A quick look at congestion tolling for Boston

I’ve written in these pages before about creating a cordon-type congestion charging zone (à la London) for Boston, and argued for it to be geographically quite large to reduce shunpiking. And I’ve also supported doubling the motor fuels tax — did you know that if we did that today, the price of gas at the pump would not the same as it was at this time last year? But in preparation for a meeting with my state rep this week, I wanted to think a bit more about other possible revenue sources, and in particular about using congestion tolling on our existing toll facilities to generate revenue that could be earmarked for the specific benefit of transit projects that parallel those roadways.

My specific proposal is to double Turnpike tolls in both directions between Millbury and the Back Bay for eight peak hours every day, with the revenues earmarked to support capital and operational expenses of modernizing the Worcester Line. Unfortunately, the public traffic data does not seem to have an hourly breakdown so estimating the revenue collected is a pure shot in the dark. I didn’t let that stop me, though; I just made an assumption that the equilibrium traffic — that is, the daily cars passing each toll gantry after drivers adjust their behavior for the higher tolls — during the peak hours is 50% of the overall average daily traffic at that location. I assumed that the peak-hours surcharge would be a fixed amount exactly equal to the current in-state E-ZPass toll in each location, and came up with the following table using the online toll calculator and the state’s interactive traffic count map (which includes counts for vehicles passing each toll gantry). I also looked at the harbor tunnels and the Tobin Bridge, with the thought being to finance first the Red-Blue Connector and then in the future (part of) North-South Rail Link and the electrification of the Eastern Route.

Here are the numbers (traffic counts and revenue estimates rounded to thousands):

Location Toll ADT Est. revenue
11–11A $0.45 98,000 $22,000
11A–12 $0.25 93,000 $12,000
12–13 $0.25 113,000 $14,000
13–14 $0.25 132,000 $17,000
16–17 $0.35 130,000 $23,000
17–18 $1.00 133,000 $66,000
20–21 $0.35 146,000 $25,000
Total for Turnpike mainline $179,000
Williams Tunnel $1.50 73,000 $54,000
Sumner/Callahan Tunnels $1.50 40,000 $30,000
Tobin Bridge $1.25 84,000 $53,000
Total for Tobin and tunnels $137,000

That’s the daily revenue, so to convert that to an annual amount, multiply by the number of non-holiday weekdays in a year — that varies a bit because of the fixed holidays, but 250 is a good approximation. That gives you $34.2 million in annual revenue on the tunnels-and-Tobin revenue center, and $44.7 million a year on the Turnpike. Multiply that by 30 to get a very rough estimate of how much bonding that revenue could support — all told, about $2.4 billion before interest, which is more than sufficient at current rates to fully electrify the Worcester Line, build Red-Blue, and get construction started on NSRL.

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2 Responses to A quick look at congestion tolling for Boston

  1. samw says:

    And that’s not even including any tolling on I 93! Imagine how much we could raise if we tolled our north south interstate as well as our east west one. I weep I weep

    • And all of that money would immediately go back out the door to the federal government to pay back all of the highway money used on 93 over the decades, so we wouldn’t see it.

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