The roughly 200-mile stretch of Interstate 10 from San Antonio to Houston could become more spacious, as the Texas Department of Transportation has raised the idea of adding a third lane to the highway in each direction.

An expansion of I-10 between San Antonio and Houston would be the latest effort to widen the triangle of roads that link the state’s largest cities, Clayton Ripps, TxDOT’s advanced transportation planning director for the San Antonio district, told the Alamo Area Metropolitan Planning Organization recently. New lanes are planned or are already under construction on parts of Interstate 35 that connect San Antonio, Austin and Dallas and on Interstate 45 between Houston and Dallas.

The I-10 project is in the early phases of development, and an environmental review process is just getting underway, TxDOT officials said. Funding for most of the construction has not been identified, but the work likely will be divided into sections, with some stretches being worked on before others, according to Ripps.

One segment of I-10 that does have a funding source is the section from Loop 410 on San Antonio’s East Side to Texas 130 in Seguin. An additional lane in each direction would be built as a managed lane, meaning it would be tolled.

That project was included in the MPO’s long-range transportation plan approved in December, allowing agencies to move ahead in the development process and start conducting the studies required before construction can begin.

A widened I-10 could help accommodate future increases in traffic, both from freight and regular passenger use, officials said.

As census data released last month attested, the areas along I-35 between Austin and San Antonio are some of the fastest-growing in the country. That growth combined with more people in the state overall — Texas added more people than any state from 2013 to 2014 — mean a higher demand on the highways.

“It’s been a gradual increase, but it seems like it has increased quite a bit over the past year or two,” Guadalupe County Judge Kyle Kutscher said about traffic on I-10. “It’s been pretty consistent with the growth we’ve seen in the county and the region.”

Kutscher said he had not seen the additional traffic lead to major problems other than slower travel times.

TxDOT measures daily traffic flows in multiple spots along I-10, and the data generally reflect the increase in vehicles on the highway. In 2010, for example, an average of 33,000 vehicles traveled on I-10 every day at a spot near Seguin. In 2013 at the same place, the average was 36,324.

The I-10 project could also include improving major interchanges, including those to Loops 410 and 1604 on the East Side. Clearances between the road and bridges along the section may also be increased to provide more room for freight trucks, according to TxDOT.

I-10 between San Antonio and Houston passes through three TxDOT districts — San Antonio, Yoakum and Houston — but the project would be jointly managed by just the San Antonio and Houston districts, officials said. The San Antonio district would be responsible for the portion from here to Columbus, about 125 miles away.

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