Better timing of the lights, so you don't have one change green right as the next one changes red, I avoid this cluster at all costs. Yes, all of this city needs the traffic signal programming seriously overhauled, no more left turn arrows that stay on 1-2 seconds, no more badly synched lights, intelligent infrastructure that adjusts to actual traffic flow, etc.

A lot of the problems with Campbell seem to come down to the lack of forward thinking that didn't happen years ago. No one planned for the amount of traffic it now has, and the worst is between Sunshine and JRF. Most of the "improvements" done by the city and state are just band aids that provide a temporary fix, or no real fix at all.

Adding lanes doesn't ease congestion, it just makes it worse here is an article that gives more insight.

I've been to similar sized cities that use intelligent infrastructure in regards to traffic management, and the difference is astounding. For instance, if a small intersection that sees maybe 1000 cars a day suddenly is getting 100 cars a minute due to traffic diverting from a wreck elsewhere, the lights adapt to the higher volume and work to clear out the intersections, once traffic drops back to normal, they adjust to their regular settings. Bad weather will cause the lights to stay on slightly longer, especially yellow lights, to help prevent people from stopping hard.

The state and city wouldn't even have to change every intersection, at least initially, but focus on the heaviest ones first.