Depending on whether you have RSPs pushing in or how many breaks the class gets, you can either split these up or do them in the same lesson time.
Start with a video:
Next, read Go, Go, Go, Stop! by Charise Mericle Harper. Have the students say or use their iPads to find the words "go" and "stop" as you read. Also identify the construction vehicles and their colors.
Afterwards, have the kids color in a traffic light. You could also have them paste colored circles instead.
Then play this video.
Depending on how mobile your kids are, you can also play an extended version of the Green Light /Red Light dance: