The subject today, gentle reader, is one near to many hearts, as their primary function of pumping blood throughout the body depends entirely on surviving in this type of situation.
Most importantly, remember these tons of steel and plastic and leather and vinyl are not your friends. Their impressive chrome and shiny grills and fishbowl creating glass plates are not to be trusted. Perhaps the inhabitants of these ton and two-ton monsters would gladly accept your kindness and humility at a restaurant, workplace, or library, but here you are the Pedestrian, that scourge of American society who at this moment is not participating in the culture of Having Nice Things.
First, look both ways. Then look both ways again. On the third look in both directions you have qualified to step off the curb, but be prepared to hurry back should an Important Person hesitate to use the brakes of their finely tuned vehicle.
Once you have stepped fully into a traffic lane, you have committed yourself to a serious thing. This is when you must exercise your humanity in the most delicate interaction known to man, women, or child. It is very important here to demonstrate your humanity and your humility, but you must not overstep the bounds of familiarity. A slight head nod, or a distinct but cautious wave of your hand at hip level is the most effective way to remind the car turning right or speeding towards a left turn across the intersection that you are also a human.
Remember though, that you do not want to over-emphasize the connection. Should you make the driver of this behemoth feel responsible for you, there lies trouble. They must only feel that by their benevolence your life is spared, like lifting a lazy finger to turn a light switch on or off. They must not feel obligated in any way. Then, anger will rise.
Lastly, do not under any circumstance celebrate in any manner upon reaching the other side. It is best to communicate that you are grateful, but aware that your life could have been extinguished in an instant. Perhaps keep your head down, maybe a full body sigh, or even wipe the sweat from your brow. But do not linger if you wish to repeat this feat again.