Demonstrating some key light rail benefits, a new light rail line in Los Angeles is pulling people out of their cars and cutting pollution.

Light rail lines are popping up or expanding in cities around the world, even in the car-centric United States. There are numerous reasons why city planners, city council members, mayors, and common citizens are fans of this transportation option. Before jumping into the Los Angeles (LA) light rail news, let’s just run down a few of the key benefits light rail can provide.

As with all mass transit, light rail is much more efficient than passenger cars (especially when those passenger cars are only being utilized by one person, as is normally the case). Greater efficiency comes with many benefits. Greater efficiency means that less fuel is being burned, which helps a nation, community or individual with their energy independence and energy security. Greater efficiency also means less pollution is being created, which benefits our health and our environment. And greater efficiency means financial savings for the consumer.

Beyond being more efficient due to better utilization of space (more passengers per square foot or square meter), light rail is also more efficient due to the fact that it runs on electricity. Electric vehicles are a few times more efficient than gasoline-powered vehicles.

Aside from the various benefits that come from greater efficiency, another key benefit touted by light rail advocates is that light rail lines stimulate economic development. Fixed rail lines that transport a great number of people and have them boarding and alighting at focused points (stations) are highly attractive to commercial outlets and developers. Time and time again, they have been shown to stimulate a much greater amount of economic development than would have likely occured otherwise.

Change in behavior

Anyway, with that introduction out of the way, the news this week is that LA’s newest light rail line is pulling drivers out of their cars and sticking them into light rail… literally (okay, not literally, but that would be a hot story).

A study conducted by researchers at the University of Southern California evaluated the travel behaviors of experimental households that are located within ½ mile of a station on LA’s new Expo Line (Phase 1 of LA’s light rail development plans) as well as control households with similar characteristics as the experimental households but living beyond ½ mile from the station. Before the opening of the Expo Line, households in both groups had the same travel patterns, with no statistically significant differences in any way. However, after the line was put in, there were notable differences:

After opening, the differences-in-differences approach shows that the experimental group reduced their daily household VMT [Vehicle Miles Traveled] by 10 to 12 miles relative to the control group. That result persists after outlier observations are removed and when alternative statistical methods are used. We interpret this as evidence that the Expo Line reduces VMT among households living within ½ mile of the Expo Line stations.

Of course, less driving means less pollution:

The experimental and control group households had no statistically significant differences in vehicle CO 2 emissions before the Expo Line opened, but after opening experimental group households had approximately 30 percent less vehicle CO 2 emissions than control group households. That “after opening” difference is statistically significant.

And there was one more clear benefit from the light rail line, which I actually didn’t include in my above list of benefits. People who were not that physically active became notably more active, likely due to walks and bike rides to and from the light rail stations. Here’s the study summary on this point:

After the Expo Line opened, those individuals living in the experimental neighborhoods who were the least physically active had the largest increases in physical activity relative to control group subjects. The Expo Line opening was associated with increases in physical activity among approximately the 40 percent of experimental subjects who had the lowest physical activity levels before the line opened. The impact was as high as 8 to 10 minutes of increased daily moderate or vigorous physical activity among those experimental group subjects who were the least active before the Expo Line opened.

This study, using an experimental–control group design, shows that light rail can indeed reduce vehicle miles traveled, reduce CO 2 emissions, and even increase physical activity in one of the most car-centric cities in the world — Los Angeles. If such goals can be achieved with a single light rail line in LA–where the rest of the metropolis beyond the light rail line is still very dispersed and car-oriented–they can surely be achieved in other places through the use of this increasingly popular mass transit solution.

Editor’s note: This is a guest post written by Zachary Shahan, editor of CleanTechnica and Planetsave. The views expressed in this post do not necessarily reflect or represent the views of ABB or its employees.