ARC 2984C

ARC 2984C

TRANSPORTATION DEPARTMENT[761]

Adopted and Filed

Pursuant to the authority of Iowa Code sections 307.12, 307A.2 and 364.24, the Iowa Department of Transportation, on February 15, 2017, adopted amendments to Chapter 143, "Traffic Signal Synchronization," Iowa Administrative Code.

Notice of Intended Action for these amendments was published in the December 21, 2016, Iowa Administrative Bulletin as ARC 2863C.

The amendments add an adaptive signal control system to the types of coordinated traffic signal systems listed within rule 761—143.1(364) and make a coordinating change within subrule 143.4(1). The addition of the latest, most current method of traffic signal coordination will ensure that the rules are updated to current technology.

These rules do not provide for waivers. Any person who believes that the person's circumstances meet the statutory criteria for a waiver may petition the Department for a waiver under 761—Chapter 11.

These amendments are identical to those published under Notice of Intended Action.

After analysis and review of this rule making, no impact on jobs has been found.

These amendments are intended to implement Iowa Code section 364.24.

These amendments will become effective April 19, 2017.

The following amendments are adopted.

Item 1. Amend rule 761—143.1(364), definition of "Traffic signal system," as follows:

"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.

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

2. 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.

3. 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.

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

5. 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.

Item 2. Amend subrule 143.4(1) as follows:

143.4(1) Unless a traffic engineering study documents that it is not practical, traffic signals within one-half mile of each other along an arterial street or in a network of intersecting arterial streets shall be operated in coordination; preferably in a computerized, interconnected master-controlled, time-based coordinated, or traffic responsive system as a traffic signal system.

[Filed 2/15/17, effective 4/19/17]

[Published 3/15/17]

Editor's Note: For replacement pages for IAC, see IAC Supplement 3/15/17.