The big picture

 

We believe in small steps, but also in having a clear vision of what success looks like so that we know we’re stepping in the right direction.

 

We need a plan for growth without congestion: how can we grow Chicago’s population and economy without being overwhelmed by traffic congestion?

 

The projects listed below are intended to help us all envision a city prepared for growth without congestion—envision it with enough clarity that we can take significant steps toward achieving it.

 

Mapping the Demand for Better Transit

 

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Mapping the Demand for Better Transit

 

Status: in progress.

 

Where is there enough ridership on buses stuck in traffic to warrant an upgrade to something better—like bus lanes, bus rapid transit, or light rail?

 

ChiHackNight is an open group of civic-minded people interested in harnessing big data to make smarter public policy and planning decisions. They’ve been meeting every week for over four years now. We started a project there called Mapping the Demand for Better Transit.

 

We’re mapping bus ridership, congestion delay, and bus mode share in every segment of street across the city to determine where there's enough to warrant upgrading from buses stuck in traffic to something better—like a dedicated bus lane, bus rapid transit, or light rail. In general, such upgrades do the most good where transit ridership is highest and congestion is worst.


The purpose of Mapping the Demand is to put intiatives from community groups and transit agencies alike in perspective so instead of pet projects and institutional inertia, our major transit investments can be driven and supported by data. 

We want to identify the low-hanging fruit of surface transit investments: where would we get the most bang for the buck? Where are the best opportunities to save the most people the most time? If you compare to car counts, where do bus riders have enough mode share to warrant some priority in the street? If you wanted a really cost-effective way to completely change the way people see public transit in Chicago, where would you start?

 

So far we're doing this in two ways: ridership density (riders per mile) and peak-hour bus frequency. Surveying transportation experts and other cities, transit deserves a dedicated lane when there is enough ridership for about 20-25 buses per hour in the peak direction during the peak hour. Mapping the frequency of buses in the peak hour peak direction shows results that may be surprising: there are 4-7 on Ashland Avenue, for example, and 120 on Michigan Avenue in the Mag Mile.

 

But the decision to create a dedicate transit lane is a lot more complicated than that, of course. And giving buses a dedicated lane is not all you need to ensure fast service—other features such as traffic signal priority, payment before boarding, and boarding through multiple doors become important where ridership is very high. In some places, the buses may come so frequently that they can’t be given signal priority without shutting down traffic on the surrounding street grid, and riders are more likely to be stuck behind other slow-loading buses than car traffic.


This project is intended to identify opportunities for improvement without prescribing specific solutions. Designing transit systems is extremely complex and well beyond the scope of this project. But we have noticed that sometimes new transit projects don’t seem to be founded on particularly good data, or respond to the market demand for the product. We want to provide a kind of base map for transit initiatives, a frame of reference from which to view public investments in transportation infrastructure.