Source: NYC DOT, 2000 Manhattan River Crossings, Dec. 2001, p. 34. Splits are for 7 am – 7 pm (two-way).

Table 3 shows that cars account for three-fourths (75%) of traffic on the four East River bridges, although the share varies wildly from one bridge to the next. Buses and commuter vans together constitute 9% of vehicles, and the remainder of bridge traffic, 16%, is commercial vehicles. This last group is split almost evenly between vans used by tradesmen (typically, service and repair workers) and cargo-carrying trucks ranging from 6,000-pound 2-axle trucks to 80,000-pound eighteen-wheelers. (Buses, commuter vans and trucks are treated in Section 9.)

Summing NYC DOT’s daily average traffic volumes on the East River bridges for the year 2000 — Queensboro 183,000; Brooklyn, 148,000; Williamsburg, 108,000, and Manhattan, 76,000 — yields 515,000 trips per day, or 188 million a year. Private automobiles’ three-fourths share of these trips thus amounts to 141 million annually.

Next, we separate these 141 million car trips into commute and non-commute trips. Using the same U.S. census data that gave us county-to-county percentage “splits” in Table 1, we calculate that 117,000 autos carrying 144,000 commuters cross one of the bridges en route to work each day, as Table 4 shows below.

Source: 1990 U.S. Census “Journey To Work” data, increased by 10% to approximate 2000 levels. (NYC DOT Manhattan River Crossings reports show 1990-2000 increase of 14.7% in East River bridge volumes and 11.1% increase for all crossings in and out of Manhattan.) Figures here are consistent with percentages in Table 1.

Based on census data that differentiate commuters who drive alone from commuters who carpool, we can divide the 117,000 daily commute vehicle trips that use an East River bridge into 97,600 single-occupant vehicles and 19,000 carpools. The latter carry 46,000 people (including the drivers), for an average occupancy rate of 2.4 persons per car.

To compute the annual number of these 117,000 daily commute vehicle trips, we assume that each of these cars travels, on average, 45 weeks a year (allowing for vacation, illness, work travel, etc.), 4.5 days per week (i.e., one day every two weeks without driving to work on an East River bridge), and 2 trips a day (since the 117,000 trips are one-way, to work). This yields 405 one-way trips a year (45 x 4.5 x 2). The 117,000 commute vehicles thus rack up 47 million East River bridge trips a year (117,000 x 405).

As it happens, 47 million is exactly a third of the 141 million total trips by private autos. In other words, one-third of all East River bridge car trips are for commuting. The remaining 94 million auto trips qualify, then, as non-work auto trips, as shown in Fig. 3.

From these estimates, and using county population data from the 2000 Census, we can calculate the annual cost an individual will bear from East River bridge tolls, based on the person’s level and type of bridge usage. This is shown in Table 5.

Table 5 shows stark differences in prospective costs from East River bridge tolls among various categories of area residents, with respect to how, and how much, they use the East River bridges. Commuters who will drive alone on an East River bridge will pay $1,510 a year for the privilege (a figure we could also have derived by multiplying the average one-way toll level of $3.72 by the 405 annual one-way trips we assume for bridge commuters). Carpoolers split the cost and thus fare better. Based on the prevalence and occupancy rates of carpools on the East River bridges today, the typical carpooler can expect to pay a little over $600 annually to commute on an East River bridge.

However, the real news in Table 5 appears in the first data column, showing per-person costs of tolls for “everyone else” other than East River bridge commuters — area residents who don’t now, or won’t in the future, drive across an East River bridge to their job every day. Included in this category are people who drive to work in Manhattan on an MTA or Port Authority crossing; people whose car commute stays within a borough or between two “outer” boroughs; people who take transit to work, or walk, bike, or work at home; and non-employed adults.

Sources: 2000 Census population data and BTAP calculations based on 1990 U.S. Census “Journey To Work” data, increased by 10% to approximate 2000 levels (per note to Table 4). “Adults” are defined as persons age 18 to 80.

As the first column of Table 5 shows, these folks can expect on average to feel little impact from East River bridge tolls — a mere $37 per person averaged across the 10 counties as a whole, and just $47 for residents of New York City. Even Brooklynites will only pay around $70 a head, provided they don’t drive daily on an East River bridge.

What is, perhaps, unexpected is the extent to which “everyone else” — adults who don’t use an East River bridge on a daily basis — outnumber the daily commuters, who are a tiny minority. For the 10 counties as a whole, those who don’t drive daily on an East River bridge outnumber bridge commuters (solo drivers and carpoolers combined) by 65 to 1. In New York City alone, the ratio is 50 to 1, and even in Brooklyn almost 35 to 1, as may be calculated from the data in Table 6.

Table 6 reveals how few people regularly car-commute on an East River bridge — just 1.5% of residents of the 10 relevant counties, and under 2% in the 5 boroughs. (Here we are summing the percentages of solo-drive and carpooling commuters shown in the second and fourth data columns of Table 6.)

Even among adult residents of Brooklyn, fewer than 3% regularly commute on an East River bridge; and a third of these travel in a carpool and so can share the cost with the other rider(s). Only one borough or county, Staten Island, sends more than 3% of its residents to work daily via an East River bridge. And because many Staten Islanders who take cars to Manhattan are in carpools, the share of those who commute alone on an East River bridge and thus are subject to $1,500 a year in new bridge tolls is just 2.3%.