Are One-Way Streets Better Than Two-Way Streets for Urban Planning?

A couple of weeks ago, I got back from my trip to Buenos Aires in Argentina. Looking at the title of today's piece, you are probably wondering what urban planning has to do with my vacation in Buenos Aires. At least when I wrote on the Argentinian economy last week, the connection was clearer. But there does happen to be a connection. When I was in Buenos Aires taking taxis, I noticed that there was a lot of traffic. How Buenos Aires did not make the 2018 Top 200 List for the INRIX Global Traffic Scorecard, I will never know because the traffic there was worse than I have experienced in most major U.S. cities. While traveling throughout the city, I also noticed something else: a lot of one-way streets. I began to wonder: is there a connection between one-way streets and traffic congestion? It then got me thinking of the pros and cons of one-way streets. I will address the cons and scrutinize those since they get more coverage in the one-way/two-way debate.

• Negative impact on local businesses and economies. The idea behind this argument is that there is more exposure for the store because cars in both directions see the building. To further that argument, traffic on two-way streets tends to be slower, which gives greater opportunity to notice local businesses. As for impact on the local economies, one would think that increased business revenue and property tax revenue would cover the costs. However, conversions to two-way streets have had mixed results for the local economy (Riggs and Appleyard, 2018; also see case studies here).
• More difficult navigation. There has to be a certain level of awareness to be able to navigate one-way streets, even with such navigation apps as GoogleMaps or Waze. You would think with such apps, overshooting your route wouldn't happen. What I noticed in Argentina (as well as in the United States with Uber and Lyft drivers) is that even with technology, you can miss a turn. 
• Less efficient traffic. This argument is an offshoot of the previous argument. The conventional argument for one-way streets is that directing traffic in one direction allows for more traffic to pass through, usually at a higher speed limit. Many transportation planners find that a higher vehicle moving capacity automatically translates into greater efficiency. However, a study from professors at Penn State and Berkeley (Gayah and Daganzo, 2012) found different results using a trip-serving capacity. Essentially, the time spent navigating the grid is offset by the moving capacity. For shorter trips, this study found that two-way streets were unequivocally preferable. since two-way streets provide more direct routes. As for longer trips, one-way streets did not possess a particular advantage over two-way streets. This does come with some skepticism since two-way street configurations require more left-hand turns, thereby slowing down traffic.
• Are one-way streets less safe? The intuition behind this theory is that one-way streets are more dangerous than two-way streets because the average speed on a one-way street is higher than a two-way street. This makes it particularly hazardous for pedestrians and cyclists. On the other hand, two-way streets have more conflicting maneuvers, most notably left-hand turns.

I am not an urban planner, and such a debate is quasi-public policy at best. From my layperson view, two-way streets seem to be the better of two options. I would nevertheless say that it depends on the layout of the city, amongst other factors, that would ultimately determine whether one-way streets would be more prudent for cities than two-way streets.