Drivers on two of San Antonio’s most congested highways might get relief sooner than expected.

The Texas Department of Transportation announced plans Wednesday to allocate $1.3 billion for congestion relief projects in major Texas cities. The funding could speed up two San Antonio projects — expansions of parts of U.S. 281 and Loop 410 — by more than a year.

The Transportation Commission, TxDOT’s governing body, is considering $90.1 million toward building an interchange at Loop 410 and U.S. 90, a $180 million project now in its final planning phase. The project also includes some operational improvements on Loop 410 between Texas 151 and U.S. 90.

“This is the fastest-growing population area in our city,” said Mario Jorge, TxDOT engineer for the San Antonio district.

TxDOT planned to begin the project in about a year, said Josh Donat, TxDOT spokesman, but that would be moved ahead with the added state funding.

The project is part of a larger one to improve Loop 410 on the West Side. In October, TxDOT used Proposition 1 funding to break ground on an $82 million interchange at Texas 151. Prop. 1, a ballot measure passed in 2014, sets aside some oil and gas severance tax revenue for the State Highway Fund, though the steep drop in crude oil prices has stemmed that funding source.

The commission also might allocate $81.3 million for the expansion of U.S. 281, a $300 million project that was touted as a candidate for Proposition 7 funding last fall. Starting in late 2017, the November ballot measure will add $2.5 billion in sales tax revenue to the State Highway Fund each year, and after 2020, it will add a projected $430 million in annual vehicle sales tax.

The plan for U.S. 281, which involves converting the section between Stone Oak Parkway and the Bexar County line into a six-lane expressway, is part of a larger project to expand that highway between Loop 1604 and the county line. TxDOT has the money to complete the southern section, but it planned to wait on Prop. 7 funding to begin the northern section.

“The key to this funding is it allows us to begin the right-of-way acquisition, which is significant and could take the better part of two years,” said Mario Jorge, TxDOT district engineer.

Gov. Greg Abbott first proposed the congestion relief initiative in September. Transportation Commission Chairman Tryon Lewis appointed Commissioner Bruce Bugg to lead the initiative by meeting with transportation planners and officials in five Texas cities to determine which projects might be fit for state funding.

“Collectively, the five major metropolitan areas have over two-thirds of the Texas population,” Bugg said. “These are also home to 97 percent of the most congested roads in the state of Texas.”

State legislators found the money for the congestion relief program by ending the use of some gas tax and vehicle registration fee revenue for nonhighway spending — a decision they made last session. That will add $650 million to the State Highway Fund each year.

“This is money that’s basically immediately available,” Bugg said. “We can tee projects up.”

Houston, Dallas, Fort Worth and Austin put forward 12 other projects. The commission discussed them at a workshop Wednesday and will vote on the allocation at its meeting next month.

kblunt@express-news.net

Twitter: @katherineblunt