ATSSA TRAFFIC CONTROL SUPERVISOR RE-
CERTIFICATION (MISSING SOME BASICS)
QUESTIONS AND ANSWERS WITH SOLUTIONS 2025-
2026
Formula for Min. taper length CORRECT ANSWER L=(WS²)/60 for 40MPH or less,
L=WS for 45MPH or more
speed used in formulas should be CORRECT ANSWER
The off peak 85th percentile. Which is the speed at or below which 85% of vehicles travel operating sp
eed in free flow conditions
Distance of L for 25 MPH with 12' Lane width CORRECT ANSWER 125'
Distance of L for 35 MPH with 12' Lane width CORRECT ANSWER 245'
Distance of L for 45 MPH with 12' Lane width CORRECT ANSWER 540'
Distance of L for 55 MPH with 12' Lane width CORRECT ANSWER 660'
Distance of L for 65 MPH 12' Lane width CORRECT ANSWER 780'
Merging Taper Length CORRECT ANSWER L Minimum
Shifting Taper Length CORRECT ANSWER 1/2 L Minimum
Shoulder Taper Length CORRECT ANSWER 1/3 L Minimum
One-Lane, Two-Way Taper (Flagger taper) Length and number of devices CORRECT
ANSWER 50'- 100' regardless of speed
6 devices 10'-20' apart
, Downstream taper Length CORRECT ANSWER 50'-100' per lane
Tangent distance (between tapers) CORRECT ANSWER 2L
Tangent distance before shifting taper CORRECT ANSWER 1/2L
Activity Area Sub-components (3) CORRECT ANSWER
Buffer Space Work Space
Traffic Space
Longitudinal Buffer Space CORRECT ANSWER Recovery Area for errant vehicles:
Forgiving design 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
Termination Area is:
can contain: (2) CORRECT ANSWER Where road users are returned to their normal path
extends from the downstream end of the work area to the last device such as end work zone sign
May contain:
end work zone sign: usually 500' past last device
downstream taper = 50'-100' per lane
Recommended Advanced Warning Sign Spaceing: Urban (low speed) CORRECT ANSWER 100'
Recommended Advanced Warning Sign Spaceing: urban (high speed) CORRECT ANSWER 350'
Recommended Advanced Warning Sign Spaceing: Rural CORRECT ANSWER 500'
CERTIFICATION (MISSING SOME BASICS)
QUESTIONS AND ANSWERS WITH SOLUTIONS 2025-
2026
Formula for Min. taper length CORRECT ANSWER L=(WS²)/60 for 40MPH or less,
L=WS for 45MPH or more
speed used in formulas should be CORRECT ANSWER
The off peak 85th percentile. Which is the speed at or below which 85% of vehicles travel operating sp
eed in free flow conditions
Distance of L for 25 MPH with 12' Lane width CORRECT ANSWER 125'
Distance of L for 35 MPH with 12' Lane width CORRECT ANSWER 245'
Distance of L for 45 MPH with 12' Lane width CORRECT ANSWER 540'
Distance of L for 55 MPH with 12' Lane width CORRECT ANSWER 660'
Distance of L for 65 MPH 12' Lane width CORRECT ANSWER 780'
Merging Taper Length CORRECT ANSWER L Minimum
Shifting Taper Length CORRECT ANSWER 1/2 L Minimum
Shoulder Taper Length CORRECT ANSWER 1/3 L Minimum
One-Lane, Two-Way Taper (Flagger taper) Length and number of devices CORRECT
ANSWER 50'- 100' regardless of speed
6 devices 10'-20' apart
, Downstream taper Length CORRECT ANSWER 50'-100' per lane
Tangent distance (between tapers) CORRECT ANSWER 2L
Tangent distance before shifting taper CORRECT ANSWER 1/2L
Activity Area Sub-components (3) CORRECT ANSWER
Buffer Space Work Space
Traffic Space
Longitudinal Buffer Space CORRECT ANSWER Recovery Area for errant vehicles:
Forgiving design 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
Termination Area is:
can contain: (2) CORRECT ANSWER Where road users are returned to their normal path
extends from the downstream end of the work area to the last device such as end work zone sign
May contain:
end work zone sign: usually 500' past last device
downstream taper = 50'-100' per lane
Recommended Advanced Warning Sign Spaceing: Urban (low speed) CORRECT ANSWER 100'
Recommended Advanced Warning Sign Spaceing: urban (high speed) CORRECT ANSWER 350'
Recommended Advanced Warning Sign Spaceing: Rural CORRECT ANSWER 500'
