Rosa banksiae is used along coastal California freeways. Garden forms usually planted not thorny, however. Another that might work is firethorn (Pyracantha). That is wickedly armed.

You might like to find your location in the Sunset Western Garden Book and then see if the plant selection guide portion of the book has anything for you. Similar information is on the Sunset Publishing web site.

Any planting will take time to grow, in the meantime it will not be forming the desired barrier. If there is enough traffic anything you plant will just get stomped down or broken off, while still new and small. Use wire enclosures to fight this, although again determined interlopers will merely destroy whatever you put in their way.

Unless it is something serious enough to keep them out, like a tall metal fence with barbed or razor wire on top.

And somebody who patrols the fence, repairs any places that have been cut through or otherwise damaged.

This post was edited by bboy on Wed, Nov 5, 14 at 14:48

I would try cl Cecile Brunner a pink rose that needs little and is cheap and easy to find in California. I think Monrovia Nurseries website will tell you who has it near by

Pyracantha would work. While it's not a vine, it does have a rather lax, sprawling habit that lends itself easily to training against a fence, wall or forming into an espalier. And it ticks off most of your boxes -- low maintenance, heat and drought tolerant once established, fast grower, evergreen, showy white flowers followed by red orange (usually) berries. And ferocious thorns.......common name of the plant is firethorn.

I vote for Pyracantha also. You will have to be willing to tie up the plant to guide it. Only until you are satisfied with the shape.

Blackberry vines. Can't kill these and they grow fast.