In any case, if you are riding down a busy 2 lane street with a line of parked cars on your right, ALWAYS keep at least 4 feet (preferably 5) of space between you and those cars as you ride. Someone WILL eventually swing a big car door open unexpectedly right in front of your path without looking. Keeping this buffer space will place you almost in the center of your lane anyway. If you keep pedalling instead of coasting, regardless of how fast or slow you are going, cars in back of you get less antsy about passing you until the road opens up. It's a psychological thing- they think of you as moving along with the traffic if they see your legs moving, rather than seeing you as an unmoving blob they must get around.