ATSSA TRAFFIC CONTROL SUPERVISOR RE-CERTIFICATION TEST
RECENTLY UPDATED 2026
ANSWER Formula for Minimum Taper Length: L=(WS²)/60 for 40 mph or
less, L=WS for 45 mph or more
the 85th percentile off peak. Which speed, when running in free flow
conditions, is reached by 85% of vehicles? The ANSWER speed used in
formulae should be
125' is the ANSWER distance of L at 25 mph and a lane width of 12'.
245'- ANSWER Distance of L at 12' Lane Width and 35 MPH
L's ANSWER distance at 45 mph with a 12-foot lane width is 540'.
L's ANSWER distance at 55 mph with a 12-foot lane width is 660'.
L's response distance at 65 mph (12' lane width) is 780'.
ANSWER Merging Taper Length L Minimum
ANSWER Shifting Taper Length: 1/2 L Minimum
ANSWER Shoulder Taper Length: 1/3 L Minimum
50' to 100' at any speed
ANSWER One-Lane, Two-Way Taper (Flagger taper) with six devices spaced
10'-20' apart Number and length of devices
ANSWER : Length of downstream taper: 50' to 100' per lane
The tangent distance (between tapers) is 2L.
ANSWER Tangent distance prior to shifting taper: 1/2L
The buffer space
Work Area
Sub-components of the Traffic Space- ANSWER Activity Area (3)
, Forgiving design for the recovery area for errant cars
safeguards drivers and employees
Always totally clear or vacant
No trucks, attenuators on trucks, tools, or supplies
ANSWER Longitudinal Buffer Space is strongly advised, unless there is a
demonstrated reason not to.
Road users are redirected to their usual route from the work area's downstream
end to the last device, such as the end work zone sign.
ANSWER Termination Area: May include: End work zone sign: typically 500'
past last device downstream taper = 50'-100' per lane
can include: (2)
ANSWER : Urban (low speed) is the recommended advanced warning sign
spacing of 100'.
The recommended advanced warning sign spacing for metropolitan areas (high
speed) is 350 feet.
Rural Advanced Warning Sign Spacement Recommendation: 500'
The recommended advanced warning sign spacing for freeways and
expressways is 1000', 1500', and 2640' (3).
If at all possible, start the taper at the 1 mile 50% shoulder; if not, start as close
to the taper's beginning as you can. ANSWER The arrow board's visibility
distance is intentionally dimmed at night.
Where:
taper: not going over the posted speed limit in feet
tangent: ANSWER device spacing taper = twice posted speed limit - distance
Tangent:
A: Flashing at low intensity
B: Flashing at a high intensity
C: Constant Burn
D: ANSWER Warning light types: 360° steady burn
Kind A: Kind B: Kind C: Kind D:
Applications for portable changeable message signs PCMS- ANSWER speed
decreases, notable delays, and unfavorable circumstances
RECENTLY UPDATED 2026
ANSWER Formula for Minimum Taper Length: L=(WS²)/60 for 40 mph or
less, L=WS for 45 mph or more
the 85th percentile off peak. Which speed, when running in free flow
conditions, is reached by 85% of vehicles? The ANSWER speed used in
formulae should be
125' is the ANSWER distance of L at 25 mph and a lane width of 12'.
245'- ANSWER Distance of L at 12' Lane Width and 35 MPH
L's ANSWER distance at 45 mph with a 12-foot lane width is 540'.
L's ANSWER distance at 55 mph with a 12-foot lane width is 660'.
L's response distance at 65 mph (12' lane width) is 780'.
ANSWER Merging Taper Length L Minimum
ANSWER Shifting Taper Length: 1/2 L Minimum
ANSWER Shoulder Taper Length: 1/3 L Minimum
50' to 100' at any speed
ANSWER One-Lane, Two-Way Taper (Flagger taper) with six devices spaced
10'-20' apart Number and length of devices
ANSWER : Length of downstream taper: 50' to 100' per lane
The tangent distance (between tapers) is 2L.
ANSWER Tangent distance prior to shifting taper: 1/2L
The buffer space
Work Area
Sub-components of the Traffic Space- ANSWER Activity Area (3)
, Forgiving design for the recovery area for errant cars
safeguards drivers and employees
Always totally clear or vacant
No trucks, attenuators on trucks, tools, or supplies
ANSWER Longitudinal Buffer Space is strongly advised, unless there is a
demonstrated reason not to.
Road users are redirected to their usual route from the work area's downstream
end to the last device, such as the end work zone sign.
ANSWER Termination Area: May include: End work zone sign: typically 500'
past last device downstream taper = 50'-100' per lane
can include: (2)
ANSWER : Urban (low speed) is the recommended advanced warning sign
spacing of 100'.
The recommended advanced warning sign spacing for metropolitan areas (high
speed) is 350 feet.
Rural Advanced Warning Sign Spacement Recommendation: 500'
The recommended advanced warning sign spacing for freeways and
expressways is 1000', 1500', and 2640' (3).
If at all possible, start the taper at the 1 mile 50% shoulder; if not, start as close
to the taper's beginning as you can. ANSWER The arrow board's visibility
distance is intentionally dimmed at night.
Where:
taper: not going over the posted speed limit in feet
tangent: ANSWER device spacing taper = twice posted speed limit - distance
Tangent:
A: Flashing at low intensity
B: Flashing at a high intensity
C: Constant Burn
D: ANSWER Warning light types: 360° steady burn
Kind A: Kind B: Kind C: Kind D:
Applications for portable changeable message signs PCMS- ANSWER speed
decreases, notable delays, and unfavorable circumstances
