New Tappan Zee Project Numbers Underline Need for Suburban Transit

When the Tappan Zee Bridge/I-287 Corridor study team announced the selection of a transit alternative — “full corridor” bus rapid transit between Suffern and Port Chester and commuter rail from Suffern to Grand Central Terminal in NYC — it also released a “Transit Mode Selection (TMS) Report” (available here) which explains why it made that choice and includes updated cost and ridership numbers for each alternative.

The fundamental characteristics of each transit alternative described in the Alternatives Analysis (the first major document in the environmental review process) have not changed. BRT is still the most effective transit mode for suburb-to-suburb commutes, while the NYC-bound market is best served by commuter rail. However, the TMS report reflects several changes to the project and analysis which emphasize the need for an effective suburban transit system in the I-287 corridor.

Better Bus Rapid Transit Plans, Suburban Growth, and the Impact of ARC

One key change to the project was improved bus rapid transit planning. Compared to the BRT plan in the Alternatives Analysis, the BRT option which the study team chose has more stations, more frequent service, and more dedicated right-of-way. The study team also looked at a full-corridor commuter rail line that did not connect to the Hudson Line. This option avoided the complicated and expensive engineering required to make the direct connection, but scored poorly on ridership and cost-effectiveness.


Almost every alternative has higher projected transit ridership than its counterpart in the Alternatives Analysis. This is probably because the TMS Report projections use 2035 as the study year, not 2025 as the Alternatives Analysis did. Since transportation project planning typically looks 20 years out, this makes sense for a project which may not be finished by 2015. As a result, the new numbers reflect 10 more years of population growth, with very high growth projected to occur in Rockland and Orange Counties.

However, even taking into account 10 more years of population growth, NYC-bound ridership on most new Tappan Zee services drops. This is likely because the Access to the Region’s Core project, which would give commuters in Rockland one-seat rides into Penn Station in NYC, will make service on the Port Jervis and Pascack Valley Lines preferable for many Rockland residents working in NYC. For example, full corridor commuter rail was expected to attract 32,600 NYC-bound commuters per weekday in 2025 according to the Alternatives Analysis, which did not take ARC into account. The same alternative is now projected to attract only 29,600 NYC-bound commuters in 2035.

Cost numbers have been updated from 2004 dollars to 2012 dollars. Not surprisingly, every alternative is now more expensive to build, but BRT is still cheaper than light rail and far cheaper than commuter rail. Including the cost of the new bridge, bus rapid transit would cost $8-9.6 billion, the BRT/commuter rail hybrid the team selected will cost $16 billion, and full corridor commuter rail would cost over $22 billion. The TMS Report also estimates fare revenue and operating costs for each alternative. Bus rapid transit brings in lower revenue but costs far less to operate than commuter rail, and the full corridor BRT systems would cover around 50% of their costs, compared to 30% for full corridor commuter rail.

Cumulatively, these changes make Option 4D, Suffern-Port Chester BRT and Suffern-Grand Central commuter rail, by far the strongest choice in terms of overall ridership. This option had the highest ridership of any alternative in the Alternatives Analysis, at 63,700 weekday riders in 2025. The new projection is that this service will attract 79,900 daily weekday riders by 2035, 13,000 more than any other alternative. Almost two-thirds of these would be cross-corridor, non-NYC-bound commuters. Fare revenue from this alternative would cover 41% of costs, better than all but the BRT-only options.

Public Scrutiny = A More Thorough Analysis

The TMS Report describes a more even-handed analysis of all three transit modes than occurred in the Alternatives Analysis, and demonstrates why the public process is so important. Because it listened to input from project stakeholders, the study team not only improved its understanding of bus rapid transit (going so far as to meet with international BRT planners), but also resurrected an alternative it had dropped from consideration, and ultimately found that it was the best option.

Going forward, the team will have to answer many questions from the public about the logic behind its choice and the assumptions underpinning its analysis (three public meetings will take place between October 28-30; more information here). Had the team operated more transparently and released updated cost and ridership numbers earlier, this necessary discussion could have already begun.

3 Comments on "New Tappan Zee Project Numbers Underline Need for Suburban Transit"

  1. Here’s my attempt at crunching the numbers to see which scenario would do the best to increase relative transit value.

  2. Clark Morris | October 15, 2008 at 9:19 pm |

    If there is going to be a rail commuter option which incidentally would be more productive than the ARC connection for the Port Jervis Line, extending the rail line through White Plains and then east to the New Haven region would be a far better use of limited dollars. The major rail infrastructure will already be built between the east side of the Hudson River and Suffern. If rail is extended to the Stewart Airport, this could be a good way to connect Westchester to it. Electrification could be 3rd rail DC, 12.5KV AC or 25KV AC. There is a Swiss line with 11.5 KV AC that has street running so there are some very interesting possibilities. For allowing connections, rail works better because multiple bus routes can easily feed the trunk. The origin destination pairs are so diverse within the region that serving them with direct bus routes becomes an exercise in futility. Instead look at the S-Bahns of Germany and Switzerland which are integrated with the bus services so that a single ticket (or for most people a monthly or annual pass) is good for rides on all forms of transportation within a given area or set of areas. This makes better use of both bus and rail and can reduce the need for park and ride.

  3. What is left out of this analysis is what is really needed more than ARC – rail lines along Route 287 in New Jersey
    which could connect all the hubs of the NJ Transit spoke
    rail lines from Port Jervis to the Coast Line AND provide
    a connection across the Tappan Zee Bridge to Metro North
    and Amtrak. Once again I was forced to drive on the awful NJ 287 and had a delay of almost an hour due to an accident after Bridgewater. Yet to take public transit
    would require 2 trains and 2 buses and 2 hours and 25 minutes minimum travel time.
    It is not just about going to Manhattan anymore – the traffic in the suburbs is horrendous but unless your points are along the spokes of all lines going to Midtown you cannot reasonably take mass transit.
    If you look at 287 a rail line along its corridor could connect the Coast Line, Northeast Corridor, Raritan Valley, Gladstone, Morris, Boonton and Port Jervis rail lines. With shuttle vans and buses from rail stops on these rail lines people would be happy to be done with the monstrous traffic and use mass transit to get to all the Corporate offices and malls long these points.
    To extend this to MetroNorth and Amtrak would be a major boost to transit connectivity.

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