Traffic lights in the U.S. will generally have red, yellow, and green lights that indicate when you're supposed to stop and go through intersections:
Green means go.
Yellow means slow down and prepare to stop.
Red means stop.
Unless otherwise indicated, you are legally allowed to make right turns at red lights.
Make sure that you check for oncoming traffic from all directions before turning.
Stop signs (red and octagonal in shape) indicate that you must come to a complete stop at the limit line before continuing through an intersection.
Yield signs (red or yellow and triangular in shape) indicate that oncoming traffic has the right of way, and you need to wait for the road to clear before progressing.
You aren't required to come to a complete stop at yield signs, but you should slow down—and if traffic is approaching, you may need to stop anyway.
Signs that indicate where trains cross into automotive traffic are generally marked by an “X" shape and read “Railroad Crossing" or “RR."
These signs are usually accompanied by flashing lights and bells that will warn of an oncoming train.
If you encounter a railroad crossing without lights or sounds, you should come to a complete stop and check the train tracks for any oncoming locomotives.
Speed limits are posted on the sides of roads, and indicate (in miles per hour) the minimum and maximum speeds you're legally allowed to drive in that area.
On the freeway, signs above lanes that read “Only" or “Exit Only" indicate that those lanes do not continue on the main freeway, and drivers will either need to merge or take the exit.
If you're parking on the street, make sure that you read all of the signs around your spot, usually indicating how long you're allowed to keep your car there.
Some areas may only allow people with permits to park on the street, or might prohibit street parking altogether—pay attention to everything written on the signs!