In Philadelphia, emissions from the transportation sector, which includes sources such as vehicle traffic, construction equipment and passenger and freight rail, amounted to 28% of the city’s total emissions in 2022 — the same portion of emissions the sector contributed on a national level. In Philly, transportation comes in second to buildings and industry as the top source of carbon emissions. Nationally, transportation is the leading source.
“A well-functioning transit system is extremely important for reducing emissions,” said Serena Alexander, a professor of public policy and environmental engineering at Northeastern University.
Ripple effects could be bad for the climate
A roughly 4% increase in greenhouse gas emissions from transportation in Philadelphia may sound small, but it’s an important slice in a city that aims to get to net-zero by 2050, said Jesse Keenan, director of Tulane University’s Center on Climate Change and Urbanism.
“How many trees do you need to plant to get that back?” Keenan said. “How many homes are you going to have to energy retrofit to make up for that increase in emissions?”
The loss of SEPTA Regional Rail lines in particular could have ripple effects that lead to more climate pollution elsewhere, Keenan said. People living in denser suburban areas along rail lines might choose to move into less dense, more car-dependent areas if they can no longer use SEPTA to commute into Philly.
“I can’t get on the train, … well, why am I paying the housing premium to be co-located near a SEPTA station?” Keenan said. “I’m going to move out … even further afield.”
If the SEPTA cuts push people to buy cars, that could lock them into a more carbon-intensive lifestyle, King said.
“Suddenly they’re driving for every single one of their trips, and it’s going to be very, very hard to get them back onto the transit system,” he said.
Impacts to local air quality, property values and mobility
It’s not just carbon emissions that could increase if the SEPTA cuts went into effect, Alexander said. People without access to cars would lose accessible mobility options. The cuts could also drive down property values near shrinking Regional Rail routes.
“You will see the impacts across the board,” Alexander said. “You will have worse air quality. You would have worse traffic, possibly more fatalities if traffic goes up, freight issues, economic issues.”
In addition to planet-warming greenhouse gases, gas-powered vehicles release unhealthy air pollutants that can exacerbate asthma and other lung conditions.
Emissions of particulate matter and ozone in the Philadelphia area would likely increase as a result of the cuts, said DVRPC Executive Director Ariella Maron.
“If you have more cars on the road, and if those cars are mostly internal combustion engines, you’re going to have more air pollution,” she said. “That goes without saying.”
The Philadelphia-Wilmington-Atlantic City area already fails to attain federal standards for ozone. In its long-range planning, DVRPC tracks air pollution from transportation across the region and needs to ensure projects do not delay the region’s attainment of federal standards. The planning commission worries the SEPTA cuts could make it harder for the region to meet these requirements, and eventually put federal funding for transportation projects at risk, Maron said.