Weigh-In-Motion, What Does It Mean And What Does It Apply To?

At a glance

• Weigh-In-Motion (WIM) technology allows for the measurement of weights without the need for vehicles to stop, making it more efficient and reducing traffic congestion.
• WIM systems have applications in a variety of industries, including transportation, logistics, law enforcement, and mining.
• While there are challenges and limitations to WIM systems, their benefits make them a valuable tool for collecting traffic data, enforcing weight regulations, and protecting roads and bridges from damage caused by overweight vehicles.

 

Weigh-In-Motion (WIM) technology has revolutionised the way we measure and monitor traffic on roads and highways. WIM systems use sensors embedded in the pavement to record a vehicle’s weight as it travels over the sensor at normal speeds. With this data, transportation authorities can monitor traffic, enforce weight limits, and improve road safety. From freight operations to road maintenance, WIM is a critical tool for optimising our highways and keeping them safe for all motorists.

WIM is a cost-effective solution for weighing vehicles in motion, and it has significant implications for various industries, including transportation, logistics, and law enforcement. In this blog, you’ll get a comprehensive understanding of what WIM means, how it works, and its benefits and limitations. With the growing demand for efficient and accurate weighing systems, WIM has gained traction worldwide, and this blog aims to shed light on this critical technology.

Explanation of weigh-in-motion (WIM)

 

A weighbridge or scale is an essential piece of equipment for the day-to-day needs of many industries. Weighing large, heavy haul trucks and trains has become a lot easier for workers, with the help of innovations in weighing technology. Gone are the days when the only option was the manual entry of data and weighing. With the advances in technology throughout the weighing industry, all aspects of data collection and weighing have been taken to a new level. It’s now faster, more accurate and automatic.

In-Motion weighbridge systems are used to weigh vehicles while they are in motion. These systems usually consist of sensors installed on the road, which are capable of detecting the weight of the vehicle as it passes over them. This technology has been around for several decades and has seen widespread adoption in various transportation industries, including freight, logistics, and public transport. The primary aim of WIM systems is to collect data on vehicle weights and reduce the need for vehicles to stop and weigh in at specified checkpoints. This data can be used for enforcing gross vehicle weight regulations, ensuring road safety, and optimising logistics operations. WIM systems work by measuring the pressure or force exerted by the vehicle tires on the roadway, providing an accurate reading of the vehicle’s weight. There are different types of WIM systems available, including piezoelectric, fibre-optic, and bending plate systems.

History

 

Weigh-in-motion (WIM) originated in the early 1900s by measuring the dynamic tyre forces of moving vehicles to estimate their gross weight. The first operational WIM system was created in the Netherlands in the 1970s, measuring vertical forces from vehicle wheels on a sensor embedded in the road. Today’s WIM systems are sophisticated, using various sensors, cameras, and software to measure vehicle weight and other parameters. WIM is now used in transportation, logistics, law enforcement, and safety to improve efficiency, lower costs, and ensure compliance with legal weight limits.

Importance of WIM in various Industries

 

Weigh-in-Motion (WIM) technology is crucial in many industries due to its efficient and accurate weighing of moving vehicles. Transportation, logistics, law enforcement, safety, and construction sectors rely on WIM for accurate weight measurements to ensure vehicle balance, fuel economy, road safety, and infrastructure protection. WIM on railways detects overloaded trains and avoids excessive wear and tear on railway tracks. WIM’s accuracy and efficiency make it an integral part of various industries.

Understanding Weigh-In-Motion

 

WIM devices capture and record truck axle weights and gross vehicle weights while the vehicle is in motion. WIM scales can weigh vehicles at speed, without needing to stop. They use quartz piezo sensors to measure per-axle and gross weight of vehicles. The sensors measure the dynamic vertical forces of the vehicle to calculate the weight, and this weight data is transmitted in real-time to a computer system for analysis and reporting. Appreciating the technology behind WIM systems is critical in understanding their applications in industries such as transportation, logistics, law enforcement, and safety.

How WIM systems work?

 

Weigh-In-Motion (WIM) systems are used in transportation and logistics, agriculture, and law enforcement industries. WIM systems weigh vehicles while in motion, which is more efficient and less intrusive than traditional static weigh scales. WIM systems integrate multiple sensors, including strain gauges and piezoelectric sensors, to capture data on vehicle pressure and weight distribution. Collected data calculates the vehicle’s weight, speed, and other relevant metrics. Different types of WIM systems include high-speed, low-speed, and portable weigh-in-motion systems that use various measurement techniques, such as bending plate, load cell, and fibre optic sensors, for maximum accuracy and reliability.

Different types of WIM systems

 

There are different types of WIM systems based on the sensors they use to capture vehicle data. Some types include the piezoelectric sensor, strain gauge sensor, fibre-optic sensor, laser sensor, and radar sensor. Each type of sensor has its unique advantages and limitations. The piezoelectric sensor is commonly used in highways and airports and is known for its durability, while the fibre-optic sensor provides highly accurate weight measurements. The use of radar sensors is becoming popular in the railway industry. A proper understanding of these systems is essential for their successful application in monitoring various features of dynamic vehicles in motion.

Weigh-in-motion (WIM) systems are used to measure the weight of vehicles while they are in motion. There are several types of WIM systems available, each with its own unique features and applications.

• Static weighing systems are not WIM systems by definition, but they are often used as reference values when calibrating WIM systems. In many countries, static weighing systems are legally approved for direct enforcement or trade applications.
• Low speed WIM (LS-WIM) systems are designed to weigh vehicles in a controlled area, typically outside the main traffic lane, on a flat and smooth platform that is at least 30 meters long. The velocity and transverse movement of the passing vehicles are controlled in order to eliminate dynamic effects.
• High speed WIM (HS-WIM) systems weigh vehicles in the open traffic lanes at normal speed and under free flow conditions. The measurements are affected by the vehicle dynamics that depend on a combination of the road geometry, driving behaviour of the driver, and the reaction of the vehicle suspension. Good HS-WIM systems on smooth roads have an accuracy of between approx. ±5 to ±10% for gross vehicle weight (GVW) measurements.
• Bridge WIM (B-WIM) systems use sensors attached to the bottom side of beams or deck of a bridge, viaduct, or culvert to measure strains caused by the bending of the bridge when vehicles pass over it. B-WIM systems provide the same vehicle information as pavement WIM systems and can also collect valuable data about bridge behavior that can be used for safety assessments.
• Dynamic On-Board WIM (OBW) systems are fitted with vehicles to measure their GVW, axle, and wheel loads while they are moving. The typical measurement inaccuracy of OBW systems is between approx. ±1 and ±3%, depending on the sensing technology. The weight data can be combined with GPS location data and stored during travel. OBW systems are used to manage heavy vehicle operation and monitor compliance with access to certain parts of the road network.

Applications of Weigh-In-Motion

 

Weigh-in-motion (WIM) systems have diverse applications in several industries. WIM technology saves time in transportation and logistics by weighing all vehicles at full speed and directing only overweight ones for further inspection.

In railway transportation, WIM records the dynamic vertical forces exerted by railcars. WIM aids traffic enforcement by efficiently detecting overloaded vehicles on highways.

It plays a vital role in preventing premature deterioration of pavement and bridge structures caused by overweight vehicles. WIM technology is critical across multiple industries and can yield significant benefits when used appropriately.

Overview of industries that use WIM

 

Weigh-in-motion (WIM) technology is widely used across several industries due to its accuracy and efficiency in weight measurement. Transportation and logistics companies use WIM systems to monitor truck weights and avoid overloading, which can cause road and bridge damage. Law enforcement agencies rely on WIM systems to enforce weight regulations and ensure road safety. In agriculture, WIM technology is used to weigh transported produce, while the mining industry uses it to measure heavy truck loads. WIM technology is thus used in a variety of industries for collecting traffic data, enforcing weight regulations, and safeguarding infrastructure from overweight vehicles.

Trakblaze have developed an advanced range of weighing systems, known as weigh-in-motion weighing scales. Unlike traditional weighing systems, weigh-in-motion scales can weigh a vehicle while it is travelling at speed; the vehicle doesn’t need to stop completely to be weighed. It is an incredible and top-rated weighing solution for a range of industries around the world, who needs to weigh their road and rail vehicles.

Weigh-in-motion offers a cost-effective solution to organisations by monitoring the weight of vehicles as they travel over a railway line, roadway, or across a mining site. There are many benefits to a weigh-in-motion system, such as they increase productivity, efficiency, instant identification of overload, comprehensive reporting and these, are also very cost-effective.

Trakblaze PTY LTD manufactures two different types of weights in motion systems – Road/Mining weigh-in-motion and Rail weigh-in-motion – to meet the specific requirements of those particular vehicles and industries, while keeping roadways and railways safe.

Weigh-In-Motion – Railway

It is crucial that the rail wagons are safe and balanced before transportation. This is where you need to rely on train weighbridge scales and their data to ensure the wagons are safe. With over 90 years of experience in weighbridges, Trakblaze has developed a highly accurate and reliable weigh-in-motion solution for railways. This will allow trains to be weighed at a speed of up to 80kph, and then return accurate data.

Trakblaze offers two different weigh-in-motion solutions for railways – Infinity low speed and Infinity high speed.

Infinity Low Speed: This train weighbridge is ideal for weighing slow-speed trains (up to 15kph), especially in mining. With this, you can get wagon and bogie weight and data in real-time, and the best thing about it is, it can be installed even in a curved track.

Infinity High Speed: As the name suggests, it’s capable of weighing trains at a high speed (up to 80 kph). It uses highly reliable and accurate load cell technology, so you don’t have to worry about the data being inaccurate while weighing in such a high speed.

Weigh-In-Motion – Roadway/Mining

Similar to railways, Trakblaze offers a weigh-in-motion solution for roadways and mines.

Force 1 (Truck Axle Scale): A specially designed weigh-in-motion axle weighbridge to reduce the considerable space to install a traditional weighbridge. It is designed to record axle weights, and gross vehicle weights as trucks drive over the scale. Force 1 can provide highly accurate weighing data of a vehicle in motion up (dynamic) to 12Kph.

Force 2/4 (Portable Mining Truck Scales): The Force mining scales are ideal for all types of Mining Truck/Dump Truck In motion weighing applications. They can be installed as a short-term solution where the mine is constantly changing or permanently on established haul routes. With 2 differing options for truck size (Force 2 up to 150t/ Force 4 for over 150t) the Force mining options are built tough to last harsh working mine environments, while allowing in motion weighing at up to 12 kph by wheel, axle and truck.

Advantages and Challenges of Weigh-In-Motion

 

Advantages of Weigh-In-Motion

• Enhanced Efficiency: WIM systems allow for measurements to be taken while the vehicle is in motion, eliminating the need for cars and trucks to stop and pass over stationary scales. This results in fewer delays, enhanced efficiency, and reduced costs of the weighing process.
• Improved Road Safety: WIM systems are highly effective in preventing damage to pavements caused by overloaded trucks, resulting in improved road safety and lower maintenance costs for transportation authorities.
• Law Enforcement: WIM technology enables law enforcement agencies to identify and prosecute overweight and unsafe vehicles, ensuring compliance with weight regulations and enhancing road safety.
• Cost-Effective: Compared to traditional weighing methods, WIM technology is a cost-effective solution for industries that require continuous and accurate vehicle weighing.
• Real-Time Data Collection: WIM systems provide real-time weight data, allowing for immediate decision-making and timely responses to potential safety hazards.

Benefits of using WIM technology over traditional weighing systems

• Enables measurements to be taken while the vehicle is in motion, avoiding the need for cars and trucks to stop and pass over stationary scales.
• Translates to fewer delays, enhanced efficiency, and reduced costs of the weighing process.
• Highly effective in preventing damage to pavements caused by overloaded trucks, resulting in improved road safety and lower maintenance costs for transportation authorities.

Benefits of WIM for law enforcement and safety

• Allows for the identification and prosecution of overweight and unsafe vehicles, improving road safety.
• Reduces the time and cost associated with weighing vehicles, allowing for more efficient monitoring of vehicles.
• Provides real-time data for weight enforcement, enabling more effective enforcement of weight restrictions.

Challenges of Weigh-In-Motion

• Inaccurate Readings: Environmental factors, road conditions, or calibration errors can lead to inaccurate readings, affecting the reliability of WIM technology. Regular maintenance and calibration of WIM systems are crucial to ensure optimal performance and avoid errors.
• Installation Costs: The initial cost of installing a WIM system can be high, although it is a cost-effective long-term solution.
• Limited Accuracy: High-speed WIM systems have an accuracy of between ±5 to ±10% for Gross Vehicle Weight (GVW) measurements, which may not be suitable for some applications that require a higher degree of accuracy.

Advantages of using WIM over static scales

• Saves time and allows for a more efficient flow of traffic
• Provides dynamic axle weight measurements for a more accurate representation of the vehicle’s weight distribution
• Can weigh vehicles travelling at high speeds, making them useful in areas where traffic needs to be continuously monitored
• Can detect and alert authorities to overloaded vehicles in real-time, improving law enforcement and safety on the roads

Limitations and challenges of WIM systems

Weigh-in-Motion (WIM) systems offer several benefits for a range of industries, but they also come with certain limitations and challenges that need to be considered. Here are some of the key limitations and challenges of WIM systems:

Accuracy: One major challenge with WIM systems is the accuracy of weight measurements. External factors such as speed, temperature, and vehicle type can affect the measurement, leading to inaccurate results. The accuracy of the system can be affected by the design, construction, installation, and calibration of the WIM system.

Cost: WIM systems can be relatively expensive to install and maintain. The systems require a significant amount of infrastructure, including sensors, data processing systems, and communication networks, which can increase the cost of installation and maintenance.

Maintenance: WIM systems require regular maintenance to stay operational. The systems are exposed to harsh environmental conditions, including temperature changes, moisture, and debris, which can damage the sensors and affect the accuracy of the measurements.

Vehicle types and loads: WIM systems may not be suitable for all types of vehicles and loads. The size, weight, and shape of the vehicle can affect the accuracy of the measurement, and certain types of loads, such as those with irregular shapes, may not be accurately measured by WIM systems.

Legal issues: There may be legal issues associated with the use of WIM systems, such as data privacy and security concerns, liability issues, and the need for certification and standardisation.