Confessions of a Recovering Engineer. Charles L. Marohn, Jr.
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 I will demonstrate in upcoming chapters, if we align the design approach with the values of the community, we can reduce death, create places of greater prosperity, spend less money on transportation, and get a better functioning system. We can do all of this, but only if we address the underlying values of the design process. To build a strong and prosperous community, local leaders must assert their community's values and see them reflected in the transportation system.
State Street in Springfield is designed with the wrong values. Its purpose is to move a high volume of automobiles at speeds much higher than what is safe for that area. Instead, it should be redesigned to prioritize safety. The value decisions for State Street were made without presenting the value options to elected officials, let alone the community at large. Both almost certainly have different priorities.
More information on State Street in Springfield, including maps, photos, and supporting documentation, is available at www.confessions.engineer.
Notes
1 1. This will be discussed in greater detail in Chapter 7, “Intersections and Traffic Flow.”
2 2. There is way more to a street than moving traffic. We'll discuss this more in Chapter 5, “Great Streets.”
3 3. See the Introduction for more on this video.
4 4. More on this in Chapter 5.
5 5. ITE Journal, January 2017. https://tooledesign.com/wp-content/uploads/2019/02/ite_language_reform-by-ian-lockwood-pdf.pdf
2 The Difference Between a Road and a Street
The following words and phrases, when used in this Manual, shall have the following meanings: 225. Street —