San Marcos drivers headed southbound on I-35 will notice lane shifts and may need to pivot from their usual exit as the Texas Department of Transportation continues working on its four-year plan to improve mobility at I-35 and Hwy. 123.

What’s happening

TxDOT is working on reserving and relocating four ramps along I-35 near Hwy. 123 to help ease traffic backups. Reversing ramps means TxDOT is turning some former entrance ramps into exit ramps and vice versa. This creates a longer ramp for drivers to either exit or enter the highway, minimizing the chance for any traffic to back up onto local roads.

TxDOT permanently closed the southbound exit at Hwy. 123 in September while crews work on building a new one. Drivers looking to exit at Hwy. 123 need to take the CM Allen Parkway exit further north.

The major construction ramp reversals along I-35 can cause some confusion for drivers who are used to taking the same route and exit home every day, said Bradley Wheelis, senior communications officer for the Texas Department of Transportation.

“When you move a ramp, sometimes people can drive past the ramp and not realize [they] just passed [their] exit,” Wheelis said.

The overview

The ramp reversals are part of TxDOT’s I-35 at Hwy. 123 mobility project. In addition to the ramp changes, the project will also improve drainage and reconstruct portions of the frontage roads and the I-35 main lanes over Hwy. 123.
  • Timeline: August 2021-early 2025
  • Cost: $107 million
  • Funding sources: TxDOT, Capital Metropolitan Planning