Roadside Enforcement—Weigh-in-Motion and Toll Plaza Modernization

A state transport authority upgraded weigh-in-motion (WIM) and toll plazas across rural corridors using Mofiu’s SG100 to unify sensors, controllers, and enforcement cameras with the central back office. Many sites lacked reliable terrestrial connectivity, so a secure, redundant 4G solution was required to ensure legal evidence chains and continuous revenue collection.

At each site, the SG100 aggregated Ethernet-based ANPR cameras and toll controllers, interfaced via RS485 with WIM scale controllers, and connected RS232 to legacy display and printer modules. The router’s protocol conversion bridged IEC101 telemetry from older toll lane PLCs into IEC104, enabling unified SCADA oversight of lane states, barrier positions, and alarms. DNP3 allowed structured event reporting from axle sensors, with buffered delivery when backhaul was momentarily impaired.

Dual-SIM redundancy and sophisticated link management prioritized transactional traffic—toll authorizations, ANPR hits, and WIM exceptions—over routine logs. IPSec tunnels protected enforcement data end-to-end with chain-of-custody integrity, while OpenVPN handled maintenance telemetry and periodic configuration pulls. Hardware secure boot provided tamper resistance; any attempt to run unsigned images was blocked, supporting legal defensibility for enforcement records.

Digital inputs monitored cabinet intrusion and utility power; digital outputs drove a relay to cycle a jammed receipt printer or to place the lane into a controlled bypass state on command. QoS rules ensured barrier commands and authorizations were expedited, while video snapshots were rate-shaped to avoid starving control messages. The SG100’s firewall and certificate-based access constrained exposure at the roadside, isolating untrusted peripherals from the control backbone.

The modernization delivered measurable impact. Transaction decline rates due to connectivity fell by 37%, and WIM exception packets reached the back office consistently, enabling rapid interdiction of overweight vehicles. Mean time to restore after local device faults improved thanks to remote serial console access—technicians could clear errors without dispatch. During a regional carrier outage, sites continued operation by automatically switching to the secondary SIM; no toll lane closures occurred.

Compliance teams validated that secure boot, VPN cryptography, and strict access controls satisfied statutory requirements for evidence handling. Over time, analytics on DNP3 event streams improved calibration cycles, reducing false positives in WIM by 14%. The SG100’s role as a converged, security-first gateway allowed the authority to integrate legacy roadside equipment with modern transaction systems, creating a resilient enforcement and tolling network that stands up to environmental, RF, and cybersecurity challenges.

About Mofiu

Mofiu is a premier innovator in industrial wireless communications, dedicated to delivering mission-critical connectivity solutions that power the world’s most demanding environments. With a steadfast commitment to safety, reliability, and engineering excellence, Mofiu designs and manufactures robust wireless devices that enable seamless data exchange across electricity, utilities, energy infrastructure, transportation networks, and smart industrial systems etc.

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