If you can't avoid the fog entirely, the first thing you should do is increase the space between your vehicle and the vehicle in front of you, which can become quite a challenge because fog can reduce your visibility to nearly nothing. SERNIS Smart Detector Beacons System is activated in foggy situations and uses LEDs to guide and warn the drivers of the presence of another vehicle in front.
Chain collision accident due to dense fog
The adverse weather conditions of dense fog in Autovía del Cantábrico, A-8 in Spain were causing dangerous driving conditions. The last section put into service - Mondoñedo- Vilalba - is located in Alto de O Fiouco, 698 meters above sea level. Currents or air masses from the Cantabrian Sea stationed in this area are continually creating fogs by orographic elevation.
Cameras and weather stations with visibilimeters that send information to the Northwest CGT every minute were installed on the highway. Since visibility conditions change very quickly, it generated a low efficiency in the use of the road and Dirección General de Tráfico (DGT) began to think about how to reduce the time lost in both situations, in the closure and in the opening of the highway.
Smart Detector Beacon System
In order to improve Road Safety in the dangerous highway section, the DGT launched an open tender to develop a smart system that could alert drivers immediately. It resulted in the development by SERNIS of the Project BICA (Balizas Inteligentes Climatologia Adversa, in spanish), a Smart Detector Beacon System for Adverse Weather, focused particularly on fog situations, now called SR-SDSFOG.
Each Smart Detector Beacon has two powerful LED beacon windows, amber and red, with brightness control, for guidance, as well a set of a dedicated sensors (like radar sensors) and local processing units to detect the vehicles and alert in real time the car drivers if they have the possibility to have some traffic in front of them, even with very limited visibility conditions. All the 382 units that covers a range of around 4Km of road are connected in a network by RS485 communication protocol, where it is possible to communicate individually with each set of the Smart Detector Beacons to monitor and control several internal parameters.
For scenarios of reduced visibility or environments in which the meteorological elements prevent a correct visibility, the smart system provides a luminous element of guidance and lane limitation in amber color and a warning and vehicle detection element in red color.
The system works according to 3 different scenarios:
- Under normal conditions, all lighting devices remain off.
- In low light conditions, either on a cloudy day or at night, the amber LEDs turn on to act as a guidance signaling device.
- In foggy conditions the vehicle detection and guidance lights are activated simultaneously. When the smart detector beacon system detects the passage of a vehicle, it activates the red LEDs in the device for a predefined time to warn the following vehicle of the presence of another vehicle in front of it. The guidance lights (amber LEDs) remain active as guidance signaling.
In addition to the main functionality, which is the detection and alert of vehicles, the smart detector beacon also monitors the traffic flow between every set of two consecutive systems, so that the software can make a continuous check of vehicle correlation between smart detector beacons and alerting for possible accidents.
The 382 units of smart detector beacons are installed at approximately every 48 meters, on a post of free height between foundation and box of 135 cm minimum height, on each side of the road, making at each point a detection “barrier” with doppler radar sensors.
The management software was developed according to all DGT requirements, including implementation and integration in the existing road equipment management application in the Noroeste Traffic Management Center.
After several tests that validated the results in the research, the system was finished being installed at the end of November 2021, making it safer for drivers who had to drive through the A8.
