velocity

Today as i was standing outside my balcony i noticed cars driving down the street in opposite directions. Everytime a car is in motion it is in some form of acceleration and velocity. I noticed that they were either positively or negatively accelerating, or travelling at a constant velocity with no acceleration. At the time of the picture the van is moving at a constant velocity of around 30 miles per hour and continued at this rate for about 3 seconds. Before the picture was taken the van was accelerating to this velocity of 30 miles per hour. At the end of the road there is a slowdown zone where the van decelerates with a negative acceleration until it comes to a complete stop and it's velocity becomes zero. The van then positively accelerates increasing it's velocity until it reaches the speed limit.