a major priority for the transportation engineering profession. It is no coincidence that these values were built into the transportation vocabulary.5
While civil engineering itself is one of the oldest professions, with techniques and insights dating back thousands of years, the subspecialty of traffic engineering is very young. Some of its earliest practitioners are still alive today. This was an entirely new pursuit, developed on the fly, in a period of tumultuous change.
Coming out of the Great Depression and World War II, the United States desperately needed a program that would keep the economy going. While the war had created jobs and economic output, demobilization threatened to shift the economy right back into depression. The redirection of American industry and capital from war-making into suburbanization created a kinetic growth machine that fueled a postwar boom.
We built a new version of America, one centered around the automobile, transforming an entire continent in a generation. Traffic engineers were tasked with making transportation in this newly imagined approach work. To do that, they needed to standardize nearly every component of this system so that it could be recreated, at scale and with urgency, across a vast continent. It is difficult to overstate how monumental an undertaking this was, nor how astounding their success was in accomplishing it.
In those early days, significant gain in travel speed could be achieved merely by improving driving surfaces and roadway conditions. With new highways connecting distant places, an increase in speed also meant an increase in overall mobility; people could reach more places with the same amount of time investment. Distances previously unheard of were now being routinely traveled by millions of Americans. Under these conditions, focusing on increasing speed was an easy proxy for increasing mobility.
In the decades immediately after World War II, increased mobility was driving economic growth. Whether it was families living in new housing in the suburbs, the ability of employees to switch jobs more easily, or the capacity for farmers, loggers, and miners to get their materials to distant markets, the fact that Americans could reach more places in less time provided accelerating levels of prosperity.
This notion became a self-evident truth embedded within the traffic engineering profession. Out of it sprung many beliefs that are now orthodoxy. These include the following:
Faster speeds are better than slower speeds.
Access to distant locations by automobile is more important than access to local destinations by walking or biking.
Accommodating a full range of movement for large vehicles is more important than minimizing construction costs and increasing safety for people walking.
At intersections, minimizing delay for automobile traffic is more important than minimizing delay for people walking or biking.
Economic growth is a greater priority than community wealth preservation or financial productivity.
Today, the American transportation system is fully mature. We finished building the interstate system over four decades ago. The easy mobility gains have long been tapped. We are now left almost exclusively with expensive modifications that provide comparably modest changes in travel time, a theoretical benefit that is quickly denuded by shifting traffic patterns. To the extent that it once was, designing for speed is no longer a proxy for increasing mobility.
Yet these core insights of the early profession persist. State Street was designed for speeds far in excess of what is even legal there. The entire street is built to favor commuters driving into Springfield from distant locations in the morning and departing in the opposite direction at the end of the workday, prejudicing the person who lives close to the downtown and commutes on foot in the process. This is not only dangerous, but it has also had a disastrous impact on property values within the core of the city.
The lane widths, recovery areas, and turning radii at the intersections are designed for the ease of large vehicles, even though they are infrequent, and even though this design makes State Street more dangerous for drivers at nonpeak times, and more dangerous at all times for people walking and biking. Each intersection where assistance to cross the street is provided, the burden of delay is shifted away from the driver on State Street and to the person walking, even at the hour when Sagrario Gonzalez was making her decision on where to cross.
We cannot in good conscience blame Sagrario Gonzalez for the tragedy that occurred on State Street. She was navigating a space that was, at best, indifferent to her and her children's safety. At worst, it was outright hostile. It remains that way to this day, as do most local streets in the United States.
We can be generous in our interpretation of history and thereby more understanding of how the traffic engineering profession came by its core set of values. Even so, these values must be acknowledged if only so that they can be consciously set aside in favor of a more modern and universal set of human values.
The Strong Towns Approach
Traffic engineers are a critical part of designing transportation systems, but the values of the public need to dominate decision-making. Value decisions need to be stripped out of the design process and given over to nonprofessionals, preferably elected officials and the people living within the community— those directly affected by the design.
Table 1.2 gives an example of who should make what kind of decision during a street design process.
Elected officials must be given the ability to set the values for the project. It is their responsibility, on behalf of the people they serve, to establish the automobile design speed, the number of vehicles that should be accommodated, the size of vehicle that should be considered in the design, and the degree of deference that should be shown to people walking or biking at a given intersection. These are not design decisions; they are value decisions.
We must also insist that engineers use value-free descriptions for the work they are doing. If they are proposing to widen the street, it should be called a “street widening” and not a “street improvement.” If they are cutting down all of the trees adjacent to the street, it should be called “tree removal” and not brought forth as an “enhancement.” The goal for everyone is to communicate as clearly, factually, and value-free as possible. Elected officials must insist on this.
Table 1.2 Who Makes the Decision?
| Nonprofessionals | Technical Professionals |
|---|---|
| Design Speed | Pavement Thickness |
| Design Volume | Pavement Cross Slope |
| Design Vehicle Size | Lane Width |
| Intersection Priority | Bituminous Mixture |
The burden and responsibility of making value decisions should not rest with technical professionals. Traffic engineers are incapable of representing the complexity of human experience that needs to be considered in a street design. That is especially true when industry orthodoxy is adhered to. This is not so much a statement on the engineering profession as it is an acknowledgment that city streets are the frameworks of human habitat, a complex-adaptive environment that must harmonize many competing interests.
As
