Congestion Is Your Friend

Almost everyone has heard about the list of the most congested places in America and how many hours are wasted by "sitting in traffic" and how bad this is for our national economy. Personal experience behind the wheel would certainly support the notion that congestion is unpleasant and a waste of time.

Congestion around Baltimore and construction to "fix" it

According to the 2015 Urban Mobility Scorecard, travel delays due to traffic congestion caused drivers to waste more than 3 billion gallons of fuel and kept travelers stuck in their cars for nearly 7 billion extra hours – 42 hours per rush-hour commuter. The total nationwide price tag: $160 billion, or $960 per commuter.
Washington, D.C. tops the list of gridlock-plagued cities, with 82 hours of delay per commuter, followed by Los Angeles (80 hours), San Francisco (78 hours), New York (74 hours), and San Jose (67 hours). (Texas A&M Transportation Institute, 2015, press release)

Yet, many people have come around to realize that "we can't build our way out of congestion" or to put it more bluntly, that building wider and bigger roads against congestion is like schnapps for fighting alcoholism.

Urban Congestion is old and not contingent on cars

But hardly anybody realizes how lopsided our definition of the term congestion is, and that consequently making congestion the singular metric for transportation policy is a core fallacy resulting in wider and wider roadways. Clearly metrics determine outcomes. As good as measuring progress is in general, we become what we measure. Metrics have inherently the possible result that instead of looking at the originally intended outcome (in this case: mobility) we focus on improving the metric. The conundrum is widely discussed in the field of education concerning the issue of testing and “teaching to the test”. In the case of transportation, the narrow metric of congestion really measures only one thing: roadway delays. Some further thought will reveal how this metric creates results that are the opposite of enlightened transportation policy.

Measuring how long drivers sit in traffic (roadway delay) leaves walkers, bicyclists, transit users but also those who may sit with the driver in the same car without consideration. They are simply not included in the equation. Also not considered in the metric is the length of commutes in miles instead of minutes, which is related to how efficiently the land is used.

Urban congestion is multi-modal: Rome

Most disturbing maybe is how delay is defined. If a train is five minutes delayed it means five minutes compared to the published schedule. What does it mean for a road trip?

The surprising answer: Delay is compared to a free-flow condition of the roadway found at the time of least traffic, i.e. at night. The result of that definition means that the biggest trip time differential between free-flow and rush hour always occur on a high volume roadways designed for high speeds that have no signals.Such roadways allow for very high speeds when they are empty, but possibly very low speeds during peak hours

Even in car-centric Baltimore, urban congestion is somewhat
multi-modal

Thus the added delay times on the Baltimore Beltway or on LA's infamous urban freeways add up to an impressive overall time loss. Trips on Charles Street in Baltimore or Route 66 in Pasadena, by contrast, are comparatively slow at night due to signals, speed limits, the urban setting. Those roads also have much lower volumes. This means they attract much less attention as a problem (and, therefore, fewer dollars) even though these streets move pedestrians, bicycles, transit, and folks doing short trips to their destination, all desirable forms of mobility when one considers the full land use and transportation picture.

But freeway congestion gets all the attention of the annual congestion reports and subsequently those roadways will likely draw the most money, perpetuate the fallacy and get us deeper into the car addition.

Bicycle congestion  Copenhagen, Denmark

In other words, where people (in theory) drive fast over long distances, congestion registers the most. Somebody who putters for a short distance along an urban street with signals and all kinds of delays at any time of the day will not register as large of a speed delta between the "ideal" night time hour and the congested peak hour. Meanwhile, the urban corridor may actually serve many more people.  Transit users, car-poolers, and folks using active transportation as their mode are not accounted for at all.

On a main street, that which looks like “vehicle delay” to a traffic engineer looks like economic activity and success to a local merchant or mayor on a main street. (Transportation for America)

The congestion reports will pull money into more freeway lanes, the isochrones will move a bit, and induce additional demand, people will move even further out, and the whole cycle starts over. One can see now how flawed the metric is and how its distortion leads to toxic policies that are akin of feeding chocolate to the diabetic.

Pedestrian congestion: Car free Sunday, Paris 

Instead of asking how much time the sum total of people need in a certain region to get from their origins to their destinations (not all trips are commute to work trips!), we simply ask how fast can people drive. Even though some engineers agree that the best trips are those that have not been taken, the metric of travel delay does not give credit for trips not taken. The metric of travel delay does not credit efficiency but instead inefficiency. Efficiency that comes from dense land use, telecommuting, or a use allocation where one can walk to work, high transit usage, or even car pooling (all forms of trips not taken) is punished in a system where freeway delays are considered the real issue and receive all the resources.

It comes as a relief, then, that the US Department of Transportation (USDOT) at long last is considering a "rule change" on the methods of congestion measurements (Although the method used by the Texas Transportation Institute (TTI) to create their infamous list is their own, it closely resembles the methods of the Federal Highway Administration (FHWA) for its Highway Performance Monitoring System (HPMS)).

Streets not just for cars: Copenhagen (Photo: K Philipsen)

Indeed, USDOT proclaims that it is moving towards measuring "system performance", truly a laudable goal.  But getting to metrics that measure system performance is a long and congested route in itself. The proposed rule change for congestion is the last in a trilogy of rule changes proposed by the FHWA. The rules are supposed to be finalized in early 2017, which appears unlikely in the face of changing administrations. 

States and metro areas will still be making the bulk of the decisions. Yet through this rule and other guidance, USDOT can absolutely usher in a new paradigm by steering states and metro areas to a more holistic approach for measuring traffic congestion that counts all people in a community by counting all modes of transportation. (Transportation for America)

The problem is, the proposed rules, albeit a bit more differentiated than the old rules (reliability plays a big role, i.e. how large are the fluctuations in congestion?), they still stick with roadway delay as a key measure, even though FHWA admits itself that that metric isn't all its cracked up to be:

As with delay metrics, FHWA acknowledges that travel time indices do not capture system attributes in terms of shorter trips or better access to destinations and mode options, which may occur at the expense of greater delay.

FHWA provides as an excuse for maintaining travel delay as a key tenet in a set of performance measures, that data for system performance are harder to come by than travel delay data. That may be true, but T4America does not see data scarcity as a real problem and is opening up a campaign to fight the proposed "rule change" in favor of dispensing of roadway delay as a central measure altogether.

Streets for people: New Orleans (Photo: K Philipsen)

Consider for a moment the possibility that the complete opposite of the usual assumption about congestion may be more accurate. As I like to say, consider whether "congestion is your friend." How could that be?

If building more roads leads to more demand (more and longer trips), more dispersal, less transit usage, less active transportation and a more inefficient land use allocation, then congestion would likely do the opposite. Congestion would reduce demand, it would create more efficient land use allocation, entice people to use other means to get around or avoid trips altogether. Congestion, in other words, is exactly what keeps people from moving to places where the work trip becomes too time consuming.

So if congestion is any metric at all, it is that of its effectiveness as a sprawl buster. Once sprawl is stopped, the urban qualities that everybody is looking for increase: Vital and interesting cities, in fact, can only happen when people live in the city in which they work. If that place is too big to walk or bike or take the bus, then what is needed are not wider roads but high-efficiency transit.

Transportation efficiency metrics: Vehicle miles traveled, mode split, fuel consumption and expenditure

And what about the wasted fuel, the wasted time, and the economic losses?

True, these inefficiencies are fundamentally undesirable. However, considering that attempts to alleviate these inefficiencies with more roads leads to even larger ineffectiveness, as we have seen, it is clear that trying to deal with congestion via more roads and faster trips will inevitably lead to even more waste. As proof one only has to look to Europe, where vehicle miles traveled (VMTs) are only about half of what they are in the US, transit and active modes are much more popular and, therefore, overall efficiency is higher. Many cities have congestion charges or limited access by personal vehicle to parts of the core cities which, in turn, supports the mobility of transit, goods, deliveries, and emergency vehicles by keeping unnecessary commute trips to a minimum. In addition, thriving cities and healthy landscapes less impacted by cars, trucks and vans create values (land, buildings, health, safety, etc.) that far exceed any of the losses experienced due to congestion.

Thus, congestion really can be your friend, at least if you belong to those who believe in high-quality cities and hope that the urban renaissance is more than a fleeting fling of some millenials, and in fact is an enduring and sustainable love affair that brings us livability, sustainability, resilience, and some sanity after some 70 years of insane transport policies.

Klaus Philipsen, FAIA
edited by Ben Groff, J.D.

Transportation for America on the Expectation of new federal ruling on Congestion
Federal Rule
T4America Evaluation
Methodology of the Texas A&M Institute of Transportation
The Road Less Traveled, Brookings