Portland is a PR machine for light rail & streetcar

Here are Some Facts About Portland Oregon          

You Can Build Your Way Out Of Congestion

Here is a well balanced article on building your way out of congetion  Archived Copy

From page 2 of ADCsummer07:

San Jose is living proof that crowded cities can build their way out of congestion: Between 1989 and 1994, the region gained 100,000 new jobs, yet new road construction cut the delays encountered by the average rush-hour driver in half. ...

In 1984, voters in Santa Clara County (of which San Jose is the seat) approved a ten-year half-cent sales tax for new highways. This allowed the construction of several new freeways and the expansion of several more. As a result, the Texas Transportation Institute estimates that the delay facing each rush-hour commuter declined from 100 hours per year in 1989 to just 50 hours in 1994.

Utah Reduces Congestion With Increased Road Capacity

From UDOT web site: Since the Parkway opened to traffic it is estimated that traffic on I-15, between the U.S. 89/Legacy Parkway/I-15 interchange in Farmington and the I-215 exit in North Salt Lake, has been consistently reduced as much as 20 percent.  Additionally, the Parkway provides a unique "escape route" from the Salt Lake City area northward, when accidents, construction, or other events significantly slows, or even closes I-15.

Full article from Utah Department of Transportation   Local PDF