Final answer:
Interstate 40/Route 66 is the highway that runs right and left ahead in Texas, known for having the Cadillac Ranch art installation near Amarillo.
Step-by-step explanation:
The highway that runs right and left ahead in Texas, specifically mentioned in connection with Cadillac Ranch just outside of Amarillo, is Interstate 40/Route 66. This iconic highway serves as a major east-west artery in the state of Texas and has a rich history as part of the original U.S. Route 66. Visitors to the state often seek out Cadillac Ranch as a symbolic art installation reflecting on consumerism and is indicative of Texas's cultural landmarks along this historic route.