It's not quite as simple as Republicans opposing transit and Democrats supporting it. It depends what level of government is discussing it. On the local level, demand for better transit can transcend partisan divides.
Jun 8, 2015 Roll Call
DOT Secretary Anthony Foxx and U.S. Senator Orin Hatch (R-Utah) attended the grand opening of the fifth and final rail line of Utah Transit Authority's (UTA) Frontlines 2015 Program, two years ahead of schedule and $300 million under budget.
Aug 21, 2013 Deseret News
<p>In Salt Lake City, advocates for bus riders have asked the state attorney general to investigate whether the Utah Transit Authority has skewed its ridership figures to gain public support for major investments, which they say is a misuse of funding.</p>
Mar 26, 2008 The Salt Lake Tribune