If you could change one law in your country, what would it be?

The law about speeding! People who drive fast do not get in as much accidents as people who drive slow - statistically that is...

But the accidents they do get in are more likely to be fatal. "Kill your speed, not a child"

If you rose the speed limit though and let those with rapid attention dart all over the place at high speeds while those struggling to take in everything are also driving faster than comfortable to keep up with traffic, things could get much messier.
I did a touch of driving for the first time in years a year ago and discovered that the rules for driving in santa cruz 20 years ago do not apply in LA today. You can't drive 55 with a braking distance you feel safe with or someone will pull in front of you. I was getting rather pissed that through no fault of my own I was constantly having people in front of me that I would hit if they had to slow and it took a couple seconds for me to react, and because i'm in back, i'd get the blame. I'd have to drive 30 mph to guarantee there were no cars cutting in front of me too close for very long. long ago in santa cruz, people gave you the space to make your driving a private interaction with the road. sort of live and let live. here people force you to react to them.

Legalize marijuana. I don't smoke it, but all of the effort and resources put into hunting it down is ridiculous when you compare it to how much they actually recover.

The laws concerning marijuana. I'd also like to see gay marriage being allowed too.