If headlights fail, how may a spotlight be used?

• The beam must strike the road not more than 50 feet in front of the vehicle.
  Explanation:

  "If headlights fail, spotlight may be used with the beam striking the road not more than 50 feet in front of the vehicle on which it is used."
• The beam must strike the road not more than 100 feet in front of the vehicle.
• The beam must strike the road not more than 150 feet in front of the vehicle.
• The beam must strike the road not more than 200 feet in front of the vehicle.