I'm in the same city as clanrickarde, and this recent vehicular homicide of a biker by a cager does have a lot of riders talking about carrying.
It's not the idea that you'd actually shoot the road rager trying to run you down, it's just the timely display of the weapon that should deter the miscreant from running you down. And you shouldn't even have to "whip out the gun and point it". Just showing it while still in the holster should do the trick.
I've had idiots cut me off in traffic and then laugh. I've had a cager almost slam in to me by not staying in his lane during a left turn. There was a Pima County deputy sherrif in the next lane over, and at the next traffic light I pointed to the car. He rolled down his window and said; "What are you yelling about?". I wasn't yelling, I was just pointing. When I asked the deputy if he saw the car almost sideswipe me, he just laughed. So you can't even count on the law to do something about cagers trying to kill us.
That's why people carry a handgun on a bike. The courts let the cagers off with tickets for turning left into us while on their cell phones and killing somebody out for a cruise, the cops don't care...what are we to do?