Digging Into Dearborn Data: Patterns and Behavior on the Two-Way Bike Lane

The Dearborn bike lanes north of Washington. Photo: Michelle Stenzel, Bike Walk Lincoln Park

Guest contributor Kristen Maddox recently spent a year in Copenhagen as a Fulbright fellow and worked with Copenhagenize Design Company. Now back in the US, she is actively looking for work in bicycle planning and advocacy.

Dearborn Street’s two-way protected bike lanes are equipped with 16 micro-radar sensors with four wireless access points so traffic data can be accessed in “real-time” via cloud-based storage. These technological features make it easy to measure the amount of bike traffic and red-light compliance by bicyclists. Compliance has increased from only 31 percent of cyclists stopping for reds before the lanes and bike-specific traffic signals were installed, to 81 percent afterwards. To determine what other data can be culled from the Dearborn lanes and what this says about the future of cycling in Chicago, I recently performed a much lower-tech study of the facility.

Micro-radar sensors. Photo: Kristen Maddox

I made my observations at Dearborn and Washington Street during morning rush hour on Wednesday July 24th. Given the limited observation period, the results should be taken with a grain of salt. Nonetheless, they suggest that much can be learned from analyzing other intersections across the city, including those currently without bicycle facilities. My inspiration for this investigation came from a study entitled Desire Lines: The Bicycle Choreography of an Urban Intersection, released by Copenhagenize Design Company earlier this year, and feedback from Zach Vanderkooy from the Green Lane Project.

During the two-hour observation period, I kept track of the following:

  • Total number of cyclists and male/female ratio
  • Helmet use
  • Use of the left-turn box
  • Number of cyclists choosing to ride outside of the protected lanes
  • Use of non-standard bikes, types other than single-person road, mountain, hybrid, etc.
  • Number of cyclists carrying cargo (I’ll explain the reason for this later)

The first two items serve as points of reference for understanding Chicago’s burgeoning bicycle culture. In European cities with a high bicycle mode share, helmet use is very low because cycling is not viewed as a dangerous activity. Unlike in most U.S. cities, ridership among women and men is nearly equal. In the Netherlands and Denmark, more women than men ride, whereas in most other countries around the world, most cyclists are male. For an in-depth look at the gender issue read Balance on the Bike: An Essay on the Relationship Between Gender and Cycling by Ma. Fernanda Porras, Claire Stoscheck, and Angela van der Kloof. The gender breakdown of the cyclists I saw at Dearborn/Washington that morning was 32 percent women and 68 percent men (266 men and 123 women).

UntitledSince cities where bicycle use is mainstream also have significantly lower rates of helmet use than those where it isn’t, I also noted how many cyclists on Dearborn were wearing helmets in order to get a snapshot of this facet of Chicago’s current bicycle culture. 60 percent of all riders were wearing helmets. 58 percent of men wore helmets, but 68 percent of women were wearing them. Notably, some of the Divvy riders I observed had their own helmets, which suggests they might be annual members doing their daily commute, rather than 24-hour pass holders.

Speaking of Divvy riders, Divvy bikes accounted for seven percent of all the bikes I saw. The Divvy gender split was 28 percent women and 72 percent men. The highest peak in Divvy ridership was from 8:08 to 8:23. The chart below gives the number of riders during 15-minute increments. I started counting at 8:08 a.m.

Table 1: Cyclists by time, gender, and direction

Bikes Divvy Bikes
Direction: South S North N South S North N
Time Male Female Male Female Male Female Male Female
8:08-8:23 29 17 8 1 4 1 2 2
8:23-8:38 28 21 14 5 2 0 0 1
8:38-8:53 27 20 11 9 0 1 1 1
8:53-9:08 29 17 8 1 2 0 1 0
9:08-9:23 14 4 10 1 0 2 2 0
9:23-9:38 16 5 8 1 2 0 0 0
9:38-9:53 11 2 15 5 0 0 1 0
9:53-10:08 10 4 7 2 1 0 3 0
TOTAL= 389


While the Dearborn lanes allow bike travel in both directions, Washington is one-way eastbound. 100 percent of the southbound cyclists I observed turning left onto Washington used the green left-turn box designed for this purpose. This shows that cyclists are finding the left-turn box to be useful, suggesting that these boxes should be installed elsewhere in the city. Presumably, most cyclists in Chicago, and elsewhere in the U.S., turn left like a car, that is from the left-turn lane. Although some do choose to make a box turn (crossing to the far side of the intersection, turning ninety degress, waiting for the green and then crossing again), they are in the minority.

Because the left-turning cyclists at Washington/Dearborn used the turn box, they voted with their feet in favor of the new facility. This is not to say that some would rather turn without a designated place for bicycles, but it appeared to increase the comfort level of those choosing to use it, which is one of the goals of building bicycle facilities in the first place.

Using the left-turn box on Washington. Photo by Kristen Maddox

The vast majority of bicyclists chose to ride in the protected lanes. Only two percent rode in the travel lanes. I didn’t witness any conflicts between cyclists riding in the travel lanes and vehicles.

Although I noticed a wide variety of bicycle styles, ranging from road to mountain bikes, the vast majority featured “standard” two-wheel frame designs. I did see one cargo bike, two adult cyclists (one female and one male) carrying kids in rear child seats, two cyclists (also one female and one male) with empty child seats, and four folding bikes.

30 percent of cyclists I observed were carrying things, including U-locks, on their bikes. Most used panniers, some strapped objects on the top of rear racks, a few used front baskets, and others had U-locks attached to their bike frames or dangling from the handlebars. Not counting U-locks would have made the cargo count much lower.

Untitled5Some of the 70 percent of people not carrying anything on their bicycles might have done so if their bikes had racks, panniers, and/or baskets, since many of their bikes did not already have these accessories. To further encourage the use of bikes for transportation, we need to promote bikes for all kinds of trips, not just riding to work. Shopping by bike or picking up kids can be done just as easily via bike as commuting.

Of course you could carry things in a bag on your back, but it’s easier to carry objects or children on a properly accessorized bike, or one that’s specifically designed for hauling cargo or passengers. 28 percent of all families in Copenhagen own a cargo bike. As more Chicagoans start using bikes for utilitarian trips, it’s likely we’ll start seeing more cargo bikes here as well.

Across Europe, more and more people are using bicycles for utilitarian purposes, such as package delivery and food carts. As everyday cycling becomes more popular here, bike innovations will mushroom to encompass more services, which will in turn lead more people to replace car trips with bike trips, in a sort of virtuous cycle.

Ice cream bike on Chicago Avenue. Photo by Kristen Maddox

In addition to monthly and quarterly bike counts, there is much more that the Chicago Department of Transportation could do to understand current bicyclists’ patterns, tendencies, and behaviors. For example, the Copenhagenize study I referenced earlier shows that while cyclists tend to be portrayed in a negative light, a review of 12 hours of film footage from an intersection outside the company’s office window showed that 93 percent of Copenhagen cyclists obeyed all traffic rules while moving through the intersection. Six percent broke minor infractions, such as stopping for a red light in front of the stop bar or turning right on red, and one percent broke major traffic rules, such as running red lights.

Standard CDOT traffic counts that simply provide basic information, like the number of cyclists and their apparent gender, are certainly important, but the more detailed the info we are able to collect, the better the sense we’ll get of the big picture.

  • Had no idea there were sensors in the ground. We should get a counter, à la Copenhagen or (now) San Francisco. Might prove that it’s actually being used to some newspapers ;)

  • I noticed these a few months ago. Have not seen any data released from them though.

  • Scott Sanderson

    Maybe more people will wait for the red lights if they know someone is counting.

  • Brian

    Why would you wait for a red light if there aren’t any cars coming?

  • Al Lux

    I kind of feel the same way, but then why should a car wait at a red light if there is no traffic?

  • The car is more dangerous and inhibits the senses of the driver. Inside the car it is quieter and lower to the ground and things like parked cars can hide cross traffic. A person on bike or foot is more aware.

  • Al Lux

    Good points, but then when should a bike stop? Only when the biker feels that the situation requires him/her to stop? I fear that this creates a scenario bikers cross the road whenever they want, possibly creating a safety issue. Most bikers are sensible when it comes to these decisions, but some are not.

  • Definitely not. I only go through red when it is a T-intersection (and I am on the top part of the ‘T’), or a small one-way stop light intersection, like Wilson and Racine. I wouldn’t go through a big intersection. I like to think many people are sensible, but some aren’t, you’re right.

  • Red lights play into this, how?

  • Because you just do. I’m not going to argue about stop signs, I slow and go through them, because they are predictable. Stop lights aren’t, people come out of nowhere.

  • Al Lux

    By the way, this discussion reminds me of a topic I think Streetsblog should explore: driver education, and to a much lesser extent, biker education.

    The point is that driver education in this country is a total joke. My wife comes from a northern european country and she was incredulous at the whole licensing procedure. The test is a joke, there is no emphasis on safety – for example when she was at a four-way intersection with the instructor sitting next to her she looked over her shoulder before turning right too look for bikers. Because you know there is thing called a blind spot. The instructor tore into her and said that was unacceptable. In the Netherlands they teach drivers to open the car door with their right hand so they are forced to look over their shoulder when they open the door. There are plenty of things like this that are absent from US driver education.

    So Streetsblog editors, if you ever want to do some investigative reporting, think this would be an excellent topic.

  • Thanks for the suggestion.

  • Colin Murphy

    How in the world did you get this many data points just standing on the street counting? Did you do it in real time or film it and then analyze later? Impressive either way.

  • Melissa Urbanski

    Bikers must stop for red lights – especially the special bike
    traffic lights they’ve built for us. We are at a place in building a
    biking infrastructure in Chicago where if we want drivers to be
    supportive of our efforts, we need to campaign for drivers’ respect. This won’t happen if we’re not following the
    rules of the road – even if some of those ‘car’ rules don’t make complete sense
    for bikes. Are bikes slower moving
    vehicles? Yes. Are cars more dangerous than bikes? Absolutely.
    Does this mean we can Idaho Stop at all red lights? No.
    For every bike that stops at red lights (and I stop at all of them), drivers
    only remember the bike that blows through a busy intersection. Why should a driver call her alderman and ask
    for more protected bike lanes in her neighborhood, if the only bikers she
    remembers are the ones that don’t follow the rules anyway?

    I was
    at the stop light at Milwaukee and Elston yesterday riding home from work. There were at least 10 of us stopped waiting
    for our special light to turn green. Two
    guys on bikes went around all of us and blew the light. Then one of the stopped bikers behind me yelled,
    “Hey! They gave you a light. The least you could do is obey it!” He was joined by some very loud “Yeahs!” from
    the rest of the bikers waiting. And then
    something magical happened. They both
    stopped and came back to wait with us. So
    I say, when you see someone blow a red light – especially a red biker light –
    shame them. Shame those bikers into
    compliance. Only when bikers appear to
    obey the rules of the road – even if those rules are “car” rules – will we get
    everyone on board for more bike infrastructure.

  • Cameron Puetz

    Granted I haven’t seen all of the raw data, but from the data presented some of the conclusions seem to be a logical stretch. Specifically the claim that most cyclists favor the left turn boxes because they’re using them. When there are few alternatives, simply using something is hardly an endorsement. Without talking to them it’s hard to conclude if they truly like the turn box or just use it because it’s there. The same logic could be used to make the claim that cyclists love the sharrows on Milwaukee in Wicker Park.

  • Anonymous

    is a person on a bike with headphones in, or in the middle of a phone call more aware?

    hey, back when only 5% of the population was driving cars, you could probably rely on people’s judgment too; if they were one of the fringe who cared enough about automobiles to have one, maintain it and use it everyday, then they were probably paying attention to its safe operation.

    but if the goal is to get a large % of the population using bikes on a regular basis, with dedicated infrastructure – then you have to make the rules idiot proof, and then demand that everyone follow them all the time.

    having codified rules is the only way that any mode of transportation is seen as legitimate, and it makes things safer for everyone

    and come on, how long is a red light? it is not going to kill anyone to wait it out

  • I agree with you, when you go to cities with much higher mode share of bikes, you find higher compliance: for everyone’s safety.

    Now, though, there are few people biking, and going through a red light to get ahead of car traffic can be safer for the person on a bike, in order to establish a place on the street. The infrastructure for bikes is non existent many places so we’re on our own. In places with codified rules and dedicated infrastructure, it’s much safer and easier to follow.

    Some red lights are very long. Especially if you’re going to make a left-turn the “bike way,” it can take 3 minutes in parts of Chicago, that adds up. Still worth the safety in many places to wait, but if the intersection is empty, I am not wasting my time.

  • Anonymous

    ” going through a red light to get ahead of car traffic can be safer for
    the person on a bike, in order to establish a place on the street.”

    I hear this comment a lot, but is this just you gut feel, or is there some real data to look at? I am guessing it is the former

    Personally, I wait, and while I move through the intersection on green, a number of cars pass me. Those cars don’t have to pass me at a later stage. Makes for a much safer ride than being in front of the cars where they inevitably try to pass you and may squeeze you.

    There, purely based on gut, I just reasoned why it is safer to wait for the red light….

  • It’s the former. At certain lights that I take every day, I know the pattern, and I know I will make it through the next green while the rest of the cars wait at red. Therefore, they don’t end up passing me again. Everyone’s route is different.

  • Mcass777

    Yes we have a light but I really feel unsafe at a light with a group of other bikers, cars on my left, all waiting for the light. If there is no traffic I will roll thru because I have been swerved into twice where the biker in front of me wobbled as they began to peddle. I was barely moving and got my foot down but could feel myself falling into the biker on my right – thankfully not into the car on my left! This has always been a problem on Milwaukee at Grand, Chicago and on Elston at Fullerton.

    Actually Elston/Fullerton is so screwed up that it is way calmer (intentional use of the word) to cross Fullerton north or south along Elston on a red then wait for the green and try to squeeeeze thru with all the traffic. I know the rules and hear what you are saying, it is just safer, for me, in the empty intersection where car flow is nowhere near the bike. If there was a dedicated bike light here, that would help! IS that everywhere, no but these intersections are downright scary.

    Let’s hope the new design of the Elston/Fullerton intersection factors this in.

  • We’ve touched on this but never did an exposé. The first thing I think we’d need to figure out is, “Who designs driver education in Illinois?” I believe it’s the Secretary of State, but then each high school and driver education school has its own curriculum (presumably based on some basic standards). Any help on this is appreciated.

  • I think that most people have a standard operating procedure just like laws 1 and 3 Asimov’s Three Laws of Robotics:

    1. A [person] may not injure a human being or, through inaction, allow a human being to come to harm.

    3. A [person] must protect his or her own existence as long as such protection does not conflict with the First or Second Law.

    (The second law is “A robot must obey the orders given to it by human beings, except where such orders would conflict with the First Law.”)

  • What CDOT is not testing on Dearborn Street is the two-stage left-turn queue box’s position amongst the bike lane, crosswalk, and travel lanes.

    CDOT should install two of these boxes, one where they are now, and a second one between the bike lane and the crosswalk, a space that’s not close to high-speed traffic.

    The other benefit of having the box between the crosswalk and the bike lane is that one does not have to make a left-turn across the oncoming direction of bicyclists.

  • I’ve done this before. You have a tally sheet of a really good design. There are templates in the transportation/traffic planning community.

  • Anonymous

    That sounds great, but is it relevant?
    Statistically speaking 100% of the people who drive while texting have an SOP that includes rule 1 and 3 of Asimov’s law. (I.E. no one drives and texts with the intention to harm other people.) Still doesn’t make it right though


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