Yes, it is interesting, thank you for posting it. I did notice this included in the article as well:
"There is no evidence that light rail lines have any significant effect on 
traffic congestion. Light rail increases traffic congestion when the implementation is at-grade and 
traffic signal preemption (traffic light priorities) are set in favor of the trains. A 
University of Virginia  study indicates "that the average additional delays from light rail  transit crossings increase with increasing light rail crossing  frequencies and increasing traffic volumes up to the roadway’s  capacity."[SUP]
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Traffic congestion studies factoring the 
opportunity costs  of light rail emphasize that the occupied space should be efficiently  utilized, such as by the greatest number of travelers. A 2005 report by  the Foundation for Economic Education explains the opportunity costs:
 
"For light rail to reduce traffic congestion, the number of  persons it diverts from driving must exceed the drawbacks of in-street  alignment. When light-rail tracks are built in the street, they occupy  space that could have been used by motor vehicles. The loss of two lanes  of roadway for motor-vehicle travel (three where stations are located)  squeezes the remaining traffic into a narrower facility. In addition,  light-rail trains are typically granted the authority to preempt traffic  signals. This further impedes the flow of motor vehicles."
 "The prospect of carrying up to 500 persons at once in a three-car  light-rail train is the transit bureaucrats’ plan for reducing  automobile trips. Of course, not all 500 light-rail passengers on a  given train are diverted from driving an automobile. Some will be  diverted bus riders. Others will be taking newly generated trips. So the  gain in reduced automobile trips is not as large as the total passenger  ridership. Nevertheless, adding light rail is bound to reduce the  number of trips made in privately owned automobiles."[SUP]
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  No transit line in the United States, except 
New York City, carries as many people as one freeway lane"