ATSSA TCS MODULES 3 PARTS OF TTC ZONE &
4 TTC DEVICES QUESTIONS WITH CORRECT
ANSWERS 2025
Roundabouts - CORRECT ANSWER -
Not in MUTCS. Consider detours. If single lane, treat as flagger operation. Getting popular
Speed - CORRECT ANSWER -Posted speed=speed limit (min) Off-
peak 85th percentile speed prior to work starting or the anticipated operating speed. Not necessarily t
he posted speed
85th percentile speed - CORRECT ANSWER -
The speed at or below which 85 percent of the motor vehicles travel operating speed in free flow con
ditions. Often 7-8 mph above posted speed
Multiple tapers - CORRECT ANSWER -
If more than one taper is needed, they should be separated by a tangent (transition) distance. This dis
tance allows drivers to adjust to one condition before moving to another one. Two cases: 1) Merging t
aper followed by a second merging taper -2L
2) Merging taper followed by a shifting taper - 1/2L
Signs clearances - CORRECT ANSWER -
Clearances: 1) Rural=5ft min. with advisory speed plaque=4 ft. min.2) Business, commercial and reside
ntial= 7 ft.
Signs colors and sizes - CORRECT ANSWER -13 colors most common -
For conventional road= the majority of the signs measure 30 x 30, 36 x36, 24 x 18, 24 x 12 and Road
closed 48 x30
Arrow boards - CORRECT ANSWER -
Are a supplemental device used in addition to signs, barricades or other TC devices. Type C board for
high-
speed facilities (1 mile visibility), 50% dimming at night. Locate on shoulder at beginning of taper. If no
room place it inside taper behind channelizing devices, as close to the merging point as possible. Do
not use on a two-lane, two-way roadway for temporary one-lane operation nor for on lane shifts.
4 TTC DEVICES QUESTIONS WITH CORRECT
ANSWERS 2025
Roundabouts - CORRECT ANSWER -
Not in MUTCS. Consider detours. If single lane, treat as flagger operation. Getting popular
Speed - CORRECT ANSWER -Posted speed=speed limit (min) Off-
peak 85th percentile speed prior to work starting or the anticipated operating speed. Not necessarily t
he posted speed
85th percentile speed - CORRECT ANSWER -
The speed at or below which 85 percent of the motor vehicles travel operating speed in free flow con
ditions. Often 7-8 mph above posted speed
Multiple tapers - CORRECT ANSWER -
If more than one taper is needed, they should be separated by a tangent (transition) distance. This dis
tance allows drivers to adjust to one condition before moving to another one. Two cases: 1) Merging t
aper followed by a second merging taper -2L
2) Merging taper followed by a shifting taper - 1/2L
Signs clearances - CORRECT ANSWER -
Clearances: 1) Rural=5ft min. with advisory speed plaque=4 ft. min.2) Business, commercial and reside
ntial= 7 ft.
Signs colors and sizes - CORRECT ANSWER -13 colors most common -
For conventional road= the majority of the signs measure 30 x 30, 36 x36, 24 x 18, 24 x 12 and Road
closed 48 x30
Arrow boards - CORRECT ANSWER -
Are a supplemental device used in addition to signs, barricades or other TC devices. Type C board for
high-
speed facilities (1 mile visibility), 50% dimming at night. Locate on shoulder at beginning of taper. If no
room place it inside taper behind channelizing devices, as close to the merging point as possible. Do
not use on a two-lane, two-way roadway for temporary one-lane operation nor for on lane shifts.
