I want to ride more but always worry about cars on road. :(

Your worries will stop in the next decade once all cars convert to self-driving.

Self-driving cars are very courteous to bikes. 

Joyce says car-free days are more dangerous:

http://pandawhale.com/post/67710/paris-day-sans-cars-shows-us-what-our-cities-can-be

Once we have self-driving cars the focus of the problem will switch to careless and reckless bikers. They will be the cause of most driving accidents, if only by a process of elimination of dumbass car drivers. That said I do see a lot of law breaking by bikers.

Yeah, highway patrol will shift its role to to be more about reckless driving.