Anyone who has frequented taxi rides in New York City will quickly realize that the experience can be quite varied. Unlike Uber, yellow cab drivers generally don't use any form of GPS or traffic technology while making trips. Almost all New Yorkers have experienced a situation where the driver takes a less than optimal route. It probably won't surprise anyone that many taxi drivers end up taking routes that cost passengers more time and money than it should - and we have the data to support it.

One trip that has always bothered me is travelling from midtown to La Guardia International Airport.I live on W 57th St & 7th Avenue in Manhattan and in most trips, my driver's first inclination is to go uptown first towards the RFK Triborough bridge. With the Queensborough bridge a few avenues down offering a more direct route, I found it hard to believe that they could be right. I eventually developed a routine where I would pull up Google Maps or Waze and direct the driver based on the routes given by the app.

I still however wondered whether this general inclination among taxi drivers had any merit across a larger sample size. Were they really taking a better route on average or was there something else going on? I decided to use a taxi data set that included trip and fare data for 170 million rides to answer this question. First I isolated the taxi trips that picked up passengers in a 3 block radius of where I lived, and dropped them off at La Guardia Airport. This amounted to over 150,000 such fares.

The next step was figuring out how to identify what route these trips decided to take. Depending on time of day and current traffic conditions, Google Maps offers different optimal routes. One set of suggested trips from our focus area to La Guardia at 6:30 PM yields the following suggestions:

From the suggested routes provided by Google Maps we learn a number of things. First there are three main paths out of Manhattan towards LGA: The RFK Triborough Bridge, QueensBoro Bridge, and Midtown Tunnel. The second is that the different paths require varying driving distances, with going uptown inevitably covering much more ground.

Matching trips based on distance covered was a little messy since many drivers could opt to take local roads at some point or may have been forced to circle around.Fortunately the taxi data also indicated whether tolls were paid on a particular trip. Of the three waterways, the Queensboro Bridge is the only exit that does not charge a toll while drivers crossing the Midtown Tunnel or Triborough Bridge pay $5.33 with EZ-PASS or $7.50 with Cash. At the very least we could identify whether a driver decided to take the Queensboro bridge, or one of the other two options.

My first step was to plot average fares based on route choice by time of day with a focus first on weekdays. Traffic patterns with respect to rush hour commutes look very different Monday through Friday versus the weekend.

Looking at the average total fares including tips and tolls paid by passengers on trips through either the Midtown or Triborough are significantly more expensive at all hours of the day.These routes being more expensive isn't all that surprising, since they cover longer driving distances and have an extra fee attached. On average this was costing passengers around $9-10 more per trip, as much as a 33% increase in total price. Subtracting the cost of tolls, this is an additional $4 earned by the driver.

One could argue that this might be worth it for passengers tight on time. So my next step was to examine whether taking the longer and more expensive routes actually saved passengers time. Plotting average number of minutes by type of trip at different hours of the day yielded the following:

For most of the day there is a negligible difference in how long this trip takes regardless of route. During rush hour periods 6am - 9am in the morning and 4pm - 6pm taking the Queensboro does begin to take longer. Even in the worst part of the day, the average difference in trip time is less than ten minutes overall. If you're very tight on time then it might make sense to drive more to get there quicker.

How often were the drivers choosing one option versus another? The next chart shows the percentage of trips in a given hour that opted for a toll waterway vs the Queensboro Bridge.

It's not shocking that drivers have a heavy inclination towards using a toll road. In most parts of the day they're getting paid more to drive for around the same amount of time or less. From the taxi operator's standpoint they're certainly taking the best route to La Guardia but in many cases for the consumer not so much.

Overall it will cost you much more to take the Triborough or Midtown tunnel, and may not save you all that much time. If you're not tight on time to catch a flight directing the driver towards the Queensboro can yield significant savings. Better yet, passengers are probably best off pulling out their smartphone, punching in their trip to see what routes are suggested and then making a decision. Relying on the cab driver will get you an answer from someone who has very different incentives.