This map represents the Southern California freeway network as envisioned by Caltrans in 1965, one year after the "710 Extension" was added to the plan.

The Lines highlighted in orange represent hundreds of miles of the plan that were never built and never will be, roughly two-thirds of "the system".

The 710 Freeway extension would add less than 1% capacity to the network that was built.

Does anyone really believe that building another 4.5 miles of this 1965 plan is critical to the completion of the regional network?

The reason two-thirds of the system was not built is that the State did not anticipate the huge increase in land values in Southern California making the purchase of right-of-way prohibitive.

This, coupled with a gross underestimate of future gas tax revenues, led to a major reduction in the State's freeway program. Any route that was controversial was taken off the map.

Why did the 710 Extension remain on the map?  Because redevelopment officials in Alhambra and Pasadena saw the freeway as crucial to attracting financial investment to their redevelopment plans of the day. Pasadena's plans at the time included bulldozing Old Town and constructing high-rise offices.  Parson's Headquarters was planned and their vision was to "be the hub of the wheel with the freeways being the spokes".  This vision was replaced with a vision of preserving the architectural heritage there and it is now called Old Town, a nationally renowned main street revitalization project, which is hugely successful without a freeway.