Toll 183A extension The Central Texas Regional Mobility Authority is planning to extend Toll 183A from Hero Way in Leander to SH 29 near Liberty Hill.[/caption]

The Central Texas Regional Mobility Authority approved a $1.2 million work authorization Wednesday to start designing the Toll 183A extension from Hero Way in Leander to SH 29 near Liberty Hill.

The 5.5-mile extension would include three tolled lanes in each direction throughout that segment, said Justin Word, director of engineering with the Central Texas Regional Mobility Authority.

The initiative is the third phase in an ongoing initiative to extend the toll road. Phase 2 of Toll 183A was completed in 2012 and extended the road from RM 1431 to RM 2243.

“We did [Phase] 2 seven or eight years ahead of schedule, and this [phase] is not even scheduled,” Mobility Authority Executive Director Mike Heiligenstein said. “We see the need, and with capital and construction costs where they are, if we got this underway in a 2-year period that would be beneficial.”

The Texas Department of Transportation owns the right of way where the Phase 3 extension would go. In 2012, TxDOT built the frontage roads in partnership with Williamson County. The frontage roads are located near the edge of the right of way to allow for the tolled lanes, Word said.

Wednesday’s work authorization allows the Mobility Authority to start the schematic design and public involvement process. The agency would need to secure environmental clearance before proceeding with any construction.

Word said schematic design involves planning the footprint of where the roadway would go, including locations of entrance and exit ramps as well as toll plazas. It would take about 18 months to complete the design, public involvement process and to gain environmental clearance, he said.

Ideally, Word said construction could begin a year after the agency obtains environmental clearance, and the project would take about three years to complete. He said the agency would still need to secure funding before starting construction.