Monday’s MTA data dump confirmed what everyone — the dailies, TV, Streetsblog but not, obviously, the New York Post — has been reporting about congestion pricing’s first week: vehicle entries into the congestion zone are down and travel speeds are up. Subway and commuter rail ridership are showing gains as well.
All well and good. Nevertheless, I’m not diving into the happy data just yet.
Why? Because there will soon be a rebound ― a bounceback in driving when traffic moves faster.
Remember Yogi Berra’s lament, “No one goes there, it’s too crowded”? I’ve kept tabs on the Yankee legend since I saw him go bonkers after the umpire signaled “safe” on Jackie Robinson’s steal of home in Game 1 of the 1955 World Series. (I was there.) Yogi’s adage is why I made the rebound effect explicit in my “BTA” congestion pricing spreadsheet model.
Here’s how I model it:
- The toll makes it costlier to drive into the congestion zone, which prices some car trips off the road, via “price-elasticity.”
- With fewer cars, traffic speeds improve in the zone and en route to and from it.
- The time savings spur a rise in car trips to the zone. Some are trips that got priced out, others are trips that gridlock-averse drivers declined to undertake. The volume of rebound trips is estimated with “time-elasticity.”
- The initial rebound shrinks the initial time savings, leading to a drop in ― you guessed it ― rebound trips.
- That decrease frees up some of the road space that was gained and then lost; this bumps up the rebound trips again.
- Rinse and repeat until the pendulum-swings subside and conclude.
All these iterations take a lot of spreadsheet territory, ranging across the model’s 14 weekday and weekend time intervals and six distinct trip types (work, non-work, through, truck, taxi, Uber), each with their own price- and time-elasticities. The whole shebang requires 40,000 equations (the entire BTA has 160,000).
Programming the rebound effect explicit was a slog. But it lets me (or any BTA user ― remember, the latest version is always available via this link) zero out the rebounds and observe the congestion pricing plan’s initial road-clearing effect. The bottom line: with the $9 peak toll and its accoutrements ($2.25 off-peak, new Uber and yellow surcharges, higher truck fees, etc., all coming before the expected subway improvements that the tolls are going to fund), the model projects a 13.2-percent boost to average vehicle speeds in the congestion zone, before the rebound effect; and a 5.5-percent gain with it.
When I laid out my traffic forecasts here last month ("Here’s How We’ll Know That Congestion Pricing Is Working"), I only mentioned the 5- to 6-percent figure. I should have qualified it as including the rebound effect. I did, at least, project a separate, complementary rebound: a 5-percent uptick in trips in yellow cabs, “as the thinning of private car volumes makes taxi use more attractive on account of both faster trips and lower fares due to lesser 'wait times' built into taxis’ fare structure."
What’s it all mean? That the first week’s worth of travel-speed changes shouldn’t be leaned on too heavily, or even much at all. Ditto, upticks in transit ridership.
To be sure, it’s great to see the first flush of data showing fewer vehicle entries and higher speeds. Yes, your Econ 101 professor was right: make something pricier and purchases will decline (except for ostentatious goods or services that advertise the purchaser’s fabulousness ― aka “Veblen goods” after economist Thorstein Veblen, who coined the phrase “conspicuous consumption”).
But out-of-pocket cost isn’t the sole determinant of travel choice. Travel time matters, too. (So, of course, do people’s proclivities for comfort and autonomy and safety, but these are already baked into travel choices and don’t need to be modeled.) And it behooves us critics of highway expansions, who brandish “induced traffic” as an argument against new lanes and roads, to own up to its inverse: unsnarling streets induces motorists (and Uber and taxi users) to drive more.
The most important takeaway from my projected 13.2-percent instant gain in driving speeds in the zone and the far more modest 5.5-percent bump incorporating the rebound effect may not be those precise figures but their ratio, which suggests that only around 40 percent (5.5 divided by 13.2) of the initial jump in speeds will persist.
The moral: relish our quieter, less-stressing streets while you can. Enduring double-digit reductions in vehicle volumes and increases in their speeds almost certainly must await the ramp-up in the toll to $12 in 2028 and $15 in 2031, along with the gradual payoff from digital track signals, station elevators and the other fruits of the congestion revenues ― the congestion pricing “carrot” alongside the toll “stick.”
Congestion pricing is off to a good start, but let’s not gloat. Especially as the other part of the toll’s mission ― a robust stream of congestion revenues ― has yet to be reported.
