Felix Salmon calls Charles Komanoff the man who could unsnarl Manhattan traffic, because of his research into congestion pricing for New York’s centrual business district,the area south of 60th Street:
It turned out to be relatively straightforward to calculate a congestion charge that would pay for public transit; Komanoff arrived at a fee of $16 for every vehicle trip into the central business district. But he knew that he could come up with a model that was much more sophisticated. “I gave them what they were looking for,” Komanoff says. “And then I kept on asking myself more questions.”
So, after the report was released in January 2008, Komanoff requested more funding from Kheel to keep plugging away at the spreadsheet. One of the first tasks was to nail down those externalities. That meant figuring out exactly how much New Yorkers’ time was worth and how much of it they wasted in traffic. He started with a Brookings Institution estimate of the value of a US airline passenger’s time — about $53 an hour. Based on salary data from the Bureau of Labor Statistics, Komanoff bumped that up by 20 percent for people in New York City. He wanted to use conservative estimates, so he assumed that a car driver’s commuting time was 25 percent less valuable than an airline passenger’s; if someone was driving for nonwork purposes, their time was 50 percent less valuable. He drew on survey data to peg a taxi passenger’s time at 90 percent of the average air passenger’s; additional passengers — perhaps children — would be worth much less. Eventually, after taking into account the mix of cars, trucks, taxis, and buses in traffic — as well as the number of people in each type of vehicle — Komanoff concluded that the average vehicle in the central business district has a time value of $53.39 per hour; outside the CBD that number falls to $34.44. (Komanoff based some assumptions on his own research, but the spreadsheet allows anyone to plug in their own estimates to see how they affect the results.)
The rest of his calculations are more complicated. To work out the total delay caused by each car, Komanoff turned to a formula devised by UC Irvine economist Ken Small: S = 24.2/[1 + 0.1(V/Vk)4.08], where S is traffic speed, V is number of vehicles, and Vk is a constant that changes from city to city (it was originally set at an arbitrary level of 1,000 for an area of Toronto in 1978). For S and V, Komanoff drew on the city’s estimates of average daytime traffic speeds (8 mph) and volume (870,301 vehicles) within the CBD. This let him calculate the value of Vk, which came out to be 97,105. He then used that value of Vk and his own estimates of traffic volume to come up with a new — and, by his lights, more accurate — value for S. He then ran the equation again to find the value of S when 1,000 cars were added. The difference, divided by 1,000, represented the impact of each individual car.
In the end, Komanoff found that every car entering the CBD causes an average of 3.23 person-hours of delays. Multiply that by $39.53 — a weighted average of vehicles’ time value within and outside the CBD — and it turns out that the average weekday vehicle journey costs other New Yorkers $128 in lost time. At last, urban planners could say just how big the externalities associated with driving are, knowing that the number was backed up with solid empirical analysis.
“The work Komanoff is doing will be essential,” says Tom Vanderbilt, author of Traffic: Why We Drive the Way We Do (and What It Says About Us). “He’s showing the impact of traffic in easy-to-understand language, considering all transport options, and getting away from the idea that transportation happens in a vacuum.”
Kheel hoped that Komanoff’s work would support a plan to offer completely free public transit. But Komanoff found that the system would still be overloaded at rush hour. Drivers had to be encouraged to travel at different times of the day. So he devised a new plan, one that charged both drivers and transit riders different rates at different times. It would charge $3 to cars entering the CBD on weekday nights, $6 for most of the day, and $9 during rush hour. The subway fare also varies, but is always less than the $2.25 it is today: $1 at night, rising to $1.50 as day breaks, and peaking at $2 during weekday rush hours. Buses are always free, because the time saved when passengers aren’t fumbling for change more than makes up for the lost fare revenue. Komanoff’s plan also imposes a 33 percent surcharge on every taxi ride, 10 percent of which would go to the cab driver and the rest to the city.