IRD polishes WiM’s green credentials

A project in Canada is proving that Weigh in Motion can have a positive environmental impact, by helping to reduce emissions. Adam Hill looks at International Road Dynamics’ numbers
Classification & Data Collection / December 21, 2020 4 mins Read
By Adam Hill
WiM sensors at Alex Fraser Bridge, Highway 91 Southbound
WiM sensors at Alex Fraser Bridge, Highway 91 Southbound

Weigh in Motion (WiM) systems have many virtues for transportation agencies all over the world – but WiM’s potential to help drive environmental objectives is not often mentioned. Yet the green agenda is undoubtedly there. Take weigh station preclearance programmes, for instance. Efficiency is one good reason for adopting them. But Rod Klashinsky, ITS Solutions Advisor at International Road Dynamics (IRD), suggests that there is another.

“These technologies provide immense assistance to agencies that would otherwise struggle to carry out all the commercial vehicle weight and safety inspections with the resources available to them,” Klashinsky points out in a blog post. “However, there is another major reason for adopting preclearance programmes: reducing carbon emissions from commercial vehicles.”

IRD was able to put some figures on this in a contract in the west of Canada.

The Government of British Columbia (BC)’s Commercial Vehicle Safety and Enforcement (CVSE) agency put an emphasis on reducing emissions as part of its preclearance programme.

IRD was brought on board in 2007 by the British Columbia Ministry of Transportation and Infrastructure to supply technology for the Weigh2GoBC programme.

The system uses IRD’s iSINC WiM electronics at the roadside to control the scales, sensors, cameras, dedicated short-range communications (DSRC) antennae to read vehicle ID transponders, WiM scales and other in-road sensors used to weigh and screen vehicles. In addition, IRD provides system integration and software development for this province-wide e-Screening system, as well as ongoing maintenance.

Weigh2GoBC savings

Total number of encounters 6,922,266
Number of red lights 1,604,315
Number of green lights 2,702,066
Vehicle cost and time savings $ 43,179,014.68
Fuel savings $ 2,702,066.00
GHG emission savings $ 81,061.98
Total savings $ 45,962,142.66
GHG kg saving 3,026,313.92

In essence, Weigh2GoBC – which has won an innovation award from ITS Canada - is designed to reduce greenhouse gas (GHG) emissions while accelerating the flow of goods through the Pacific trade corridor.

“When a vehicle equipped with a Weigh2GoBC transponder passes a WiM-enabled station at highway speed, Weigh2GoBC checks the vehicle dimensions, weight and compliance with specific BC regulations electronically and signals the driver to proceed or check-in for inspection,” Klashinsky explains.

“Once a commercial vehicle has entered a Weigh2GoBC corridor, it can be given a bypass at all subsequent inspection stations for the next 24 hours.”


These bypasses are the key to cleaner air: they reduce the time which a heavy truck would otherwise be required to spend with engine idling at a weigh station.

“The more trucks that are lined up in a queue waiting to be weighed, the longer each vehicle is delayed as it waits for the queue to clear,” says Klashinsky. “Each litre of diesel fuel produces 2.66 kg of CO2e (carbon dioxide equivalent). Commercial vehicles also produce other emissions, such as volatile organic compounds (VOCs), carbon monoxide (CO), and oxides of nitrogen (NOX), known to contribute towards air pollution and smog.”

Figures suggest that heavy trucks are responsible for 15% of emissions in British Columbia - 8.9 million tonnes per year – so anything that puts a dent in that is potentially a major contributor to improved air quality.

For each bypass, approximately 1.12kg of GHG is saved. Heavy vehicles use 3-4 litres of diesel for each hour of idling. As each bypass saves 10 minutes of idling, on average, the estimate is derived from 0.6 litres of fuel per bypass (see Weigh2GoBC savings).

Weigh2GoBC has been expanded, too. The Alex Fraser Bridge and Nordel weigh station – the newest in the system – are prone to congestion, which bypasses are designed to ease.

Six lanes of WiM have been added on the southbound approach to the bridge, with WIM lanes at the north end for vehicles heading south from Richmond, New Westminster and Annacis Island.

Vehicles are screened and directed to pull into the weigh station by a red light activation on the vehicle transponder; if they get a green light, the Weigh2GoBC member vehicle can continue on its way without stopping.

All other non-Weigh2GoBC commercial trucks are directed to pull into the Nordel station for further inspection and weighing. If they do not comply, they are identified by camera for enforcement follow-up – including by possible inspection and weighing portable scales further up the road.

The question of data-sharing is a crucial one: British Columbia has an agreement with the US state of Washington, just over the border, which allows “automated bypass benefits for trucks in both jurisdictions”, Klashinsky says.

Cross Zlin in Uganda

Cross Zlin is to install three high-speed WiM systems at sites in Uganda as part of a deal with the Uganda National Roads Authority (UNRA), which is in charge of road management in the east African country. In addition to the development of the road network, modernisation of traffic systems is among the main aims of UNRA, with WiM an important part of this. In congested areas around the urban centres of Magamaga, Luwero and Mbarara, Cross Zlin has manufactured and supplied the WiM equipment, which includes a system for diverting vehicles to checkpoints.   

Overloaded vehicles will be accurately detected and diverted to weighing points - the aim is to cut the wear on busy roads and ensure that they last longer. The company says the project takes in production, transport, installation and testing of the entire system, and includes 3D monitoring of vehicles, detection of double assemblies and ANPR cameras.

Kistler in Ohio

Pulling together accurate traffic data collection has been a focus for Ohio Department of Transportation (ODoT), and the agency has a partnership with WiM specialist Kistler to help on exactly this.

“Acquiring precise traffic data is very important for us because allocation of Federal budget funds depends on those statistics,” explains Dave Gardner, manager of ODoT’s Traffic Monitoring Section. “Axle loads and overall truck weights are recorded and submitted for the Federal Data Plan.”

ODoT has 22 WiM stations to monitor stress on Ohio’s roads caused by trucks and heavy commercial vehicles. “We’ll gradually be adding more installations in the coming years,” says ODoT field manager Sandie Mapel. “We believe it’s very important to deploy the correct systems in terms of installation, operation and data quality.”

The agency installed a WiM test section on US Route 23, which crosses Ohio from north to south, equipped with quartz-based Lineas sensors from Kistler. Mapel was impressed with their data quality, as well as the ease with which they could be installed in existing roads. ODoT has pledged to deploy more Kistler sensor technology to acquire traffic information and is examining how much use it could make of the complete KiTraffic Statistics system. The agency says it plans to set up another test section to assess this.

The company’s first Lineas deployment in Ohio was back in 2007 – and a Kistler installation from 2011 is still operating in the state today.

The state has no plans yet to increase its WiM applications to take in direct enforcement.

“We aren’t there yet,” says Gardner. “Law enforcement carry out random checks on trucks, and we also send them traffic monitoring data for analysis purposes. But the data isn’t forwarded to law enforcement in real time.”

But when it comes to using WiM for bridge- overload protection, for example, there might be more scope, thinks Kistler. The firm says Ohio has the second-largest number of bridges of all US states “and many of them were built after the second world war, so they require appropriate monitoring, protection and maintenance”.

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