How Traffic Engineers Can Finally Tame Stroads

*Washington Street (Highway 210) in Brainerd, MN. (Source: Google Maps.)*

The engineers analyzing a stroad in Strong Towns President Charles Marohn’s hometown of Brainerd, Minnesota, are having a hard time seeing past speed as the number one priority for its redesign.

Marohn and others felt they’d made progress convincing Minnesota Department of Transportation designers that the stroad known as Washington Street (Highway 210) needed taming. Engineers responded they have nothing against beautification or people’s preferences to walk or bike, but their duty as engineers is to ensure that 30,000 vehicles per day do not experience significant slowdowns.

Frustrated, Marohn posed the question of why traffic engineers are so bent on accepting massive negative side effects to avoid minor reductions in travel time.

I am a traffic engineer. I know why my colleagues are fixated on travel time. Our tools and paradigms tell us we’re doing something good when we design stroads. Thus, we pat ourselves on the back while inadvertently messing up the world. In our minds, we’re helping a lot of people get from A to B as quickly as possible, and what’s wrong with that? We’re also helping people move quickly in what we believe is an affordable and safe manner. These are exactly the four priorities described in Marohn’s article: Speed, Volume, Safety, and Cost—in that order.

Can’t Afford to Install Amenities? You Can’t Afford Not To!

An optional fifth priority is “amenities,” that is, upgrades to alternative modes and aesthetics. Engineers tend to believe such investments are a waste in locations where so few will use them. Street trees? People die when they hit trees…if going fast. Since fast is non-negotiable, never allow trees near cars! Engineers realize the community is trying to change the environment, and politics will force them to throw a few bones that way. But they’re not confident the community’s vision is possible, so they say things like such amenities are beyond our budget. The lackluster result creates a self-fulfilling prophecy, where land uses are always on life support.

Toward the end of this article, I propose a hypothetical design that might give the community what they want, and also give engineers much of what they want. I also make a case that any extra costs inherent in my design will be made back in the money saved elsewhere. But first, so non-engineers can see inside the process, here are some keys to how I used to see the world, how I remain sympathetic to fellow engineers who still see things that way, and how I see things now. Of course, much detailed discussion of the pros and cons of these perspectives are in Marohn’s new book, Confessions of a Recovering Engineer.

How Do Traffic Engineers Calculate Lost Value from Lost Speed

The side effects of high-speed stroads include induced demand, suburban sprawl, health consequences, greyfield degradation, the segregation of education and housing, greenhouse gas emissions, unnecessary carnage, and unsustainable spending. Why are these negatives overlooked? Partly because they are hard to recognize. It is also hard to compute reasonable estimates for these side effects, even after recognition.

Yes, traffic calming and livable streets address the side effects of speed, but engineers would need a deep exploration of adjacent disciplines to not only see the benefits, but also account for them fairly. Most are still near the beginning of that journey of discovery, so sadly, that usually means the stroad wins.

After all, engineers can prove, to the third decimal, all the negative impacts of speed reduction. Is an extra minute of drive time a good trade for a safer, livable, vibrant community asset? You might think so, but here’s how engineers see it:

30,000 vehicles x 1.3 people/vehicle = 39,000 people, each losing a minute.
39,000 divided by 60 min/hr = 650 lost person-hours per day.
650 x 365 = approximately 240,000 lost person-hours per year.

Translating to something more understandable:

240,000 / 24 / 365 = 27 person-years of lost time annually.
Federal value of time = $21/hr (commercial + general estimate for Highway 210).
$21 x 240,000 hours = $5,000,000 per year

If 39,000 people each lose a minute, this aggregates to 27 person-years of time lost each year. If we value that lost time at $21 per hour, this 27 person-years translates to $5 million. It’s a stretch to value one-minute increments of time in this manner, but that’s the way it’s been done for decades, and my fellow engineers are sticking to it!

Taking the Red Pill

About 17 years ago, I began awakening from the Matrix—slowly discovering that stroads have more negatives than positives. But the longtime traffic engineer in me still whispers, “These 30,000 trips don’t have anywhere else to go, and in the minds of engineers still in the Matrix, one minute isn’t trivial—it’s $5 million and 27 person-years of time lost per year!” It’s a hard sell to intentionally make 30,000 trips take longer, all for small immediate benefits. Long-term benefits often depend on land use changes, which can take decades to fully materialize from the new paradigm of mixed-use zoning and infrastructure.

Reducing speed is win-lose to the engineer. In their minds, when tiny advocacy groups for “community,” or “equity,” or “modal fairness” win, then 30,000 drivers, or the 90% of the public they feel they must defend, lose.

So that’s the challenge: moving from a constant win-lose struggle for the upper hand, to win-win within each discipline’s present “Matrix” paradigm. Seventeen years ago, my search for bridges between these two divides began.

Right Sizing Creates Win-Win Bridging Across the Divide

I finally found some win-win bridging through a process called “right-sizing” while serving as the lead traffic engineer and design strategist for the recently published guidebook on Right-Sizing Transportation Assets. My friend, Chandler Duncan of Metro Analytics, led the project to publish the guidebook. Together, we published a popular 2020 article in Planning Magazine with seven specific strategies. Key among those strategies is to use what I call “place-making alternative intersections,” which can make it possible to “drive slower, but travel faster,” by reducing delay at signalized intersections.

When I read Marohn’s article last week, I looked at Washington Street, otherwise known as Highway 210, through Brainerd, Minnesota, to see if such alternative intersections might offer a bridge between what the community wants and what engineers want. A strategy with a lot of potential comes from the “Thru-Turn” family of designs.

Thru-Turn Concept for Taming the Stroad

In a Thru-Turn, instead of left-turn arrows at signalized intersections, which consume precious time and often require huge space for “double left” storage lanes, lefts first go through the intersection, make a U-turn, then turn right. Left turn arrows are no longer needed, and the result is less delay. Normally less delay means the trip from A to B will be even faster—happy engineer! But it also creates an opportunity to introduce traffic calming so that cruise speeds drop from say 45 to 30 mph, without making A to B take longer. Are engineers still happy? Sure. While the efficiency gains were not used to make A to B faster, they do make it safer without making it take longer. They like that, too. Win-win!

This tool is not new: “Michigan Lefts” have been in Michigan and a few isolated locations for decades. But let’s see what happens when they are tweaked to tame this Highway 210 stroad.

Figure 1 shows “loon turns” at each end for trucks, and back-to-back teardrops in the middle for small vehicles:

Figure 2 zooms in to show a few of the before and after movements. The before movements are dangerous and often require signals to make them safer. After, there are few direct lefts and crossings, which reduces serious conflicts with pedestrians and high-speed traffic. Uncontrolled lefts from driveways and unsignalized intersections are converted to “right-in/right-out” (a long-known access control safety strategy). It also creates pedestrian refuge in virtually the entire median, along with more crosswalk opportunities than before.

The U-turns create chicanes, forcing drivers to slow down. Businesses don’t have direct access and egress anymore, and there is some circuitous travel introduced. But the frequent U-Turns make it easy and often faster, nonetheless. Ever tried to turn left out of a fast-food place onto a stroad? You need a nearly impossible gap in both directions. After several minutes, you either do something stupid, or just turn right and try to U-turn. This formalizes such U-turns, making the environment safer and business friendly.

The present width of the corridor is about 82 feet of total hardscape. The U-Turn sections could end up around 100 feet after accounting for sidewalks. But existing buildings are generally set back at locations where 100 feet could be needed. This new design converts a ton of the hardscape into a more pleasant “streetscape.”

In Figure 3, you can see I’m not a landscape architect. The point is to show we can now plant a lot of trees in the median and roadsides, which were not possible before.

Figure 4 shows the highway as it is right now. Red and yellow show parameters out of sync with a walkable environment. (Disclosure: These cross-sections are from the free Complete Street tool housed at StreetPlan.net, which I created myself. I sponsor the tool through my new firm, Urban Artisans, in a partnership with some Utah-based agencies, and my old firm, Metro Analytics. Once you become accustomed to using this tool, it will take you only 10 minutes to create images like these.)

Figure 5 shows that when the center left turn lane is no longer needed for cars, it can become a planted median with pedestrian refuge. We create room for a better pedestrian experience by narrowing lanes from 12 feet to 10 feet, which is best practice for traffic-calming in sensitive environments, without meaningfully affecting capacity. We also improve pedestrian space by getting rid of the under-utilized parking lane.

Figure 6 is mostly the same as Figure 5, but recognizes that since the median no longer needs to store cars, it also doesn’t need to be 11 feet wide. Seven to eight feet makes for pretty good pedestrian refuge. If you then widen the overall right-of-way from 82 feet to 88 feet (which looks like it wouldn’t negatively affect businesses very much), you have room to add cycle tracks, on top of premium sidewalks and street trees. Abundant trees will contribute to traffic calming, carbon sequestration, property value increases, and pavement longevity (i.e., shade that reduces hot/cold flexing and UV deterioration).

Figure 7 shows the widest part of the U-turn (notice the jeep that made a U-turn). The central median can be quite attractive, and it appears to fit within 96 feet.

How Do We Pay for This?

Say you win over the engineers and they are willing to support this traffic calming design because you gave them a bunch of great safety and “drive slower, travel faster” reasons to do so. They’ll tell you: “I’m on-board…if you’ve got the money.” Cost is an article for another day, and somewhat outside my expertise, but here are some key points:

Reducing Duplicative Infrastructure: Now that the grass is greener on the inside of the fence, say over time you attract 1000 new housing units and many businesses into the general area. That development would have otherwise gone to the town’s fringe, and maybe an entirely different community or state. By reinvigorating infrastructure you already have, you reduce duplicative fringe infrastructure. (Can’t afford to build this? You can’t afford not to!)
New Right-of-Way: These concepts require new right-of-way. Is it written in stone that taxes must pay for that? A project like this is a boon for property owners, but those owners get nothing if they run the price too high to build. Facing that, they may well donate frontage they are taxed on, pay maintenance for, and barely use anyway, in trade for boosting the value of their remaining property.
Business Improvement District (BID): The overall downtown, south of the corridor, will benefit from this. Create a BID, like a homeowners association, where everyone pitches in to maintain the trees, sweep the streets, and maybe even pay off a bond.
Form-Based Zoning: The BID will have more funds if it has more development. Relax usage and height requirements. Remove minimum parking requirements; deal with parking after it’s a problem and not before. Allow residential—even tiny studios—and don’t require ground floor commercial if the area can’t support more commercial. Reduce impact fees. Cut red tape. Help developers make more money in your budding mixed-use area than they could make with “ranchettes” at the fringe.
Parks and Rec: Instead of another 10 acres of grass in Sprawlsville, reframe your view of a park. Spend some of the city’s parks and recreation budget to make key streets just as enjoyable as a stroll through the park.

Summary

If your hopes are pinned on winning over traffic engineers, then you’ve got to find a win-win bridge between what you want and what they want. Right-sizing and Place-Making Alternative Intersections are a few of many tools I’ve discovered to help you do that. Learn more at Urban-Artisans.com, MetroAnalytics.com, and at InnovativeIntersections.org.

(All images for this piece were provided by the author, unless otherwise noted.)