Iowa Admin. Code r. 761-143.1

Current through Register Vol. 47, No. 8, October 30, 2024

Rule 761-143.1 - Definitions

The following definitions apply to these rules:

"Arterial street" means any U. S. or state numbered route, controlled access highway, or other major street or highway designated by the city within its respective jurisdiction as a part of a major arterial system of streets or highways.

"Controller" means a supervisory device that controls the sequence and duration of indications displayed by traffic signals.

"Coordination " means the establishment of a definite timing relationship between adjacent traffic signals.

"Cycle" means any complete sequence of traffic signal indications (phases).

"Detector " means a device that senses vehicular or pedestrian demand and transmits an impulse to a controller.

"Local controller " means a controller supervising the operation of traffic signals at a single or two closely spaced intersections.

"Master controller" means a controller supervising the operation of several local controllers.

"Phase " means a portion of the cycle during which an assignment of right-of-way is made to a traffic movement or combination of traffic movements.

"Traffic signal" means any permanently installed, electrically powered traffic control device by which traffic is alternately directed to stop and to proceed.

"Traffic signal system " means two or more traffic signals operating in a coordinated manner. Types of coordinated systems:

1."Adaptive signal control system" means a system in which traffic signals across a signal network are coordinated by adjusting the lengths of signal phases based on prevailing traffic conditions.

2."Computerized system " means a system in which controllers are supervised by a computer.

3."Interconnected master-controlled system" means a system in which local controllers are supervised by a master controller through a communications link (wire/radio). The master establishes a base line condition; the local then operates its intersection in a predetermined relationship with the base line.

4."Noninterconnected system" means a system in which timing relationships between individual local controllers are coordinated by manual settings, without physical interconnection between the controllers.

5."Time-based coordinated system" means a noninterconnected system in which the local controllers use a programmable digital timing and control device (time-based coordinator) to maintain coordination.

6."Traffic responsive system " means a system in which a master controller specifies cycle timings based on the real time demands of traffic as sensed by vehicle detectors.

Iowa Admin. Code r. 761-143.1

Amended by IAB March 15, 2017/Volume XXXIX, Number 19, effective 4/19/2017