AUSTIN, Texas — In San Marcos, the population has jumped by more than 20,000 people in the past 10 years -- putting lots more cars on the roads.

The Posey Road bridge over I-35 is one of the oldest in San Marcos. The road sits just north of the outlets.

The stores bring in millions of people every year. Tanger Outlets said about 80 percent of shoppers are not from San Marcos.

New Hays County Judge Ruben Becerra said Posey Road is in need of repair.

"It is not very safe with the old standards and designs,” he said.

The road right now goes over I-35, but TxDOT plans to flip it, bringing the interstate over the road.

It will also convert the two-way frontage road into one way and build U-turn lanes. San Marcos Mayor Jane Hughson said it will help traffic, especially during holiday shopping.

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"Whenever we have the day after Thanksgiving, Black Friday, there are so many people coming to the malls,” she said. “It will back up traffic on the highway at Centerpoint, and so this will give us some added capacity."

Capacity they know they will need as more people move into the area.

"What we want to do is be most useful planning for it,” said County Judge Becerra. “Because I am not of the belief that if you don't build it, they won't come."

The area around the intersection is pretty barren now.

The Chamber of Commerce said there are not any businesses they know of pre-planned for the location. They expect that to change once construction is almost finished.

TxDOT said this project is supposed to be done in about two years. Hays County and TxDOT are splitting the $31 million bill.