A new U-C Berkeley study compared the future sustainability of high speed rail with plane and car travel.
It found a mature high speed rail system would use less energy and produce fewer greenhouse gas emissions.
Researchers accounted for more fuel efficient cars and planes in the future. And they looked at different levels of ridership when calculating greenhouse gas emissions.
Mikhail Chester, co-author of the study, says they factored in different levels of renewable energy use as well.
CHESTER: "Even with the average electricity mix which is projected to get greener in the future there's going to be a larger penetration of renewables, the trains perform pretty well."
The study updates a 2010 analysis with newer more realistic system descriptions and projections.