Does Minneapolis have too many stoplights?

Sisters Sludge (owned and operated by three sisters for the past two decades) is a neighborhood fixture and a three block walk from my house. It’s a place where I’m known by name and where I’m likely to run into a neighbor.

Needless to say, I’ve spent countless hours gazing out the large windows at the streetcorner. I’ve seen hundreds of route 14 and 46 buses shuttling people across town, and countless airplanes in the distance on final approach to MSP. I’ve watched people walking across the intersection to get a tube for their bike at Dwight’s shop or a maybe haircut from Don the barber.

46th St and Bloomington Ave S

46th St and Bloomington Ave S. Old lights.

The cadence underlying all of this activity was constant. Every thirty seconds, the stoplight would change, just as it had for decades. Many times, as I’ve sat at a red light at midnight with no other car in sight, I always imagined there was an inscription on the aging yellow control box that read, “Neither congestion nor pedestrian nor loop detector nor absence of traffic stays these luminaries from the swift completion of their appointed sequence.”

That all changed a few months ago. Temporary stop signs went up, and the old signals came down. Parts were apparently on delay, or the four way stop signs may have just taken a liking to our great neighborhood corner.

And it was great.

Sure, it took a week or two for people to get used to change, and a few people ran a stop sign. There were car horns. The long OMG! honks, rather than the short taps common whenever someone takes longer than a half second to step on the gas when a light turns green. But the honks followed the congestion into the sunset (down at Chicago Ave) and life on our corner was grand.

Until yesterday, when the new stoplights came online.

Are there really too many?

In 1910, less than 5% of American households owned a car. That jumped to nearly 50% by 1930. In the two decades after WWII, car ownership grew to near ubiquity as we know it today. At first, traffic conflict and control of right of way was not a critical concern. That changed in the post-war boom, which brought us some of the old-generation stoplights being phased out today (and some of the one-way couplets we wish were phased out).

Fast forward a half century. Congestion, especially during rush hours, continues to be a problem. Modern signal controls, loop and camera detectors, advanced modeling, and software give traffic engineers the ability to reduce congestion caused by stoplights.

The city, to this end, received a federal Congestion Mitigation and Air Quality grant and invested city funds to move forward with an $18 million signal re-timing across the city.

This is, in general, a wise and non-controversial investment. Even if there are dozens of extraneous stoplights in Minneapolis, we still need a majority of the 800 or so to stick around. We ought to invest in the technology to get the most out of our existing streets and intersections. Electronics are cheaper than concrete.

But, as the Germans say…

Organisation vor Elektronik vor Beton.
Organization before electronics before concrete.

messintersectionTo an engineer, everything looks like an engineering problem. Data can be collected, models made, software levers configured, and results tracked. I’m familiar with this approach – I work on banking software implementation, not traffic modeling or stoplight controls, but the premise is the same. But to have a successful outcome, we need to define what this outcome should look like (in my world, these are business requirements) and challenge our assumptions (business rules).

For my neighborhood corner, a successful outcome is that: 1) The intersection is compatible with the corner coffee shop, barber, dry cleaner, and bus stop – we don’t have to tear them down or sacrifice them. 2) It’s safe for people, whether they are on foot, on a bike, or in a car. 3) Given these constraints, move vehicles through the intersection as efficiently as possible (after all, backed up traffic is not nice when I’m sitting on the patio).

The reality is that we could have better outcomes at some intersections without stoplights. If we see through the “stoplight timing problem” rather than an intersection problem, we limit our potential outcomes and miss the simplest and most cost-effective solutions. And that’s before even challenging a larger assumption, those that define our streets by their ability to move cars.

Stoplight problems

“I’ve got 99 problems.”
-Your neighborhood stoplight

Congestion

downtown

Flickr/Drew Geraets

Stoplights compress traffic together, bunching them in a way that uses lane space less efficiently. Anyone who has driven one of MnDOT’s famous rural/exurban expressways with many stoplights knows what I mean. Traffic naturally spreads itself out when it stretches out for miles at highway speeds. But the next stoplight bunches everyone back together again, some jockeying for position and most staring at tail lights.

The same thing happens on our local street grid. Stoplights reduce the natural efficiencies of the street grid, instead moving vehicles across the network in pack formation. An anecdotal example comes from my neighborhood stoplight. During the morning, traffic would back up westbound, often queuing two blocks back from the light. The same thing happens eastbound in the afternoon. While the temporary stop signs were up, I never saw more than six cars (about half a block, or to the alley) in queue to go through the four way stop.

It was interesting to observe how the broader system of stoplight controlled collector streets affected this stop sign: Bunches of cars would approach the intersection all at once, causing longer queues than necessary at the stop sign. Where were these cars coming from? Green light waves crossing Cedar or Chicago Avenues.

Friends have reported the same effect at other intersections across Minneapolis.

Safety

When vehicles crash at stoplights, the results are violent and sometimes deadly. It’s in their nature: they’re all or nothing, giving drivers the permission to proceed at speed through an intersection or requiring them to stop. T-bone and high-speed rear end collisions are more common, occurring when drivers run a red light or fail to see a car stopped in their path despite thinking they can proceed.

Fatality_rates

Gratuitously ripped from Streetsblog.

Two died and five were injured a month ago at a north side stoplight. In May, a motorcyclist died when struck by a police vehicle en route to a shooting (the County Attorney declined to file criminal charges, although the State Patrol noted that a contributing factor was an officer “failed to exercise due care in passing through an intersection against a red light”). In September, an innocent driver was killed in Northeast when struck by a fleeing driver presumed to have run a red light.

Alternatives to stoplights don’t necessarily prevent someone from proceeding against the right of way and causing an collision. But four way stops, roundabouts, and shared space are still much safer. Why? Collisions happen at significantly slower speeds, since all users are required to significantly slow down at the intersection. This also makes the intersection much safer for pedestrians. Crash rates, injury rates, and property damages are much lower.

Expense

Stoplights are expensive. New stoplights cost six figures, even as much as a half million dollars. In Minneapolis, replacing existing stoplights is likely less since engineering and components can potentially be reused. But the signal in my neighborhood includes new footings, masts, lights, control boxes, and wiring. There’s also an energy cost – both financially and environmentally – to operate stoplights.

Our city likely has hundreds of millions of dollars of stoplight infrastructure. Saving even a fraction of that has a measurable impact on our city finances, money that could be spent instead on other improvements to our neighborhood corners: Facade improvement funds, historic preservation, street beautification, and other street amenities.

Bad design locked in

In the tactical urbanism community, there’s a saying that “paint is cheap.” But many badly-needed changes on our city’s streets require more than just paint.

If stoplights are expensive to install, they are expensive to reconfigure. Having 800 stoplights across our city reinforces the status quo, for better or worse. Want to try a striping change, add a contraflow bike lane, re-purpose some space inside the curb, or possibly even revert a one-way street to two-way operation? Nope. Unless you have millions.

And millions is what it now takes. This has been the case with projects all across the city: Conversion of downtown streets such as 1st Ave N, Hennepin Ave, or 3rd Ave S to two way operation. Contraflow bus lanes on 4th St. Calming 1st Ave S on the south side. All of these projects required expensive signal reconfiguration.

Stoplight solutions

Remember: It’s okay to break up with our stoplights. We’ve already done it… 31st Street and Grand Ave come to mind. After all, we’re already breaking up with old stoplights as we replace them as part of this citywide program. So why pay through the nose to replace one bad relationship with another?

Others have done it too. Ev’rything’s up to date in Kansas City. They’ve gone about as fer as they can go. But then they decided to go back and removed some stoplights.

Roundabout at Minnehaha Park

Roundabout at Minnehaha Park

Roundabouts

Roundabouts work well when right of way exists. We don’t have that luxury on many corners in Minneapolis, but we do in some places. Roundabouts can be even safer than four way stops because there are no perpendicular movements that tee up t-bone collisions. They can be good or bad for pedestrians and bicyclists. The Minnehaha Park example is unfortunate in that it doesn’t take advantage of the “pork chops” to provide refuge for walkers or bicyclists. But it’s still a good intersection, albeit hard to adjust or experiment to meet changing needs.

Four-way stops

This intersection, 43rd and Upton in Linden Hills, is a great candidate for stoplight removal. It already features a tree-lined refuge island on one side.

This intersection, 43rd and Upton in Linden Hills, is a great candidate for stoplight removal. It already features a tree-lined refuge island on one side.

This is the lowest-cost solution and can work great on streets with low to medium traffic volumes. They are safe: Vehicles know they need to stop under all circumstances – collisions are usually at low speed. They are cheap: Four signs, that’s all. They’re easy to adjust: Remove four stop signs.

With all that money we save by avoiding spendy stoplights, we can afford amenities that make the intersection even safer for pedestrians. Many intersections have 40 feet of pavement in each direction. Some of that can be carved out to provide vegetated medians that serve as a refuge for walkers crossing the street, with the added benefit of channelizing turning traffic so as to be more predictable for other drivers at the intersection (who’s turn is it to go anyways?).

Shared space

Hans_Monderman_2006

Hans Moderman, Dutch traffic engineer who pioneered shared space

At some intersections, it might be worth exploring replacing stoplights with nothing. Shared space is a concept that has caught on in Europe, based on the premise that in the absence of control people will slow down and work their way through a space carefully. With more uncertainty, people naturally negotiate for right of way while also reducing their “risk compensation” (basically, any decision such as speed or distraction which causes them to behave dangerously in the intersection).

Investments usually need to be made to slow vehicles considerably and reduce the perceptibility of things like lanes and curbs. This can possibly require more right of way than we have at many intersections, but it can possibly require more design creativity.

This can be implemented in combination with other approaches, such as what was done at Poynton. In this English village, a high traffic signalized intersection in the town center was reimagined using shared space within the construct of two connected traffic circles. Safety has improved, traffic flows, and the town center is inviting for people and investment in adjacent land use.

Testing the waters

The wonderful thing about stoplights is that they can flash red. At simple four-way intersections, this is a great way to test out traffic flow under an alternate configuration. This should be a standard test for all stoplights at such intersections before deciding on replacement. Why replace when you can decommission?

Even where stoplights need to remain, there’s the opportunity to turn them off for portions of the day. James Lileks, in his signature way, notes how ridiculous it is to wait at stoplights when the stoplight is not serving its purpose:

[The stoplight] exists solely to facilitate the passage of school buses for a 10-minute interval at 4 p.m. but runs 24/7, causing people to sit behind a red at 3 a.m. for no reason, thinking, “adherence to the dictates of traffic signals is one of those unspoken acts that contributes to overall social cohesion.”

Time to test the waters.

What’s your neighborhood stoplight that you really don’t need? Let the world know in the comments section.

Matt Steele

About Matt Steele

Matt's passion is fostering resiliency in local transportation and land use decisions. He's at @matthewsteele.