Marylanders were no doubt surprised recently to pay higher tolls and gas taxes on their holiday road trips. The surprises for commuters may not end there.

HB 1515, the gas tax plan approved by state lawmakers and Gov. Martin O’Malley in April, includes little-known provisions that may add insult to injury for cost-conscious commuters. Here are four that commuters should know.

It won’t necessarily fund roads, bridges or highways. Drivers probably assume their gas tax payments will help improve the infrastructure they use. That would be incorrect. The majority of new gas tax revenues will not be used for roads, bridges or highways at all. O’Malley has earmarked $660 million of the first $1.2 billion in revenue for controversial transit projects that gas tax payers don’t use, such as the Purple Line in the Washington suburbs and the Red Line in Baltimore.

It may not fund transportation at all. Lawmakers in Maryland have a long history of raiding the Transportation Trust Fund to pay for non-transportation spending. If past is precedent that fund raiding will continue. When debating HB 1515, legislators included a meaningless provision mandating that a three-fifths majority in the legislature approve future trust fund raids. The provision is meaningless because the Democratic-dominated legislature responsible for prior raids already has a three-fifths majority. Thus, don’t be surprised if politicians soon divert the gas tax revenue away from transportation projects to pay for unsustainable government programs elsewhere.

It will be among the nation’s highest. Independent analysts project Maryland will boast the fifth-highest gas tax in the nation. It will be far higher than neighboring Virginia, Delaware and West Virginia, meaning cost-conscious Marylanders in border counties can easily take their business and their money across state lines.

Lawmakers ignored better alternatives. Our Institute provided lawmakers a thorough study of Maryland’s transportation system and concluded that a 21st century transportation network can be achieved without raising the gas tax.

To maximize the impact of transportation revenue, Maryland needs a performance-based funding strategy to rank transportation projects according to greatest impact on congestion mitigation. Such an approach would yield a measure of hours or minutes saved per dollar spent. Those with the greatest yield would receive funding. The performance-based strategy would replace our de facto “transportation choice” strategy, which results in politically motivated transportation funding that does little to relieve congestion.

Carpooling and telecommuting are far more popular among Maryland workers than transit, according to the U.S. Department of Transportation. Both options reduce or eliminate commute times, cut carbon emissions, lessen stress on infrastructure and encourage greater worker productivity. From 2007-2011, Marylanders were 65 percent more likely to either carpool or telecommute than they were to use transit, and telecommuting is the fastest growing solution to job-related “commutes” in the nation. Maryland policymakers need to incentivize both options for economic, environmental and family benefits.

Lastly, Maryland should allow owners of commercial real estate in specific transportation corridors to elect to impose a surtax on their property to fund agreed-upon transportation projects in the corridor. Such a model could be used to broaden cost-sharing for Maryland’s Red and Purple Line projects, which are expected to cost taxpayers a combined $4 billion.

It’s been said that legislating is a lot like making sausage. I beg to differ. Learning the legislative history of this gas tax is a lot like peeling an onion: the more layers you pull back, the more tears it brings to your eyes.

Christopher B. Summers is president of the Maryland Public Policy Institute, a nonpartisan public policy research and education organization that focuses on state policy issues. He can be reached at csummers@mdpolicy.org.