The growing traffic congestion in Texas is a multipronged problem that cannot be solved by one policy. At a time when toll roads appear to be state leadership's primary answer to the dilemma, a bill proposed by Sen. John Carona, R-Dallas, has merit. The legislation would index the gas tax to the Highway Cost Index, or the cost of highway construction over time. According to Carona's office, the bill by 2030 would generate about $16 billion in gas tax revenue — or 31/2 times more than the current gas tax would. Not only would more money be available for transportation...