No offense OP but this is one of the stupidest questions I have seen asked for a while.... You are coming on here asking a bunch of strangers if they think anyone will call the cops if they see you smoking, how the fuck can anyone speculate on general liklihood other people will narc (in an area most of us have probably never been no less) if we are only in our own heads? Smoking cannabis is fucking illegal, OFCOURSE there are PLENTY of people in the world that will not hesitate to call the police immediately if they see a crime being committed, the majority of people probably wouldn't bother about weed unless it was near their kids school or someone was just being arrogantly open about it, but if you do it often enough someone WILL call the police on you.
I think people are being a bit harsh on you for smoking and driving, bet half of the haters have done it themselves... Personally I don't think being mildly to moderately stoned/high is detrimental to an experienced regular smokers driving, although because most people aren't that experienced I still do agree it should be against the law to drive high. I actually think it makes you less likely to engage in stupid driving behaviour and I myself have driven high on cannabis many times, I will only ever smoke and drive at times when the roads aren't particularly busy and tend to stick to routes I am well familiar with and that also don't require the greatest deal of attention/skill (for example driving on the freeway), I wouldn't be driving around the CBD in peak hour or anything close! However, smoking WHILST driving is a totally different story (unless its a joint or blunt) because regardless of how the weed affects you, you are still distracting yourself from the road and that is putting your life, as well as the lives of others, at risk.
I don't get why you don't just roll up a joint or a blunt and go for a walk, it really is the safest option imo. If you use some common sense and all you have on you is a lit joint I reckon it is pretty damn hard to get busted with it, if someone calls the cops it will be long gone before they get there.