Traffic Networks and the Closure of the NYC L Train
As a North Jerseyan (and wannabe New Yorker), I have had much experience with the New York City subway system. Even though it is one of the most widely used public transit systems in the world, its trains are fraught with countless delays and maintenance issues everyday. Despite this, it is still the preferred mode of transit in the city because alternatives like buses are subject to NYC’s insane traffic jams. Even though New Yorkers see the subway as their best strategy for their commute because it has the shortest travel time, L-train riders will soon have to find an alternative in April 2019 when the line gets closed for a 15-month long repair project.
According to an article by Catesby Holmes, the MTA seeks to provide multiple ways to appease victims of this so-called “L-pocalypse”. This reminded me of the traffic networks we described in class. Instead of all travelers taking the subway now, the population must be distributed such that a new equilibrium is reached. If too many people begin taking cars or taxis instead of the subway, traffic congestion will worsen and the travel time will increase for everybody. Similar to the equations described in class (ie x/100 where x=number of travellers), we can naturally predict that travel time will increase proportionally with the number of people who choose this route or strategy. The mutual best strategy for everyone would be to have these estimated 275,000 riders distribute themselves across the alternative channels available to them in a way that relieves traffic congestion but still optimizes their travel time. These alternative routes include using regular MTA buses, riding bikes, signing up for a “luxury shuttle” service founded by a startup called “The New L”, and what is proposed to be the fastest alternative: a new fleet of special “bus shuttles”. Holmes describes that
During the L shutdown, 80 new bus shuttles will run across the Williamsburg Bridge, serving an estimated 4,200 L riders an hour. To keep them moving, beginning in April 2019, all cars will be banned from 14th Street, which runs above the L line in Manhattan, turning the busy four-lane artery into a “busway.” And buses will zip across the bridge during rush hours thanks to an HOV rule limiting traffic to vehicles with three or more passengers. Both policies could dramatically increase bus speeds in the impacted area.
Similar to the “hyperloop” route discussed in our class examples of traffic networks, this new “busway” can only succeed if the correct portion of travellers use this route. If all travellers did in fact use this route (which initially seems like the best strategy), the payoff actually decreases; this is because travel time does increase with the number of travellers just by the nature of traffic and bus capacity constraints. Before rolling out these alternatives, the MTA must strongly consider how game theory in traffic networks will affect their riders’ travel times/payoffs.