode share with each of these benefits.

So let’s say, as engineers, that our task is to evaluate placement of a cycle track on a downtown street. I won’t use this post to debate the merits of separated bikeways, but let’s just say the profession is not universally convinced that they increase safety. However, it is also well known that more people bicycle in cycle tracks than in non-separated bike lanes or mixed traffic lanes. Even if the bicyclists are not actually safer, they feel safer. If we limit our measures of effectiveness to safety and capacity, our recommendation whether to install the cycle track will likely be different than if we measure a broad range of parameters.

In conclusion, I’d like to share something I heard this week at the TRB Annual Meeting. A colleague said, “We aren’t traffic engineers any more. We are financial advisors for the investment of public funds.” With that in mind, how can transportation professionals bring our analytical skills to bear to measure a wide range of metrics and then make the right choice? Let me know your thoughts!

Street Design Lessons from the Big Apple

As the Bloomberg administration completes its term in New York City, it’s a good time to reflect on the remarkable changes that have taken place over the last several years. Under outgoing Transportation Commissioner Janette Sadik-Khan, New York has undertaken nothing short of a renaissance in not only how its streets function, but how transportation is perceived by residents and visitors alike.

Recently the New York City Department of Transportation published “Making Safer Streets,” a synopsis of lessons learned as many of the city’s streets were reinvented. Although New York has many unique characteristics as compared to America’s smaller cities and towns, some of these lessons apply across the country. Here are a few points that resonated with me as being especially appropriate to the places where I’ve worked, large and small alike.

Data drives decisions. It’s one thing to estimate the safety (or other) benefits of transportation improvements. It’s another thing entirely to track those benefits in great detail to justify to policymakers that those improvements are sound investments. During the last seven years NYCDOT has taken great pains to perform before-and-after studies of each of its street design innovations to see what worked and what didn’t.

Complete streets are safer for everyone, including drivers. Some communities see significant focus on walking and bicycling as a “war on cars.” This is especially true if those projects involve reducing motor vehicle capacity or touching the proverbial third rail of urban street design, on-street parking. Data from NYCDOT show that’s simply not the case from a safety perspective.

The fundamental characteristic of the successful projects is that they create the opportunity for drivers, pedestrians, and cyclists to move through the street network simply and easily, minimizing the unexpected, the confusing, and the potential for surprises.

Return to first principles. As transportation professionals, we often rely on toolboxes of safety countermeasures to fix typical problems. Sometimes it’s good for us to re-examine what we learned in school or early in our careers: why those countermeasures are effective. The NYCDOT report offers five core concepts that have resulted in the most significant safety improvements. Quoting from the document:

  1. Make the street easy to use by accommodating desire lines and minimizing the complexity of driving, walking, and biking, thus reducing crash risk by providing a direct, simple way to move through the street network.
  2. Create safety in numbers, which makes vulnerable street users such as pedestrians and cyclists more visible. The same design principle, applied to arterial streets when traffic is light, reduces the opportunity for excessive speeds.
  3. Make the invisible visible by putting users where they can see each other.
  4. Choose quality over quantity so that roadway and intersection geometries serve the first three design principles.
  5. Look beyond the (immediate) problem by expanding the focus area if solutions at a particular location can’t be addressed in isolation.

Using these principles in concert with robust community collaboration, any place can make its streets safer and more desirable for their users.

Where have you seen any of these principles work well in your community? And where are problem areas where they might make a difference?  Let us know in the comments!


FHWA’s Bicycle Signal Interim Approval: What It Means for Practitioners

Yesterday the Federal Highway Administration published its December 24, 2013 Interim Approval (IA-16) for the use of bicycle signal faces. This development, which happened in large part due to significant efforts by the National Association of City Transportation Officials (NACTO) and the National Committee on Uniform Traffic Control Devices (NCUTCD), provides an important new tool for transportation planners and engineers to provide better bicycle facilities.

Bicycle signals have been used in Europe for many years. They provide guidance for bicyclists in many circumstances where general traffic signals or pedestrian signals might create confusion or result in conflicting crossing movements. This is especially apparent in circumstances such as cycle tracks, where motor vehicle traffic turning from the street parallel to the cycle track might conflict with bicycles. The tool is also useful where trails cross streets, as it may not be clear whether a pedestrian signal applies to bicyclists. Furthermore, bicyclists generally need far shorter clearance times to cross streets, so activating a bicycle signal (preferably with passive detection rather than a pushbutton) may reduce delays to motorists in certain circumstances.

What does the new Interim Approval mean for practitioners? Well, the NACTO Urban Bikeway Design Guide already provides recommendations for installation of bicycle signals and detection. The Interim Approval now allows jurisdictions to use bicycle signals on projects receiving Federal funds or requiring FHWA approval, without the need for time-consuming experimentation procedures.

However, there are some important distinctions between the FHWA Interim Approval and the NACTO Guide. First, IA-16 requires the use of a Bicycle SIGNAL (R10-10b) sign adjacent to all bicycle signal heads. This is a suggestion in the NACTO Guide. This makes sense in situations where parallel motor vehicle traffic may have a clear view of the bicycle signal, but is unnecessarily restrictive where driver confusion is not likely. Moreover, bicycle signals are expressly prohibited at pedestrian hybrid beacon, a location where they could play an important role. Bicyclists can cross at PHBs much faster than pedestrians, so bicycle signals combined with bicycle-specific detection could result in more efficient operation for all modes. This exclusion is disappointing, and hopefully additional research will result in approval for bicycle signals at PHBs as well.

It will be interesting to see how the Interim Approval will affect the pace at which jurisdictions install bicycle signals. Do you have experience with the efficiency and safety of bicycle signals, either as a designer or as a cyclist? If so, let us know in the comments!

[Photo source: City of Alexandria, VA. This bicycle signal, on the Mt. Vernon Trail, was installed under FHWA experimental approval.]