What does the phrase "space cushion" refer to?

• The space all around your vehicle
  Explanation:

  ""Space cushion" refers to the area surrounding your vehicle, including the space in front, behind, and to the sides. Maintaining a space cushion allows you to react safely to sudden changes in traffic conditions and provides a buffer in case of emergencies."
• The space between the driver and rear seat passengers
• The space between the driver and airbag
• The space between the driver and next traffic signal