ILS-04 Laser-Based Free-Flow Vehicle Length, Width, and Height Detection System
ILS-04-103
Four-lane, single-post, cross-lane compatible, 9 LiDARs, 2 wide-height F13 sensors + 7 long-height F13 sensors.
The single-line free-flow system is a vehicle outline detection system specifically designed for multi-lane free-flow road sections. It adopts a mature “gantry-mounted + side-mounted” layout and consists of multiple high-frequency single-line LiDAR sensors arranged in an orthogonal scanning matrix. As vehicles pass through the gantry at speeds ranging from 0 to 120 km/h, the system can simultaneously acquire high-density cross-sectional data from both the top and sides, enabling it to reconstruct the vehicle’s three-dimensional model in real time.
This system completely resolves the occlusion issues that may arise when multiple vehicles are operating in parallel under a side-mount configuration, achieving precise coverage across all road surfaces with no blind spots. It supports flexible configurations for 1 to 4 lanes, perfectly meeting the demands of highway mainline weight enforcement, non-site law enforcement, and digital management of intelligent highway vehicles. It is currently recognized as the highest-precision free-flow detection technology available.
Keywords:
Category:
Free-flow system
Overview
Gantry orthogonal scanning, rejecting line-of-sight obstruction.
In multi-lane concurrent free-flow scenarios, side-mounted devices are easily obscured by larger vehicles on the outer lanes, making it difficult to detect smaller vehicles on the inner lanes. This system employs... Top-mounted gantry (width/height measurement) + Side-mounted (length measurement) The combination method, like a "heavenly net and earthly trap," covers all lanes, accurately capturing vehicles no matter how they are traveling side by side or weaving in and out, thus achieving true blind-spot-free detection.
120 km/h free-flow traffic, with zero interference.
Specifically designed for high-speed mainlines. Powered by F13 radar up to 100Hz Thanks to its ultra-high scanning frequency, the system can perform dense slice scans on vehicles traveling at speeds of up to 120 kilometers per hour. The vehicles don’t need to slow down or stop—instead, they undergo a precise “health check” of their exterior dimensions in just milliseconds.
Modular expansion—freely configure from 1 to N lanes.
The system adopts a distributed architecture. The number and placement of LiDAR sensors can be flexibly adjusted according to the actual number of lanes (1, 2, 3, or 4 lanes, plus the emergency lane). Whether it’s a two-lane one-way road or an eight-lane two-way road, a single control cabinet can easily manage the system, offering exceptional scalability.
Core features
- Core sensor: ILS-F13 Measurement LiDAR
- Applicable scenarios: Highway mainline, off-site enforcement points
- Speed range: 0 ~ 120 km/h
- Lane coverage: 1–4 lanes (more can be customized)
- Measurement accuracy: Length ±50 cm / Width ±10 cm / Height ±5 cm
- Scan frequency: 100 Hz (ensures high-speed detection density)
- Capture rate: ≥99%
- Environmental adaptation: Anti-glare and rain/snow filtering algorithm
The “Invisible Law Enforcer” of the Highway Mainline

Under the premise of not disrupting normal traffic flow, a single-lane free-flow system can conduct 24-hour uninterrupted “health checks” on all passing vehicles. It is typically used in conjunction with high-speed pre-inspection weighing systems (WIM) to precisely identify vehicles that exceed length, width, or height limits. Combined with license plate recognition data, this system forms a comprehensive off-site enforcement evidence chain, serving as the cornerstone for building a smart highway inspection and monitoring system.
Data is king; precision is paramount.

Multi-machine collaboration, data fusion
This isn’t merely a simple superposition of several radars—it’s a deep fusion of data. The horizontal radar at the top is responsible for outlining the vehicle’s width and height, while the vertical radar in the middle is tasked with measuring the vehicle’s length and detecting gaps.
The data from multiple radars are uniformly calibrated and stitched together in the controller’s spatial coordinate system. Even when a large truck is parked right next to a compact car, or when vehicles cross lane boundaries, the system can perfectly “separate” them and independently model each one, thanks to its multi-view point cloud data.

Millisecond-level response—no vehicle can hide from you.
The biggest challenge of free-flow systems lies in the inconsistent spacing between vehicles. The single-lane free-flow system is equipped with a vehicle separation algorithm specifically optimized for high-speed scenarios.
Combined with a high sampling rate of 100 Hz, the system can sensitively detect even the tiniest gaps between the vehicle ahead and the one behind, or the distinctive features at the connection point between the tractor and the trailer. Whether driving closely behind another vehicle or navigating complex semi-trailer combinations, the system can accurately determine whether “it’s one vehicle or two,” thereby eliminating potential enforcement disputes.

As steady as Mount Tai, unafraid of even the slightest tremor from the gantry.
Highway gantry structures may experience slight vibrations when heavy vehicles pass by or during windy conditions, which typically affects measurement accuracy.
The single-lane free-flow system is equipped with a vibration compensation algorithm and paired with a dedicated shock-absorbing mounting bracket, effectively eliminating data deviations caused by gantry sway. The core sensor F13 has undergone rigorous mechanical shock testing to ensure that its optical axis remains stable even in environments subjected to prolonged, continuous vibrations, eliminating the need for frequent calibration.

The worse the weather, the more evident true skill becomes.
Over-limit transportation often occurs at night or in bad weather, in an attempt to evade supervision.
The single-lane free-flow system employs active laser detection, which is completely unaffected by ambient lighting conditions. Its detection performance at night is just as reliable as during the day. Thanks to its unique rain and snow filtering algorithm, the system can penetrate moderate rain and dense fog, ensuring that the enforcement system remains online 24 hours a day, 7 days a week. This is an absolute advantage that visual solutions simply cannot match.
YINTAILI All-round Services
Gantry Layout Plan
Based on the road width and gantry height, we provide a precise radar deployment map to ensure 100% coverage.
Superiority Control Platform Integration
Provides standard API interfaces to facilitate data integration and upload with provincial- and city-level non-on-site enforcement platforms.
Remote O&M support
The system supports remote self-health checks, and our technical team can remotely assist in troubleshooting, thereby reducing the risk of on-site maintenance.
Explore more potential applications
Pre-Interception of “Three Excesses” Vehicles at Highway Entrances
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