5 Control Equipment

Controller assemblies can be either Type 170 controllers or National Electrical Manufacturers Association (NEMA) controllers with dual ring; eight vehicle phase, four pedestrian phase, four overlap, operational capabilities. From a design perspective, identical operation can be obtained from either controller. Specify the Type 170 unless the region's policy is to use NEMA controllers.

In situations where it is necessary to coordinate the traffic movements with another agency, it is necessary for one of the agencies to be responsible for the operation of the traffic signal, regardless of which agency actually owns and maintains the signal. This is accomplished by negotiating an agreement with the other agency. At a new intersection, where the state owns the signal but another agency has agreed to operate the signal, the controller must be compatible with that agency's system.

When Type 170 controllers are used, but it is necessary to coordinate the state owned and operated signals with another jurisdiction's system using NEMA controllers, use compatible NEMA controllers installed in Type 170/332 cabinets. Specify a C1 plug connected to a NEMA A, B, C, and D plug adapter for these installations. The Model 210 conflict monitor in the Type 170/332 cabinet can be used with a NEMA controller by changing a switch setting. The Type 12 NEMA conflict monitor is not used in this configuration. It does not fit in a Type 170/332 cabinet and the operation is not compatible. When a NEMA cabinet is used, specify rack-mountings for the loop detector amplifiers and the preemption discriminators.

Coordinate with the region's electronics technician to determine the optimum controller cabinet location and the cabinet door orientation. The controller cabinet is positioned to provide maintenance personnel access. At this location, a clear view of the intersection is desirable. Avoid placing the controller at locations where it might block the view of approaching traffic for a motorist turning right on red. Avoid locating the controller where flooding might occur or where the cabinet might be hit by errant vehicles. If possible, position the controller where it will not be affected by future highway construction.

If a telephone line connection is desired for remote signal monitoring and timing adjustments by signal operations personnel, provide a modem in the controller cabinet and separate conduits and a junction box between the cabinet and the telephone line access point.

Vehicle and pedestrian movements are standardized to provide uniformity in signal phase numbering, signal display numbering, preemption channel identification, detection numbering, and circuit identification. The following are general guidelines for the numbering system:

• Assign phases 2 and 6 to the major street through movements, orienting phase 2 to the northbound or eastbound direction of the major street.

• Assign phases 1 and 5 to the major street protected left-turn movements.

• Assign phases 4 and 8 to the minor street through movements.

• Assign phases 3 and 7 to the minor street protected left-turn movements.

• At "Tee" intersections, assign the movement on the stem of the "Tee" to either phase 4 or phase 8.

• At intersections with four approaches and each minor street times separately, assign the minor streets as phase 4 and 8 and note on the phase diagram that these phases time exclusively.

• Signal displays are numbered with the first number indicating the signal phase. Signal displays for phase 2, for example, are numbered 21, 22, 23,and so on. If the display is an overlap, the designation is the letter assigned to that overlap. If the display is protected/permissive, the display is numbered with the phase number of the through display followed by the phase number of the left-turn phase. A protected/permissive signal display for phase 1 (the left-turn movement) and phase 6 (the compatible through movement), for example, is numbered 61/11. The circular red, yellow, green displays are connected to the phase 6 controller output and the yellow and green arrow displays are connected to the phase 1 controller output.

• Pedestrian displays and detectors are numbered with the first number indicating the signal phase and the second number as either an 8 or 9. Pedestrian displays and detectors 28 and 29, for example, are assigned to phase 2.

• Detection is numbered with the first number representing the phase. Detection loops for phase 2 detectors are numbered 21, 22, 23, and so on.

• Emergency vehicle detectors are designated by letters; phase 2 plus phase 5 operation uses the letter "A", phase 4 plus phase 7 uses the letter "B", phase 1 plus phase 6 uses the letter "C", and phase 3 plus phase 8 uses the letter "D".

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