Traffic Control
The device that assigns right-of-way at an intersection using red, yellow, and green indications.
What is a traffic signal?
The term for the number of vehicles passing a point per unit of time.
What is traffic flow/volume?
This part of the roadway is intended for vehicle travel.
What is a travel lane?
This color indicates that drivers must stop.
What is red?
This color separates opposing streams of traffic.
What is yellow?
The type of intersection control requiring drivers to stop on all approaches.
What is all way stop control (AWSC)?
The number of vehicles occupying a unit length of roadway.
What is density?
This feature is the raised or painted area separating opposing traffic streams.
What is a median?
This signal indication warns that the green phase is ending.
What is yellow/amber?
This pavement marking indicates where a vehicle must come to a complete stop at a controlled roadway segment.
What is a stop bar/line?
The term for an area where two traffic streams merge, diverge, or cross.
What is a conflict point?
This is the equation representing the fundamental relationship among flow, speed, and density.
What is the equation q = uk ?
This roadway feature provides a gradual transition in elevation.
What is a vertical curve?
This term describes the inefficiency of vehicle movements as signal phases change.
What is lost time?
The full title of the document detailing standards for traffic control devices across the US.
What is the Manual on Uniform Traffic Control Devices?
A type of control adjusts signal timing in response to traffic conditions, typically via a loop detector.
What is actuated signal control?
This term is the maximum sustainable flow rate under specified roadway and traffic conditions.
What is capacity?
This technical term represents the banking of a roadway on a horizontal curve.
What is superelevation?
The technical term for a signal phase timing plan when a movement is permitted.
What is the green interval?
This pattern, typically found painted in white on British roads, are used to indicate pedestrian crossings and prohibit parking and overtaking.
What is a zigzag pattern?
This is the term for the point where vehicles must choose between competing paths through an intersection.
What is a decision point?
This term describes the traffic-flow condition that occurs when demand exceeds the available capacity.
What is oversaturation/what is oversaturated flow?
These two types of speed are used to guide roadway design.
What are design and target speeds?
This time, in seconds, is the absolute minimum green interval time dedicated to pedestrain crossing, according to the MUTCD.
What is 7 seconds?
One of two colors not in use by the MUTCD, and specifically stated as "reserved for future use."
What is coral/light blue?