ATSSA TCS Modules 3 Parts of TTC
Zone & 4 TTC Devices EXAM WITH
CORRECT ANSWERS
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 the
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 conditions. 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 distance allows drivers to adjust
to one condition before moving to another one. Two cases: 1) Merging taper
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 residential= 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.
Zone & 4 TTC Devices EXAM WITH
CORRECT ANSWERS
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 the
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 conditions. 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 distance allows drivers to adjust
to one condition before moving to another one. Two cases: 1) Merging taper
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 residential= 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.
