TC-12 Traffic Arrow Board - A Brief Overview

Traffic arrow boards and message boards play a crucial role in keeping the roadways and highways safe, alerting the motorists of diversions, lane changes, closures or other traffic-related updates. 

These electronic devices also help Utility workers and other crew working in traffic to safely conduct their operations during daytime or night, as they can appropriately alert motorists of the work ahead. One prominently-used arrow board is the TC-12 specification arrow board. The four basic modes of this arrow board and its general operating conditions will be examined below.

Overview of TC-12 traffic arrow board

Here are the 4 common operation modes of a TC-12 arrow board: 

Single arrow mode (right)

For stationary operations: Indicates that motorists need to switch to the right lane.
For mobile operations: If the board is mounted on a moving truck or utility vehicle, then motorists must keep their vehicles to the right.

Single arrow mode (left)

For stationary operations: Indicates that motorists need to switch to the left lane.
For mobile operations: If the board is mounted on a moving truck or utility vehicle, then motorists must keep their vehicles to the left.

Both Arrows Mode (Left and Right)

This mode should be used only in slow-moving traffic with speeds below 60km/h. It indicates that motorists must switch to either the right or left lane.

Bar Mode

This mode is only used on a utility vehicle that is operational in a closed lane or shoulder of the highway to make it conspicuous to other motorists.  

While these are basic operational modes of TC-12 arrow boards, their general application relies on a few conditions. 

Here are 4 situations where the use of the TC-12 arrow board is not warranted in Ontario province:

1. A Traffic Control Personnel Is Present

If a traffic control personnel is already directing and monitoring oncoming traffic, the arrow board might reduce the visibility of the personnel to motorists. Owing to this hazard, the use of traffic arrows is prohibited in this case. 

2. Automated Flagger Assistance Device (AFAD) Is Installed

An Automated Flagger Assistance Device (AFAD) is a unique traffic control device that displays automated flags to oncoming motorists. Thus, instead of multiple manual flaggers, traffic can be controlled with just one AFAD and single personnel who can safely operate it from a distance. In this scenario, a traffic board would be redundant. 

3. A Traffic Signal Is Present

The old-fashioned traffic signal is still adept at handling the influx of vehicles, especially in congested urban areas. A traffic arrow system would once again not be very useful in this scenario.

4. A Yield To Oncoming Traffic Sign Is Present

This sign denotes that motorists must give way to pedestrians and motorists coming from the opposite direction. Since compliance is mandatory and the sign is a constant fixture, it removes the need for installing traffic arrows.

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