Evaluating the Safety In Numbers effect for pedestrians at urban intersections

Recently published:

Average annual 6-hour pedestrian count by location, Minneapolis
Average annual 6-hour pedestrian count by location, Minneapolis


  • Collision risk at 448 intersections in the city of Minneapolis, MN was assessed.
  • The Safety In Numbers phenomenon was observed for both pedestrians and cars.
  • Maps of per-pedestrian crash rates inform discussion of safe vs. unsafe city areas.


Assessment of collision risk between pedestrians and automobiles offers a powerful and informative tool in urban planning applications, and can be leveraged to inform proper placement of improvements and treatment projects to improve pedestrian safety. Such assessment can be performed using existing datasets of crashes, pedestrian counts, and automobile traffic flows to identify intersections or corridors characterized by elevated collision risks to pedestrians. The Safety In Numbers phenomenon, which refers to the observable effect that pedestrian safety is positively correlated with increased pedestrian traffic in a given area (i.e. that the individual per-pedestrian risk of a collision decreases with additional pedestrians), is a readily observed phenomenon that has been studied previously, though its directional causality is not yet known. A sample of 488 intersections in Minneapolis were analyzed, and statistically-significant log-linear relationships between pedestrian traffic flows and the per-pedestrian crash risk were found, indicating the Safety In Numbers effect. Potential planning applications of this analysis framework towards improving pedestrian safety in urban environments are discussed.


  • Pedestrians;
  • Safety;
  • Collisions;
  • Urban planning

Main Street – St. Peter, Minnesota

St. Peter, Minnesota is the county seat of Nicollet County, and home to over 11,000 people. While a bit less than twice the size of Glencoe, more than twice the size of Le Sueur and five times as large as Gaylord, that understates its significance.

This clock in St. Peter is accurate as many 4 times per day.
This clock in St. Peter is accurate as many 4 times per day.

Unlike Le Sueur, Highway 169, which north of town is essentially a freeway, remains Main Street in St. Peter, which makes this one of the busiest Main Streets in Minnesota. Most of that is through traffic, but buildings grow up along roads with the hope the free advertising of road presence attracts some through travelers to divert, and leads to more mind share among those who don’t stop this time, and might in the future. The cost of this is more delay to through travelers who do not stop.

Great efforts have been made in recent years (thanks to the Stimulus bill) to maintain the walkability of this street while ensuring traffic is not delayed too much. Unlike most other Main Streets, there is actually some private economic development activity to construct infill buildings. West of the road, where most of the population lies, is doing much better than the east side.

St. Peter Thrift Store (east side of Highway 169)
St. Peter Thrift Store (east side of Highway 169)

Just based on the logic of the situation, one assumes there is a plan to construct a St. Peter bypass on Highway 169. Actually checking, there is a US 169 Corridor Coalition, which is pushing this (it is endorsed by the City). The status of this is “fictional highways” on one road forum, so nowhere near ready, and given the recent work on Highway 169 through the town itself, probably farther into the future. But as with every line on the map, no “no” is permanent.

St. Peter Armory, For Lease
St. Peter Armory, For Lease

It is the home to Gustavus Adolphus College, atop the hills with a nice view over the Minnesota River Valley. It is farther from Main Street than similar colleges in Northfield, and so doesn’t have quite the level of interaction urbanists might want.

Godfather's Pizza made small town America, and Herman Cain.
Godfather’s Pizza made small town America, and Herman Cain.

Aesthetically, while it is not quite there with Faribault or Owatonna, it is getting close.

I will quote wikipedia on might-have-beens [note [citation needed]]:

In 1857, an attempt was made to move the Territory of Minnesota’s capital from St. Paul to St. Peter. Gov. Gorman owned the land on which the bill’s sponsors wanted to build the new capitol building, and at one point had been heard saying, “If the capitol remains in Saint Paul, the territory is worth millions, and I have nothing.” At the time, St. Peter – a city in the central region of the territory – was seen as more accessible to the far-flung territorial legislators than St. Paul, which was in the extreme eastern portion of the territory, on the east bank of the Mississippi River. A bill was passed in both houses of the Territorial Legislature and was awaiting Governor Gorman’s signature. The chairman of the Territorial Council’s Enrolled Bills Committee, Joseph J. Rolette of Pembina, took the bill and hid in a St. Paul hotel, drinking and playing cards with some friends as the City Police looked fruitlessly for him, until the end of the legislative session, too late for the bill to be signed.[citation needed]Rolette came into the chamber just as the session ended. One might say that the bill was an attempt to “rob Paul to pay Peter.” Today, St. Paul is the second largest city in the state (second only to neighboring Minneapolis), while St. Peter is a relatively small rural town.


Nicollet Hotel - St. Peter
Nicollet Hotel – St. Peter

So of the state’s most important early institutions: Stillwater got the prison, Minneapolis got the University, St. Paul got the capital, and St. Peter got the Asylum.

Main Street - St. Peter (looking west)
Main Street – St. Peter (looking west)



More photos on Flickr.

Cross-posted on streets.mn.

Main Street – Gaylord, Minnesota

Our second stop on the 2014 Minnesota County Seats tour, after Glencoe, is the nearby town of Gaylord, county seat of Sibley County. It won the prize of County Seat after a dispute with Henderson, near the eastern edge of the County.


Gaylord, MN Water Tower
Gaylord, MN Water Tower
2014-11-02 at 11-14-41
Bank (1904) Now Miller Law Office



With a population of 2300, it is just under half the same size as its northern peer, Glencoe. It sets abreast Titlow Lake, as can be seen on this map. As with Glencoe, it is bisected by Highway 22, while the official “Main Street” is Highway 19.

A Court House
A Court House








As with all such county seats, it has a water tower, a court house, a hardware store, a bank turned into a law office, some nice detailed architecture, some of which was ruined by later generations, a post office,  gas stations, roads that are too wide for the traffic, ample parking. This one has a solar powered stop sign with warning lights at the vertices of the octagon (which are reportedly safer).

Electric stop sign
Electric stop sign







Heinke Building
Heinke Building



The retail block in downtown Gaylord: Jimmy's  Pizza, Edward Jones Investments, Goldsmith Eye Care
The retail block in downtown Gaylord: Jimmy’s Pizza, Edward Jones Investments, Goldsmith Eye Care

More photos are available on Flickr.

Cross-posted on streets.mn.

The Mill District should be Loopier: On the creation of new old neighborhoods | streets.mn

Cross-posted at streets.mn: The Mill District should be Loopier: On the creation of new old neighborhoods :

“A key lesson is that it is often easier to grow an urban neighborhood from an existing lattice of structures than try to plop one down on a brownfield site. … Thus we should try not to destroy viable structures or neighborhoods until we have considered renovating them and we have exhausted vacant parcels. Of course, one might say, that is the obvious lesson from urban renewal some 50 years ago.”

The Mill District should be Loopier: On the creation of new old neighborhoods

Gold Medal ParkI have recently spent some time milling about in the Minneapolis Mill District and part of the North Loop neighborhoods. These are hugely changed (and improved) over the past 15 years.The North Loop took off first, with conversion of old warehouses, and then a lot of infill development. The “northeast” part of the neighborhood (1st St from 2nd Avenue N to 8th Avenue N) might be called “complete” in the sense that there are almost no vacant parcels left to develop. There are a few (1st and 4th, 1st and 8th), but many fewer than there used to be, and many of those have developments slated to be built. I put the word “complete” in quotes to indicate that nothing is really ever complete, existing buildings can be remodeled or replaced, so the city remains dynamic. But the first step, filling in the vacancies is largely done. The “southwest” section has many more developable sites.The Mill District came more recently, being constructed on former rail yards and surface parking lots near the River. While there were a few Mill buildings that got renovated (most notably into the Mill City Museum), it comprises much more new construction. The Mill District possesses the Guthrie, (the maybe temporary) Gold Medal Park, one end of the Stone Arch Bridge, and just recently Izzy’s Ice Cream, and is near to the Metrodome and Downtown East. The Mill District, creates temporary street life with the Mill City Farmers Market.

They feel different:

  • First Street N in the North Loop seems to do much better with inviting street-front shops than Second Street S in the Mill District.
  • The Mill District has a greater number of institutional uses (theater, museum) and more parking ramps.
  • Second Street S. is wider, with bike lanes in each direction in addition to one parking lane and one moving lane, with a wider parking lane. I haven’t measured them, but I am guessing at least 10′ wider.
  • Gold Medal Park, while an amenity, reduces the urban feel. The park feels more like a park one might find in suburban Maple Grove rather than a tighter urban park. In part this has to do with younger trees. If this ultimately gets developed (or partially developed), it would change the feel.
  • The light and shadows are different. The buildings on the south side of 2nd Street S and not as high as those on 1st Street N, and thus cast larger shadows. Clearly this changes with time of day and month of year, but it creates a different feel for the pedestrian.

Mill City Farmers Market

Both neighborhoods are in a very real sense new, even if they possess some old buildings, so have time to adapt. Additional infill development will change how both areas operate. But the vitality of the Mill District requires events (shows, markets), while that in the North Loop seems more continuous due to the more permanent retail establishments.

A key lesson is that it is often easier to grow an urban neighborhood from an existing lattice of structures than try to plop one down on a brownfield site. (This is not inherently a criticism of the Mill District, much of which was surface parking, and before that rail yards and had fewer structures to salvage). Thus we should try not to destroy viable structures or neighborhoods until we have considered renovating them and we have exhausted vacant parcels. Of course, one might say, that is the obvious lesson from urban renewal some 50 years ago.


But this still happens: The old Marshall HS in Dinkytown, e.g., or the Colonial Building at Emerald and University on the Central Corridor that has been a vacant parcel for about 7 years now. While construction is well-underway on the Marshall HS site, the Emerald and University site (variously 2700 The Avenue or City Limits Apartments) sits fallow. Things might happen between demolition and construction, so that construction which was planned falls through mid-project.But I think no one is careful enough with existing buildings (not necessarily historically significant ones) in neighborhoods with vacant lots. Fill it with temporary uses at low rent, (e.g Streets.MN wants a clubhouse, or more seriously following the model of the Starling Project) that is far better than using it to store cars or raise weeds.

Izzy's Ice Cream Minneapolis

Open House for Franklin Ave/East River Road Intersection | Bridgeland News

I attended the Open House for Franklin Ave/East River Road Intersection, where the County and consultants revealed their plans. These are described in the (what I thought was defunct) Bridgeland News article.
My views are here.
In short, instead of a Monderman-esque Shared Space, or even a roundabout, they are tweaking the signal timings and reconfiguring the approach lanes. The main change there is on the Franklin Avenue bridge, which will reduce to 1 lane in each direction on the west side, and flare to two lanes at the approach. This will no doubt improve things (in terms of vehicle delay from most approaches and pedestrian delay) over the baseline, and at least it is relatively cheap, but this, as they officials admit, is a short-term fix, and the intersection will need to be revisited post-Central Corridor.

County presents scenarios for Franklin/East River Parkway remake | Bridgeland News

From the Bridgeland News: County presents scenarios for Franklin/East River Parkway remake
From the article:

“Two suggestions bordered on the Swiftian: One was a modest proposal to remove all traffic control from the existing intersection. “When those signals are out, that intersection functions fairly well,” stated one man.”

I was “one man”.
The official alternatives are available here:
Project website
My letter (sent to the team and local public officials) clarifying what I am thinking about, which I sent to the project team is below:

Thank you for hosting the public hearing on the Franklin Ave/27th Street/East River Road intersection. I mentioned the meeting you should consider a shared-space concept (including perhaps a simple roundabout, but without all of the complex signage, separation, etc.) , the ideas I have in mind are illustrated here:
The advantage is that it could cost much less, and could be easily tested (put some covers on the signals, take down the signs, and put up some warning signs telling people upstream they are approaching a new environment, without requiring full reconstruction.
A video showing some of the ideas is here:


(especially at 5:00 into the second video)
I recognize the idea may appear radical to traditional engineering practice, but I think it is worth giving full consideration to, especially on a site like this with no obvious inexpensive solution, with a mix of commuter and parkway traffic, bicycles, and pedestrians, a desire to minimize land taking, and a desire to calm traffic.
Please let me know if you have any questions.
— David

Finally, in addition to having a personal interest in the intersection since I use it daily, I also supervised a Master’s Degree paper: Evaluation of a Roundabout at a Five-Way Intersection: An Alternatives Analysis Using Microsimulation on the intersection by Reuben Collins, which recommended a roundabout.
Unfortunately, judging by their response to comments, the study team clearly has not yet grokked the possibilities of alternatives to conventional (i.e. US standards-based) design, and intends to overbuild and oversign the location.

Simulating Skyways

Two new movies/simulations of the co-evolution of downtown Minneapolis and its skyways system have been postedhere
These are large movies (132 and 137 MB), so be forewarned.
These are based on research done by Michael Corbett as part of his MS classwork and Feng Xie as part of his PhD. The research paper underlying this can be found:
Evolution of the Second-Story City: Modeling the Growth of the Minneapolis
Skyway Network
to be presented at the upcoming World Conference on Transport Research in Berkeley.

Word on the Street about Streetcars

Downtown Journal Online has a follow-up to their article on streetcars in Minneapolis. Seems opinion is mixed. Of course the person from the streetcar museum was in favor.

Met Council endorse University Corridor LRT

From today’s Strib: Met Council vote embraces light rail for St. Paul central corridor.
Is the Central Corridor Light Rail a good or bad investment?

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