3/25/26, 2:55 PM
ATSSA TRAFFIC CONTROL SUPERVISOR RE- CERTIFICATION EXAM
2026
L=(WS²)/60 for 40MPH or less, Formula for Min. taper
length L=WS for 45MPH or more
The off peak 85th percentile. Which is the speed at or below speed used in
formulas should be which 85% of vehicles travel operating speed in free flow
conditions
125' Distance of L for 25 MPH with 12' Lane width
245' Distance of L for 35 MPH with 12' Lane width
540' Distance of L for 45 MPH with 12' Lane width
1/
10
, 3/25/26, 2:55 PM
660' Distance of L for 55 MPH with 12' Lane width
780' Distance of L for 65 MPH 12' Lane width
L Minimum Merging Taper Length
1/2 L Minimum Shifting Taper Length
1/3 L Minimum Shoulder Taper Length
50'-100' regardless of speed One-Lane, Two-Way Taper (Flagger taper) Length and number of
devices 6 devices 10'-20' apart
50'-100' per lane Downstream taper Length
2L Tangent distance (between tapers)
1/2L Tangent distance before shifting taper
Buffer Space Activity Area Sub-components (3)
Work
Space
Traffic
Space
Recovery Area for errant vehicles: Forgiving design Longitudinal Buffer
Space Protects workers and Motorists
Always completely empty or clear
No vehicles, truck-mounted attenuator, equipment, or
materials
STRONGLY RECOMMENDED: unless there is a
documented reason not to
2/
10
ATSSA TRAFFIC CONTROL SUPERVISOR RE- CERTIFICATION EXAM
2026
L=(WS²)/60 for 40MPH or less, Formula for Min. taper
length L=WS for 45MPH or more
The off peak 85th percentile. Which is the speed at or below speed used in
formulas should be which 85% of vehicles travel operating speed in free flow
conditions
125' Distance of L for 25 MPH with 12' Lane width
245' Distance of L for 35 MPH with 12' Lane width
540' Distance of L for 45 MPH with 12' Lane width
1/
10
, 3/25/26, 2:55 PM
660' Distance of L for 55 MPH with 12' Lane width
780' Distance of L for 65 MPH 12' Lane width
L Minimum Merging Taper Length
1/2 L Minimum Shifting Taper Length
1/3 L Minimum Shoulder Taper Length
50'-100' regardless of speed One-Lane, Two-Way Taper (Flagger taper) Length and number of
devices 6 devices 10'-20' apart
50'-100' per lane Downstream taper Length
2L Tangent distance (between tapers)
1/2L Tangent distance before shifting taper
Buffer Space Activity Area Sub-components (3)
Work
Space
Traffic
Space
Recovery Area for errant vehicles: Forgiving design Longitudinal Buffer
Space Protects workers and Motorists
Always completely empty or clear
No vehicles, truck-mounted attenuator, equipment, or
materials
STRONGLY RECOMMENDED: unless there is a
documented reason not to
2/
10
