VERIFIED SOLUTION
High-Traffic Areas - High-volume streets, such as arterials. Typically wide and have
multiple lanes of travel.
Low-Traffic Areas - Low-volume streets such as local streets or collector streets.
Typically narrow and have single lanes of travel.
Insulated Hand Tools - Tools with insulated handles, designed to protect from electric
shock when working with live electricity.
Insulated Mats/Blankets - Safe place to stand when working on electric systrems
Circuit Breaker Finders - Tool that helps locate the appropriate circuit breaker or fuse
that controls the electrical supply to the area.
Conductors - Materials that conduct electricity
Ex. Most metals
Insulators - Materials that do not conduct electricity
EX. plastic, rubber, glass, ceramic
Understanding electricity - Electricity is similar as water flowing through pipes
Voltage is like water pressure.
Current is like amount of water.
Resistance is like the size of the pipe.
Ohm's Law - E = I x R
E = Voltage(Electromotive Force) (Volts)
I = Current(Intensity) (Amps)
R = Resistance (Ohms)
120 VAC/ 24 VDC - Typical voltages used in traffic signal circuits
Alternating Current - The electrons flow in a switching direction going forward and
backwards. In a power grid usually 120 Volts at 60 cycles per second(Hertz)
EX.Powers homes, businesses, factories
, Direct Current - electrons flow in one direction
5, 12, 24 Volts usually
EX. Batteries, power supplies
Bonding and grounding - Joining metallic parts and using them to provide an electrically
conductive path to the ground
Phases - Through phases are typically even numbered and left turn phases are odd
numbered. Phases 1- 2- 5- 6 are the main street, while 3 -4 - 7 -8 are the side street
Concurrent group - phases that are grouped on the same street. phases usually turn on
with the the others in their group. divided by barrier, e.g main street/ side street
Ring - identifies phases that may operate one after another. organizing conflicting
phases such as a left turn not being on while through is on the opposite way.
Barrier - Separates opposing phases to avoid conflicting movements at the same time.
Also helps in rings relationship
Protected Phases - Provide exclusive right-of-way to a specific movement, allowing
passage with no conflicting traffic
Permissive Phases - Allow movement to proceed with caution when there is a gap in
conflicting traffic. Usually yielding or giving right of way to crossing traffic
Calculating signal intervals - Turning movement counts - data on traffic volume
Signal phasing- data on terrain
Minimum green time- time to clear intersection
Pedestrian clear time
Yellow & All-Red Intervals
Coordination & Optimization
Split - Allocation of time within a single cycle for a specific movement or phase. it
represent the duration or percentage
Offset - time difference between the initiation of signal phases or intersections along a
corridor. Effective offset can help reduce stops, improve travel times, enhance fuel
efficiency
Lead Left-Turns - protected left-turn served prior to the complementary through
movement. most common
Lag Left-Turns - Protected left turn served after the complementary through movement.
most used in coordinated systems with closely spaced lag left turn intersections such as
diamond interchanges