Solving New York City’s Traffic Congestion Problem

As federal approval issues delay New York City’s congestion pricing plan for another year, a study from CUNY researchers reveals insights on the effects that pricing might have.

The study, published in Sustainability, looked at the effects that a cordon pricing system enforced between 6 a.m. and 8 p.m. would have on transportation demand and traffic emissions in Lower Manhattan. Authors on the paper include Ph.D. student Amirhossein Baghestani and Professor Mahdieh Allahviranloo of The City College of New York.

(The research was conducted prior to the pandemic. For now, work-from-home orders for businesses and the shutdown of retailers, hotels, tourist attractions, and other entities have dramatically reduced vehicular traffic in Manhattan as well as the number of people heading in and out of the city by public transit.)

New York City has the second-worst traffic congestion in the U.S., and it suffers from air pollution as well. While the majority of trips made in Manhattan are actually by public transit, walking, and cycling, cars still take up a lot of space. The paper suggests that tolls could help solve these problems.

Using a computerized model of NYC and surrounding counties that took housing size, income, and other socioeconomic data into account, the researchers simulated the effects of tolls from $5 to $20 for entering or exiting the “central business district”—any part of Manhattan below 60th Street. A $20 toll could reduce traffic congestion by up to 40%, they found. However, most of this relief would happen at the boundaries of the district, and more effort might be necessary to free up inner areas. Tolls also generally increased public transit usage and decreased both greenhouse gas and particulate emissions in the region.

The model revealed how some behaviors might play out. For instance, as the car toll increased from $5 to $15, high-occupancy vehicle (HOV) use went up. This can be explained by people carpooling to split costs. But as the toll reached $20, HOV use decreased. At a certain point, the high cost might be enough that people would rather use other transit options.

Future models could examine whether congestion pricing will be fair and equitable, the authors say, by looking at factors like income levels, environmental justice, and accessibility on public transit.

Beyond SUM

Work By

Mahdieh Allahviranloo (Assistant Professor, Civil Engineering) | Profile 1

Colleges and Schools

The City College of New York