I still don’t think Uber/Lyft reduce drunk driving

A couple years ago Uber claimed that it had reduced DWIs in Seattle. I analyzed that claim here (and an interesting extension by Lindsay Pettingill here). This claim is now coming back and there’s a pretty compelling test-ground for it: both Uber and Lyft withdrew from Austin, TX early in 2016. A number of media outlets have made the claim that this has increased DWIs in Austin.

So: new data! Maybe it’s time to update my priors! I went and grabbed monthly DWI arrests for 2010-2016 from the Austin Police Department (previous years are not available AFAIK). You can download the data here. Data is missing for August 2010 and 2011 and I have added a dummy variable for months where Uber was operating in Austin (June 2014 to April 2016).

One year is driving the results

That’s the headline finding. First, let’s look at a couple of descriptive graphs. Here’s the year by year total for DWIs in Austin (all graphs are made with my open-source graphing software for making presentation-ready graphs, Playfair!):


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