Written by: Ajay Kaushik 


After watching the video of a dump truck pushing a Mini Cooper up the on-ramp of the Gardiner Expressway in March of this year, I am personally very careful when driving around construction trucks. Transportation Canada statistics show that trucks, buses, and other large vehicles have been responsible for approximately 6-8% fatal accidents in Canada every year since 2000.

It is great to see that the general trend is showing a slow decline of fatal collisions in Canada. However, it is interesting to note that the fatal collision percentage increases to 2% from an average of less than 1% when trucks or large vehicles are involved in a collision.

Provincial governments have taken several steps to ensure that fatal collisions involving trucks and other large vehicles can be reduced through better infrastructure design, training and education of drivers, and installation of appropriate warning systems.

In this blog we highlight different types of warning systems installed to reduce chances of near misses and collisions with trucks on roadways.

Ontario’s TC-31A – Truck Entrance and Exit Warning System

Ontario Traffic Manual – Book 7 describes how a TC31A warning system should work:  “where the presence of a truck that is about to enter the road is automatically detected, the TC-31A sign may be used, with two amber flashers, one on each side of the sign, alternating in a ‘side to side’ manner, activated by the detector, so that the amber flashers provide a positive signal to motorists that a truck is about to enter the road”.

At Stinson ITS, we have designed a 100% solar powered TC-31A system which detects trucks using a microwave sensor, transmits the presence of a truck using approved 900MHz radio frequency which then triggers alternate flashing of 12” amber beacons to warn road users. As recommended by OTM Book 7, a TC-20At “WHEN FLASHING” sign is used to ensure road users are aware that the system only flashes when a truck is detected.  Ensuring increased compliance when a warning is provided.

Although provincial highway authorities mandate the use of such warning systems on almost all major construction zones, we often see contractors misunderstanding the system and installing cheaper 24 X 7 flashing signs. Using 24×7 flashing beacons with a TC-31A system is very inappropriate and can be misleading to road users as it contradicts the entire purpose of of the “when flashing” sign.  As drivers learn that the beacons never stop flashing they will inevitably lose trust in the warnings the system is intended to provide and likely begin ignoring it entirely over time.  .

We have seen the deployment of sub-standard TC-31A systems like this for many years now and it is frustrating, as they become essentially useless.  One might as well just put a static TC-31 sign with no “when flashing” sign, it would actually be more useful as at least it’s not providing incorrect warnings constantly.  There appears to be a lack of enforcement/inspection to ensure they are deployed and operating properly.

Stinson ITS is a well-known provider of sensor activated TC-31A signs with proven the reliability and effective operation of the warning system over the past 5 years.  The 407 East extension project used our TC-31A systems extensively and that’s the only large construction project we’ve seen in the GTA actually implement these properly.  We also provide many customizable options for modern construction zones where trucks may enter and exit the roadway from multiple points and drivers driving in both directions may need to be warned about oncoming trucks on the roadway(multiple detectors and multiple warnings sign systems).

TC-31A with One Detector Station and 2 Flashing Stations

TC-31A with Two Detector Stations and 2 Flashing Stations

Options are available to extend the distance for radio communications between detector and flashing stations for up to 300 meters. These systems have a sizeable road presence and can be visible to road users from 700-800 meters distance.

Other Truck warning System Applications We have also recently seen an increase in interest in custom applications for automated truck warning systems. We have proposed solutions near private construction sites, mining sites, and warehouses with high truck volumes to ensure road users are warned about oncoming truck traffic.

One such interesting example was from a municipality in Northern Ontario, where they wanted to warn drivers on a high-speed highway about trucks exiting a construction site. As shown in the image below, the municipality was interested in detecting only trucks in detection zone 1 and detection zone 2 (left turning vehicles)

in this case we designed a camera-based system to detect only when trucks are in zones 1 and 2 which would then activate the warning signs on both sides of the roadway as shown in the image below.


Trucks and other large vehicles, due to their larger turning radius and slower speeds, can present a serious danger to other road vehicles, especially when exiting or entering a roadway. A well designed warning system reduces the likelihood of severe collisions and helps save lives. At Stinson ITS, we are proud to offer in-house development of these systems and hope to see further adoption and use of them on our roads.


Check out our webinar “TC-31A Automated Truck Entrance and Exit Warning Systems”  hosted by Sheri Rowell & Ajay Kaushik.

In this Webinar, Stinson ITS’s Sheri Rowell, Account Manager – Western Canada, and Ajay Kaushik, Technical Sales Director, will discuss:
1. Where such systems should be deployed
2. Important design aspects when deploying the right system for a site and
3. Share interesting examples of TC-31A deployments in Canada.