Autonomous Vehicles on City Streets
As promised, I will be evaluating the efficacy of dedicated lanes or streets for autonomous vehicles within cities. It's obvious that city roadways have many special considerations such as intersections and mixed traffic usage, but even urban highways differ from rural highways, with a greater frequency of exits and entrances and more complicated traffic interchanges. These factors lead to two contrasting conclusions: that grade-separation of AVs is significantly more important in the urban setting, and that it would be significantly more difficult to implement.
One recent proposal known as Loop NYC would reserve one lane in each direction (with assumed unlimited throughput) on the highways surrounding Manhattan, as well as some of the major crosstown streets to move AVs within the city. This would seemingly create a perfect balance between AV optimization and preserving regular traffic with minimal obstruction, additionally creating park space for pedestrians. Yet, pedestrians would unavoidably and inconveniently be forced onto overpasses to cross this network, a prospect inconceivable for influential urban planners.
Similarly in Atlanta, plans were made early this year to designate a "smart corridor" as a proving ground for AVs, but there were persisting concerns about pedestrian safety particularly near the Georgia Tech campus where students are known to jaywalk. For the time being, the corridor remains a road with intersections and stoplights rather than a converted highway, reducing pedestrian conflicts but tanking AV efficiency. About a month ago autonomous buses were launched on this roadway "without catastrophe."
In states including Nevada and Ohio, emphasis is being placed on deploying "smart roads" with integrated sensors to enable and improve self-driving performance. Having dedicated rights-of-way for this technology helps make it practical and optimizes its use. Especially in dense urban areas, V2I and V2V (vehicle-to-infrastructure and -vehicle) technology is essential for safety and coordination, and these technologies perform best in constrained and exclusive settings.
The Loop NYC project was one of seventeen entries in the Driverless Future Challenge, but the concerns for pedestrian experience prevented it from being selected as the winner. To put their shortcoming in perspective, the winner (Public Square) was concerned exclusively with the urban pedestrian experience. Their mission is to "reclaim the street", and as AVs reduce traffic, they plan to gradually convert parking spaces into parklets until entire streets become linear parks.
This challenge in infrastructure planning is particularly challenging because there is no innovative solution that is fair to all forms of transportation. Individual forms can be completely optimized, but at the great expense of other forms, and there exists no possible optimization of all current and future transit options. The takeaway:
"As long as they share the road with pedestrians, bikes, and human-driven vehicles, self-driving cars will not be able to reach their full utility. The question is, what would cities have to sacrifice to unlock that utility?" -Benjamin Schneider, CityLab
GM created a sequel to the "Futurama" exhibit for the 1964 New York World's Fair. Included below is an incredible video of the entire exhibit, but their rendering of a future city at the end is definitely the highlight. They predict, "Plazas of urban living rise over freeways. Vehicles, electronically paced, travel routes remarkably safe, swift, and efficient. Towering terminals serve sections of the city, make public transportation more convenient, provide ample space for private cars, and from a lower level, covered moving walks radiate to shopping areas that are now truly marketplaces of the world."
Self-driving cars and grade-separated cities in 1964? I'll put my money on GM to be the one to make it happen in 2017.