3/25/26, 2:59 PM
ATSSA TRAFFIC CONTROL SUPERVISOR RE-
CERTIFICATION (MISSING SOME BASICS)
Formula for Min. taper length L=(WS²)/60 for 40MPH or less,
L=WS for 45MPH or more
speed used in formulas should be The off peak 85th percentile. Which is the speed at or below which 85% of vehicles travel
operating speed in free flow conditions
Distance of L for 25 MPH with 12' Lane width 125'
Distance of L for 35 MPH with 12' Lane width 245'
Distance of L for 45 MPH with 12' Lane width 540'
Distance of L for 55 MPH with 12' Lane width 660'
1/7
, 3/25/26, 2:59 PM
Distance of L for 65 MPH 12' Lane width 780'
Merging Taper Length L Minimum
Shifting Taper Length 1/2 L Minimum
Shoulder Taper Length 1/3 L Minimum
One-Lane, Two-Way Taper (Flagger taper) Length and number 50'-100' regardless of speed
of devices 6 devices 10'-20' apart
Downstream taper Length 50'-100' per lane
Tangent distance (between tapers) 2L
Tangent distance before shifting taper 1/2L
Activity Area Sub-components (3) Buffer Space
Work Space
Traffic Space
Longitudinal Buffer Space 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: 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
can contain: (2) zone sign
May contain:
end work zone sign: usually 500' past last device
downstream taper = 50'-100' per lane
2/7
ATSSA TRAFFIC CONTROL SUPERVISOR RE-
CERTIFICATION (MISSING SOME BASICS)
Formula for Min. taper length L=(WS²)/60 for 40MPH or less,
L=WS for 45MPH or more
speed used in formulas should be The off peak 85th percentile. Which is the speed at or below which 85% of vehicles travel
operating speed in free flow conditions
Distance of L for 25 MPH with 12' Lane width 125'
Distance of L for 35 MPH with 12' Lane width 245'
Distance of L for 45 MPH with 12' Lane width 540'
Distance of L for 55 MPH with 12' Lane width 660'
1/7
, 3/25/26, 2:59 PM
Distance of L for 65 MPH 12' Lane width 780'
Merging Taper Length L Minimum
Shifting Taper Length 1/2 L Minimum
Shoulder Taper Length 1/3 L Minimum
One-Lane, Two-Way Taper (Flagger taper) Length and number 50'-100' regardless of speed
of devices 6 devices 10'-20' apart
Downstream taper Length 50'-100' per lane
Tangent distance (between tapers) 2L
Tangent distance before shifting taper 1/2L
Activity Area Sub-components (3) Buffer Space
Work Space
Traffic Space
Longitudinal Buffer Space 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: 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
can contain: (2) zone sign
May contain:
end work zone sign: usually 500' past last device
downstream taper = 50'-100' per lane
2/7
