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!


  1. steven says:

    In relation to “financial advisors role” we should possibly move away from a role that increases responsibility 10 fold and increases the opportunity for court appearances. Our use of models does bare a similarity to financial modellers but in moving into the role of “financial advisors” will our Macro Micro and Meso models come with an appropriate level risk advice? ie “this is what MAY occur unless any one of a plethora of parameters changes and the exact opposite scenario occurs” or do we deliver a full array of multiple option scenarios?
    The finance world used a model called Value at Risk (VAR) as a tool to calculate the potential risk in downside movements, this tool was based on recent patterns only, as such held no overtly negative scenarios were included, people forgot it was only a model and…… Our industry is bereft with optimism bias in models, presently we try hard to alleviate our exposure to future legal scenarios where we can and Im not sure I wish to take the responsibilities of the Financial Advisor.

  2. Jeff Riegner says:

    Steven, thanks for your comment. I’m certainly familiar with investment-grade forecasting and the additional risk it entails. Perhaps there is a better term than “financial advisor,” but the concept remains the same: transportation engineers and others with responsibility for planning and designing infrastructure need tools that will help them more broadly understand their role as stewards of public funds and make good decisions accordingly.

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