FM 423 widening Construction is wrapping up on widening FM 423. In Frisco, the roadway has been widened to six lanes from south of Eldorado Parkway to US 380. Another phase of the project widened the roadway to six and eight lanes from SH 121 to Stewarts Creek Road. Timeline: October 2014-December 2017 (both sections) Cost: $29.8 million (Frisco portion), $49.6 million (southern portion) Funding source: TxDOT