The Mass Transit Advantage
MTA's Regional Role in Carbon Reduction: A small increase in transit's carbon footprint typically causes a much larger reduction in the region's carbon footprint.
A key concept to understanding the role of mass-transit in the overall sustainability picture is that of carbon avoidance. Three factors play significant roles:
- Mode Shift - Transportation generates approximately 40 percent of all green-house gases in the United States, with a large proportion coming from single occupancy vehicles. On a per passenger-mile basis, emissions from single occupancy vehicles are up to five times higher than the per-passenger mile emissions of mass transit.
- Land Use - A local mass transit system allows higher density communities. For example, a trip to the grocery or to a child's school in a transit serviced-community tends to be shorter - and frequently is short enough to walk - than a similar trip in an automobile-dependent suburban community. This land use factor is a major contributor to avoided carbon.
- Congestion Factor - Because a local mass transit system decreases vehicle traffic, those that remain on the roads are able to travel faster and more efficiently. When mass transit trips are transplanted to roads, congestion goes up dramatically, causing engines to run more inefficiently and longer for the same trip and increasing greenhouse gas emissions.