At the speed traps, cameras will spot you when you drive faster than 30MPH. If you are playing with a friend, he or she can then find you and beat your time to score an easy 50,000 CR. A good trick here is to work with a friend to gain some wealth. Drive just over 30MPH so that your speed is noted by the camera, then have your friend just barely exceed it so that he or she earns a reward. Now speed up so that you just barely exceed your friend's speed. Continue swapping back and forth and each time, one or the other of you can gain an additional reward, making it easy to quickly build up all sorts of resources.