Weight to go

from Intertraffic World 2018

Last word

Weigh-in-motion sensors contribute vital weight-based information as ITS and components offer ever-greater capabilities

Words | Jon Arnold, Intercomp, USA

Intelligent transportation systems (ITS) have experienced rapid advances in the technology, capabilities and deployments of expanding numbers of applications over the past decade. By understanding and improving congestion, conducting vehicle transactions such as electronic toll collection (ETC) and improving traffic safety through commercial vehicle screening, ITS systems provide operators with a wealth of information and tools. This enables roadways and system administrators to be more efficient while maximizing safety for the vehicle operators in a variety of ways.

With improvements in electronic technology in hardware such as cameras, and in software capabilities and communications, it can be easy to forget the advances being made to provide vital axle and gross vehicle weight (GVW) data from sensors embedded in the roadway.

Intercomp sensors use strain gauge technology, which has been recognized for its accuracy and temperature stability for measurement systems, and integrate it into a sensor that is embedded in channels cut into the roadway surface. Used for weigh-in-motion (WIM) applications at both low and high speeds, incorporating strain gauge sensor technology into ITS systems provides operators with accurate measurement of wheel, axle and GVW at speeds up to and beyond 80mph (129km/h).

With a nominal sensor size of 2.8in (70mm) wide, 3in (75mm) high, and ranging from 39-79in (1.0-2.0m) long, Intercomp strain gauge strip sensors require minimal invasive installations in pavements. The smaller sensor depth and dimensions enable rapid installations in a vehicle lane in a single day, without the drains or extensive civil works necessary with some WIM scales.

Tolling (ETC) and industrial axle and GVW check weighing are just a few low-speed WIM (LSWIM) applications that call for axle configuration and weight-based data with excellent accuracy. Coupled with

OCR cameras, RFID readers and other electronics and software, the WIM sensors provide the weight and axle data that form the foundation of the vehicle measuring event. The electronics then help link that data back to the proper vehicle and help to conduct the transaction.

Intercomp’s WIM strip sensors have the ability to operate within a wide speed range. Operators can use the sensors for low-speed applications down to 3-5mph (5-8km/h), or up to 80mph (129km/h) in mainline applications. Having a single WIM sensor for a variety of speeds simplifies operators’ choices and the work required to integrate components into an ITS system.

High-speed WIM (HSWIM) data collection and screening for enforcement are widely used throughout the world, and are the most common commercial vehicle applications. Acquiring axle weight and GVW is the primary purpose of these systems, and coupling the WIM sensors with electronics and communicating the data to officials downstream of the WIM site facilitates weight enforcement actions. Further, with advances in the performance of these systems, regulations are now being developed in some countries to allow direct weight-based enforcement based on WIM data.

When incorporated into sites with existing electronics, or operated as a standalone system with a variety of peripheral equipment such as cameras and gates, Intercomp strip sensors provide weight data that remains vital to conducting vehicle transactions, and protecting roadway surfaces and the people that use them. n

Opposite: WIM sensors in