A new study, Effect of Light-Rail Transit on Traffic in a Travel Corridor, by University of Utah researchers Reid Ewing, Guang Tian and Allison Spain investigated the effects that Salt Lake City's TRAX light-rail system has on vehicle traffic on parallel roadways. This rail system began operating in 2001 and expanded over the following decades with new lines and stations. It currently carries about 53,000 average daily passengers. The study found significant declines in roadway traffic after the LRT line was completed, despite significant development in the area. It estimates the LRT line reduced daily vehicle traffic on the study corridor about 50%, from 44,000 (if the line did not exist) to 22,300 (what actually occurs). The study evaluates the resulting reductions in traffic congestion, fuel consumption, air pollution and parking costs. It estimated that the on that one corridor the LRT saves almost 500,000 gallons of gasoline, prevents almost 10 million pounds of CO2 from being emitted each year, and saved the University of Utah $23.6 million in avoided parking construction costs.