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A boulevard is the safest option when reconstructing Lake Shore Drive

April 13, 2014 at 6:32 pm

The recently-released draft Purpose and Need (P&N) statement from the North Lake Shore Drive (NLSD) reconstruction project has at least some issues that need to be fixed before a final version is released. As a guiding document for the reconstruction of the Drive from Grand Ave to the northern terminus at Hollywood, it must seriously identify all of the issues in more detail than it does now. The draft document currently has about four pages dedicated to improving the safety and mobility of drivers, but only a few lines dedicated to bus passengers and a further page for people walking and bicycling along the lakefront and the links to inland neighborhoods. IDOT is also using freeway-standard traffic analysis tools to study Level of Service, another metric that takes into account only car traffic when it comes to streets. Hopefully this and other issues with the current draft statement will be rectified.

I wanted to focus on this, for now:

Vehicle speed studies conducted at twelve locations along the length of NLSD for a 48-hour weekday period showed non-compliance rates with the posted speed limit (40 mph at the time of the study) of 78% in the southbound direction and 95% in the northbound direction, with most compliance occurring only during periods of heavy congestion.

I can faithfully assume that IDOT would want to raise the 40 mph speed limit in this case, since most drivers are exceeding it anyway. I have driven on Lake Shore Drive dozens of times and it feels like an expressway that can be safely driven on at 50 or 60 miles per hour. So what’s the problem with raising the speed limit?

[t]he Drive is a parkway that should conform to the following general roadway standards: lanes should be no more than eleven feet wide with additional width only at curves and other special locations; regularly spaced emergency pull-off bays should be provided rather than continuous paved shoulders and where continuous shoulders are needed, they should be specially treated; minimum width access ramps should be provided; and design speed should be 45 mph or 50 mph with speed limits set at 40 mph or 45 mph. The median should be developed with appropriate plantings. Protective barriers, where necessary to protect pedestrians, should be blended with landscaping”.

(Emphasis mine)

That paragraph is from the Lakefront Plan, which reflects the fact that the Lake Michigan and Chicago Lakefront Protection ordinance states that “no roadway or expressway standards…shall be permitted in the lakefront parks,” where an “Expressway means any primary highway constructed as a freeway which has complete control of access and is designed for speeds in excess of 45 miles per hour.”

Apparently, issues with crashing are also related to the fact that the barriers are too close to the edges of the lanes and leave no room for error, or room for vehicles to errantly leave the lane without hitting something. On northern portions of the Drive, there are fewer crashes because there are fewer barriers, despite speeds being generally higher.

Image: Google Maps.

Image: Google Maps.

Drivers can’t be trusted to drive on Lake Shore Drive at the posted speed limit, and any DOT’s go-to strategy – raising the speed limit to coincide with the 85th percentile – is forbidden. It’s also unlikely that there’s any room to expand the Drive for any significant length, even if it were permitted. What are they going to do?

I believe these factors make a strong case for converting Lake Shore Drive into a boulevard that does not feel like an expressway. In my opinion, Lake Shore Drive has already overstepped the Lakefront Protection ordinance by routing pedestrians and bicyclists under or over the Drive and damaging the lakefront parks with pollution of both the air and sound kind.

Lake Shore Drive as it exists just north of Fullerton. 100 ft in width.

Lake Shore Drive as it exists just north of Fullerton. 100 ft in width.

The only feasible way to reduce speeds and therefore improve driver safety is to take away the “expressway feeling” of the Drive by reducing its size. This should be done for the following reasons, among many others:

  • Give the 60,000+ daily bus riders on the Drive a dedicated lane in each direction and respite from congestion caused by drivers in single-occupancy vehicles.
  • Separate recreational or athletic trail users from those using it for transportation purposes by dedicating additional space for bicycles.
  • Convert what are currently tunnels and bridges to at-grade intersections, with shorter crossing distances thanks to fewer car travel lanes, and possibly removing need for most bridge maintenance by removing the bridges.
Quick Streetmix of Lake Shore Drive as a boulevard, with wide bike lanes, bus lanes with a center median, and two car lanes.

Quick Streetmix of Lake Shore Drive as a boulevard, with wide bike lanes, bus lanes with a center median, and two car lanes.

Two lanes for cars? Am I crazy? No. Lake Shore Drive is supposed to be a boulevard, not an expressway. Short of extensive automated speed enforcement, the only way to ensure that most people won’t speed (and therefore drive safely) is to make it feel more appropriate to drive the 40 mph speed limit, something that can be accomplished by reducing the width of the roadway. To accommodate turns, crossings, et cetera at intersections, the extra space provided by the removal of offramps would be more than sufficient. To accommodate the lessened capacity for cars, we offer better alternatives or introduce a per-mile-driven electronic toll (most of us have an I-PASS, right?) to weed out people who could use an alternate route. The P&N statement already cites heavy traffic backups at several entrances/exits, such as Belmont, as a problem. This is because you’re taking tens of thousands of vehicles and dumping them onto smaller city streets that can’t (and never should) be widened. Reducing the capacity of the Drive would also reduce the amount of drivers on streets further inland. As I’ve already written, this would not cause carmageddon.

Lincoln Memorial Drive along Milwaukee’s lakefront is a much more appropriate design. Image: philontheweb2001/Flickr

If Lake Shore Drive is reconstructed to the same expressway-like standard, potentially with wider curves and more room for “driver error,” it will fail to reduce the number of crashes and will not solve any problems that currently exist. Its design should be one that matches more closely the feeling of driving down a city street a mile or two inland. What it makes up for in less car capacity it will make up for in greater accessibility and safety for all users. We can’t make it wider and we can’t make it faster. We can only fix it by making it a slower boulevard.

Citi Bike Data Explorer

March 31, 2014 at 11:45 pm

Citi Bike, the bike share system launched in New York City last May, just released a ton of its rider data (like Divvy did some six weeks ago). Building off my Divvy Data Explorer, I created the Citi Bike Data Explorer.

Capture d’écran 2014-04-01 à 12.43.17 AM

You can see the layout and dimensions are the same (except temperature data), just with different data. And a lot more trips, covering more time! The dataset, as it exists now, is about 30 megabytes so I advise against downloading it on a cellular connection. It may take a few seconds to load – there are over 5 million trips so far, whereas Divvy had just under a million (Citi Bike has been around since May 2013, and also released data through February 2014).

Some things I immediately noticed that make Citi Bike stand apart from Divvy: A significantly larger amount of members (people who bought annual passes) are using Citi Bike, whereas Divvy users are more evenly split. Citi Bike definitely seems to be for commuting and more “practical” purposes of getting around, whereas Divvy is more heavily used for recreation.

I also noticed a small discrepancy between some of the numbers for passholder rides. The two “Unknown” wedges of the age and gender pie charts should match the “Passholder” wedge of the rider type chart. However, the largest discrepancy is 326 rides (0.0059% of all rides), so it should not impact the intended purpose of the visualization.

Leave your own insights in the comments below, and happy exploring.

Note: I’ve also created a new front page for the three bikeshare-related visualizations I’ve published at bikeshare.transitized.com.

What’s still wrong with Dearborn?

March 21, 2014 at 7:00 pm

I have two clips in a short video to share:

These were just two incidents from tonight’s ride home. In the first you see a driver of some government vehicle in a thru lane of Dearborn cutting across to turn left, against the light. Could have really injured someone if there were a person riding a bike at the wrong moment. At least s/he used a signal, right?!

In the second you see several drivers preparing to turn left on the red arrow. I personally would not have tried to swerve around the turning car, but at least whoever was riding stopped to show the driver that there was, in fact, the most basic of traffic control devices that she ignored.

So why does this really matter? Dearborn is apparently the nation’s best protected bike lane! I think what it shows is that, despite having “great” bike infrastructure on a small part of a street in Chicago, many drivers still just don’t care. And it doesn’t matter if you build the protected lane like this, because the greatest conflict point is still at an intersection.

Drivers in Chicago still have too much reign of the city’s streets. There is not one that prioritizes other modes of transportation over the car. Not even the Berteau greenway, which supposedly puts bikes and pedestrians first. In reality, the street is still for cars first. Our streets are too wide, not forcing drivers to slow down and pay attention, and still permits fast, wide turns and speeding without regard for anyone else walking or biking the streets.

The answer to the not-uncommon incidents in the video above is partly better infrastructure design, which has never really been done in any North American city (to my knowledge). Dearborn does a somewhat decent job at this by staggering signals so bikes proceed first, followed by turning cars, but it’s not good enough (clearly). Is there anything else that really can be done?

If you’ve read this blog long enough you know I like the Dutch way of doing intersections, which makes riding a bike much more pleasant:

But even I’m skeptical that this would work in downtown Chicago. Even if it could fit in the space, would drivers care? No matter how many people are riding on Dearborn (like in warmer weather), I’ve still seen drivers pull some lawless, reckless stunts endangering everyone around them. The other part of the problem is our driving culture – in Chicago, many drivers just don’t seem to care. I’m doubtful that “better education” would work, because bad habits are hard to break, and there’s just too many drivers. I believe the answer lies in infrastructure, but not just bike infrastructure. All streets need to be narrower to reduce the feeling that fast speeds are acceptable. The Loop needs more streets where movement is limited only to non-motorized traffic so incidents like the above can’t happen at all. Outer neighborhoods need narrower streets that truly prioritize bicycle and pedestrian traffic, not just paint and a fancy title. Some of the most dangerous intersections could use all-red phases for motor traffic while allowing bicycles and pedestrians full reign of the street.

You can’t have a city that is friendly to cars and friendly to people, as former mayor of Bogotá Enrique Peñalosa declared. This is important to the significant chunk of Chicagoans that don’t own a car at all. The answer to the problems we still face even when building “better” bike and pedestrian infrastructure is not to just make the single piece of infrastructure better. I believe we have to do it on a wide scale, to blanket the city with improvements so that one mode of transportation is not so dominant over all of the others. I think the real problem with Dearborn is that it’s isolated. It’s the exception to the norm of wide streets prioritized for drivers over all, and it’s time to change that in a meaningful way.

Divvy Data Explorer is live

March 12, 2014 at 7:59 pm

After I created the Divvy Spokes visualization to show the start/end neighborhoods of 2013′s Divvy rides, I wanted to play around with the data a little more to see what kind of trends or patterns emerged. I’m used to using Excel pivot tables to filter data, but Excel wasn’t going to cut it with this much data. That’s where Crossfilter and dc.js came in handy.

dc.js (dimensional charting) is a Javascript library built off of Crossfilter.js and d3.js (the latter was used to make Divvy Spokes). Crossfilter basically enables taking huge amounts of data and creating dimensions that can be used to filter the data. dc.js then uses d3.js to display the charts on a website. This was my first foray into crossfilter and dc.js, so I’m pretty proud that I was able to get it up and running over a weekend (and with time to enter the Divvy Data Challenge). Enter the Divvy Data Explorer:



You can click and drag the small chart below the trips by day chart at the top to select a date range. You can also select any of the bars on the month, day of week, and duration of trip graphs, the wedges in the gender, age, and rider type charts, and click and drag on the time trip started graph to filter data. You can get very specific! Read more…

Divvy Spokes

March 3, 2014 at 7:41 am

Divvy, the bike sharing system in Chicago, is currently running a Data Challenge after recently releasing 2013 user trip data. I decided to play around a bit with the data just to see trips; when I finally came to something useful I decided to make it more user-friendly and Divvy Spokes was born.

Capture d’écran 2014-03-01 à 8.47.30 PM

It shows the origin-destination pair of every trip taken in 2013, by the neighborhood in which each the origin and destination station is. The visualization, built with d3.js, is a chord diagram. The relationships create the “spokes” of the wheel.

You can roll over an entire neighborhood “arc” (the edge of the wheel, sorted alphabetically) to see the total number of trips taken as well as the neighborhoods a trip went to. The colors represent the “side” of the city the neighborhood is on: downtown, north, northwest, etc.

Capture d’écran 2014-03-01 à 8.51.42 PM

You can also roll over a “spoke” to see the exact number of trips taken between those two neighborhoods, in both directions. This also works for intra-neighborhood trips (where a spoke ‘goes back in’ on itself):

Capture d’écran 2014-03-01 à 8.53.29 PM

Finally, you can filter the data to show all trips, or only those taken by men, women, annual subscribers, and 24-hour passholders. Male/female filtering is only available for annual subscriber trips, since Divvy does not ask a user’s gender when they purchase a 24-hour pass.

Capture d’écran 2014-03-03 à 7.16.23 AM

Since this is Chicago and everyone has a different idea of what neighborhood they live in, I used the City’s neighborhoods dataset as defined by the Office of Tourism (map). This is a fairly objective source, in my opinion, even if I don’t agree with every location. Also, many stations fall on the boundaries of neighborhoods, which could skew the data. It’s possible that in the future you’ll be able to choose your “neighborhood schema,” but these are the neighborhoods for now.

In this data, the first Divvy stations had only been installed for at most 6 months, and the last were installed just as it was starting to get colder out. It’s not surprising to find that most trips are within the same neighborhood or to one directly adjacent, because most trips are under 2 miles, or somewhere around ten minutes in duration. But you can look at some pretty interesting insights using this diagram, like the large number of people biking between Loop and West Loop (like many of my own commuting trips) is mostly subscribers, but it shrinks for 24-hour passholders. Also, the number of trips in Grant Park and Streeterville – with its tourist destinations – rise a lot (proportionately) for passholders, but are not very strong among subscribers.

The data displayed when you roll over a neighborhood arc or a spoke is proportional to the total number of trips in that dataset, not the total number of trips overall. So you’ll notice that the Loop arc has about 125,000 trips in the “show all” dataset, but shrinks to just under 13,000 trips when the “female” dataset is selected, despite the size of the arc shrinking just a bit. Think of the entire wheel as a pie chart with all pieces adding to 100%.

I can’t wait to see what other projects people have developed with Divvy’s data. Leave any of your insights with this data in the comments, as well as any “nice to see” feature requests that I may get around to. This is my first project with d3.js (and I have to thank Stack Exchange contributors for assistance with the transition aspect of the diagram). I’d also invite anyone who wishes to collaborate to do so via GitHub!


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