On January 10, the New York City Traffic Mitigation Commission released a series of alternatives to Mayor Michael Bloomberg's original congestion pricing program for the city. The commission is slated to make final recommendations to the City Council and the State Legislature by January 31. With the commission -- and New Yorkers -- at a critical moment in this important debate, what are the alternatives under consideration and what would they mean for the city?

The Background

First, for newcomers to this issue, here are the basics: Last spring, Bloomberg released his PlaNYC 2030 proposal. PlaNYC 2030 is the mayor's environmental and sustainability legacy for the future - more than 100 transportation, housing, energy, land use and environmental programs and proposals that will reduce the city's global warming pollution by 30 percent and create the infrastructure for a city that will have 1 million more residents than it does today.

A key component of PlaNYC 2030 (certainly, the one that has received the most attention and controversy) is the proposal to create a congestion-pricing program that, for the first time, would charge drivers in midtown Manhattan at peak hours. Most of the coverage of this idea has focused on the notion of charging drivers in Manhattan's central business district to reduce congestion. But here's what's equally important: The city's proposal (and the new alternatives) will raise more than $400 million a year to give straphangers more elbow room on the 7 train, cleaner seats on the Bx1 bus and more frequent service on the F train.

In July, the state legislature passed a law that set up the commission, which embarked on a eight-month mission to consider the mayor's plan, outline alternatives and, many environmentalists and others hope, give a thumbs'-up to a three-year demonstration project by March 31, 2008.

The Five Options

The commission's January 10 report is a critical piece to figuring out what's on the horizon for the administration's proposal. (For details, check out the Interim Report itself.) In a nutshell, the commission has added four alternatives to the mayor's plan. They are:

The Mayor's Plan

Vehicles entering or leaving Manhattan below 86th Street from 6 a.m. to 6 p.m. during the week would pay $8, and trucks would pay $21. Driving within the zone would cost $4 for cars, $5.50 for trucks. Vehicles paying a bridge or tunnel toll using E-Z Pass that day would pay only the difference between the toll and the congestion charge, if any. Driving on the FDR Drive and the West Side Highway would be free.

If the mayor's proposal works as planned, it would reduce the number of miles driven in the congestion pricing zone by 6.7 percent and generate $420 million a year in revenues for transit investments. On the other hand, it's a really complicated system to manage, thanks to the intra-zone charge. And despite all the pollution and traffic they generate, taxi and livery drivers would not be charged extra for the trips they make in and out of the zone all day long. Ditto, that 18-wheeler that crossed the George Washington Bridge and came down Second Avenue or Columbus Avenue en route to Midtown, since it paid $30 on the bridge already.

The Alternative Congestion Pricing Plan

This is similar to the Mayor's plan, but it has some key changes:

• The northern border of the congestion-pricing zone would be 60th Street.
• There would be no charge for private vehicles driving within the zone -- only for entering it.
• On the other hand, there would be a charge to drive on the periphery roads.
• Taxi riders within the zone would pay a $1 surcharge.
• The value of the toll offset would be capped at $8, meaning that those trucks on the George Washington Bridge would pay a $13 congestion charge if they cross 60th Street.
• Parking meter rates would go up in the zone, and residential parking tax exemptions would no longer exist in the zone.

This closely resembles a proposal offered by the Empire State Transportation Alliance, a broad coalition of business, labor, environmental and other civic organizations in the city co-chaired by the Regional Plan Association and the General Contractors Association. (Full disclosure: I'm on the alliance's steering committee.)

It would cut congestion a bit more than the mayor's proposal. More important, it would generate an additional $100 million a year to give straphangers, train commuters and bus riders some extra breathing room on their trips throughout the city. Plus, it's a heck of a lot easier to implement, thanks to the elimination of the intra-zone charge. And by eliminating the parking tax exemption and adding a surcharge for cab rides in the congestion zone, it really promotes transit as the best low-cost way to get around Manhattan.

The East River and Harlem River Toll Plan

Bye-bye, congestion pricing. Bye-bye, free bridge crossings. Hello, 24-hour bridge tolls on all river crossings. There would be no toll plazas, so this would be an E-Z Pass-only system and would charge drivers $4 to cross the rivers, no matter when they travel or what crossing they use. This would end the "free" ride on many of the 14 bridges that span the East River and the Harlem River and increase the current toll on those crossings that already have a toll (e.g., on the Henry Hudson Parkway).

The commission estimates that this would reduce miles driven by 7 percent and raise $859 million/year. They may be correct. But last time I checked, East River bridge tolls were what many would call a political "third rail," to borrow a phrase from the transit world. For this to go through, unless the governor and the mayor would have to come up with a way to convince Brooklyn, Queens, and Bronx residents that tolling these bridges does not discriminate against them, or that these new tolls won't create new, unintended traffic jams as people change their driving patterns in response to the new tolls.

The License Plate Rationing Plan

Using a rationing system based on the last digit of the vehicle's license plate, each vehicle would be prohibited from entering the congestion zone (south of 86th Street) once every five days. Cameras and extra police at each of the entry points into the rationing zone would enforce this plan.

Mexico City and Athens have led the way here - and the results were clear in both cities: a new black market in license plates and a stronger market for really old, really dirty, really cheap used cars that came with the appropriate license plate.

The Combination Plan

Like the rationing plan, this isn't congestion pricing per se, except for taxis, which would have an $8 per trip surcharge for trips that begin and/or end south of 86th Street. Instead, it's a series of measures to significantly raise parking costs (not only would the resident parking tax exemption disappear, but the city's parking tax would rise from today's 18.375 percent to 38.375 percent) and dramatically reduce the number of government parking permits in the zone.

This idea doesn't cut down on driving enough to meet the statutory minimum of a 6.7 percent reduction in the number of miles driven in the zone, even though it would raise roughly $660 million/year for transit.

Here's the bottom line: The commission has done a ton of strong analytical work to figure out the pros and cons of the mayor's original proposal, and has added four more ideas for consideration. There may be some fireworks at the commission's January 24 hearings, but the most important news will come on January 31, when the commission issues its final report to the mayor, the City Council and the State Legislature.

Rich Kassel is a senior attorney at the Natural Resources Defense Council, where he focuses on urban air pollution and transportation issues. He also chairs the Tri-State Transportation Campaign, a regional transportation advocacy organization and blogs on a variety of environmental issues on the NRDC Switchboard.