Houston light rail among most energy-efficient

3x less emissions than cars

Steve Hawley, Apr 29, 10.

The Houston light rail system is the most energy-efficient way to travel around the city, and it produces fewer greenhouse gas emissions per passenger mile than most light rail systems nationwide, according to a new report from the Federal Transit Administration.

The Main Street line emits just 0.312 pounds of carbon dioxide per passenger mile, while METRO buses emit 0.536 pounds per passenger mile and the average car emits 0.964 pounds per passenger mile.

Nationally, the average light rail line emits 0.36 pounds of carbon dioxide per passenger mile. Since trains emit the same amount of pollution regardless of how many passengers are aboard, the rail systems with the most ridership generally have the lowest per-mile greenhouse gas emissions, while those with low ridership tend to have relatively high emissions. The lowest emission rate is the San Diego light rail system, with just 0.146 pounds per passenger mile, while the highest rate is Kenosha, Wisconsin, which emits 4.266 pounds per passenger mile - four times greater than an automobile.

The METRO bus system - the ninth-busiest in the country - is also more efficient than the national average, emitting 0.536 pounds of carbon dioxide per passenger mile. The average for the nation’s 50 largest bus systems is 0.643 pounds per passenger mile.

METRO is also significantly more efficient than Dallas Area Rapid Transit (DART). DART carries more passengers than METRO but over a less-dense area, emitting 0.534 pounds of carbon dioxide per light rail passenger mile. Its bus system is the least energy-efficient of the 50 largest bus systems, emitting 1.211 pounds per passenger mile, more than the average car.

Heavy rail, such as the New York City subway system, is even more efficient, averaging 0.22 pounds of carbon dioxide per passenger mile. Again, the systems with the most riders have the lowest emissions rates, while those with few riders have higher emissions rates.

The report also examines commuter rail, which averages 0.326 pounds per passenger mile, and vanpools, which average 0.223 pounds per passenger mile, as well as analyzing other individual systems such as ferries, cable cars, and monorails.

Streetsblog notes that cleaner sources of electricity also make a difference. The San Francisco heavy rail system, which relies extensively on hydropower, is the most environmentally-friendly transit system in the country, emitting just 0.085 pounds of carbon sioxide per passenger mile.

FTA report: Public Transportation’s Role in Responding to Climate Change (pdf, 1.2 mb)