Ultimate Interstates:I-40 Extension
The Ultimate Interstate 40 extension would extend I-40 From its current terminus in Barstow, CA westward along CA-52 through Bakersfield to I-5. Then it would head west following CA-46 over to the coast ending at US-101/I-1 Corridor in Paso Robles. This would also complete a missing link in the Interstate system and connect the lower central valley to the interstate system.
Corridor Routing
Interstate 40 would be extended westward multiplexed with I-15 to the CA-58 freeway interchange. The route would then would follow along the CA-58 freeway to Bakersfield replacing the CA-58 designation. The freeway would continue west along the newly constructed Centennial Corridor which would need to be extended westward to end at I-5 near the Stockdale Highway interchange. From there I-40 would continue noethwestward multiplexed with I-5 to the Lost Hills interchange with CA-46, where it would then travel westward along CA-46 which would be also upgraded to freeway standards. I-40 would then end at US-101/I-1 Corridor in Paso Robles
Purpose and Need
Traffic congestion in the central valley and southern california necessitates a new Interstate quality corridor connecting the coast and Bakersfield with the I-40 and I-15. This would provide a better connection to many of the nations major interstate corridors. Extending I-40 west would complete a missing link in the Interstate system that currently exists by its absence. This would also provide a better alternate route to compliment the I-80 and I-10/I-8 corridors, resulting in less traffic funneling to these corridors.
Auxiliary Routes
While none are planned at this time, auxiliary routes from I-40 could be added along the coast, in Bakersfield, along CA-14 connecting to I-5 at the Newhall pass, and even in the high desert serving Victorville or Apple Valley as well.
Alternate Routing
Another possibility for extending I-40 west of I-5 would be to route it more to the southeast near Taft, CA and along the Cuyama River valley (near CA-166) to end at US-101/I-1 Corridor in Santa Maria instead. Traffic studies would ultimately help indentify which ending would have more of a positive impact to interstate users.
Plausibility
Since the corridor has largely already been updated to interstate standards along most of the CA-58 routing from Barstow to I-5 it is entirely possible that the route could easily be designated as I-40 without much additional investment in interstate construction. there are a few sections of CA-58 in the Tehachapi area that would need to be upgraded and grade separated, and the Centennial corridor would need to be extended west to I-5 to complete the route to I-5. From there the routing west of I-5 is less likely since the CA-46 corridor would need substantial investment to be upgraded to freeway standards. Not that this isnt needed with the growth along the central coast in Paso Robles and the Five Cities region.