(This posting is another in our Brainerd/Baxter Strong Town series, which focuses on land use practices in my neighboring hometowns. In doing so, we are seeking to highlight problems with the current approach towns take to growth and development and provide real-world strategies for growing Strong Towns. If you have not read the kickoff article for this series, I would recommend it before reading this post. You can also read other posts in this series by clicking here.)
On Monday we talked about a road reconstruction project in Afton, Minnesota, and how their city finances did not account for their long-term road maintenance liabilities. Yesterday we examined two roads sections - the typical engineered street we find in most of our neighborhoods (our example was from Walker, Minnesota) and the narrower, more appropriately-sized street section we photographed in Celebration, Florida. Today we are going to take this street discussion further and show how my hometowns of Brainerd and Baxter can reduce at least one line in their budget by 43%.
Like nearly every town in America, Brainerd and Baxter have standard sections that they rely on for constructing and reconstructing their local streets. Typically these are recommended by the city engineer. Those recommendations often come from design manuals or accepted standards from other jurisdictions.
For the sake of this discussion, we are going to focus on the very low-volume end of the standards for each community. Brainerd has a standard for "Marginal Access" streets, which it indicates would be less than 300 ADT (the Average Daily Traffic amount). Baxter has what they call a "Local Street", which we believe would be in that same range. If you are visualizing this type of street in your own community you can simply picture the last street most people drive on before turning into their driveway.
For these low volume roads, the two cities have the following surface width requirements:
Brainerd: 28 feet
Baxter: 26 feet
Before we go any further, it is important to note a couple of things. First, both communities design for two lanes of traffic. This may seem intuitive since nearly all streets are designed in this way, but it is a point I do not want to gloss over. We have designed these streets so that cars can meet traveling in opposite directions. With less than 300 cars per day, we would expect to see, on average, one car travel the street every two and a half minutes (assuming all traffic happens during twelve hours of the day).
The other thing to note is that a 14-foot lane is a freeway-sized driving lane. The design speed on each of these roadways is greater than 35 MPH. These streets have the highest number of intersections and speed changes (remember, they are the last street before you turn into your driveway) and are also most likely to have kids playing in the yard, dogs running around, mail carriers, etc.... Not only can you meet another car traveling in the opposite direction, but you can do so at high speed.
So what Brainerd and Baxter are doing - like nearly every other town in America - is designing their lowest volume streets, streets that have the most potential for accidents, for high-speed travel.
What if we turn this around? What if these streets were designed not based on the notion of carrying traffic volume at efficient speeds but instead were designed for the context of the neighborhood?
One place where this is happening is in the SmartCode. The design standards in SmartCode recommend 8-foot lane widths for up to 20 mph design speed. At 9-foot lane widths, SmartCode indicates a capacity of 2,500 vehicles per day. That is more than eight times the design volume Brainerd and Baxter intend with their 13 and 14-foot lanes.
If your engineer does not trust the planners that assemble and maintain SmartCode, perhaps they could rely on the professionals that helped assemble the standards contained in the book Residential Streets. Endorsed by the American Society of Civil Engineers and the Institute of Transportation Engineers, Residential Streets recommends 9-foot lane widths for local streets.
Brainerd and Baxter could reduce their design sections for local streets from 28-feet and 26-feet wide respectively to 16-feet and, in doing so, not only save money but build streets that are safer and more pleasant to live on.
One of the first steps to building Strong Towns is understanding the financial implications of our land use decisions. Designing our neighborhood streets as if they were high-speed freeways requires 43% more surfacing than if we designed them with a neighborhood context. When organizations like the American Society of Civil Engineers and the Institute of Transportation Engineers are recommending standards that are dramatically more affordable than the ones we have adopted, why do we insist on the freeway design?
Doing so in times of plenty is wasteful and short-sighted. Doing so when the economic outlook is dire is just plain dumb.