How many cones are required for a 1,000-foot tangent section of a freeway lane closure with a posted speed limit of 60 mph?

1. 9 cones, placed at a maximum tangent spacing of 2 × S (120 feet).
2. 14 cones, placed at a maximum tangent spacing of 1.25 × S (75 feet).
3. 18 cones, placed at a maximum tangent spacing of 1.0 × S (60 feet).
4. 26 cones, placed at a maximum tangent spacing of 0.67 × S (40 feet).