The Biral SWS visibility and present weather sensors are used for single installations or multiple sensor networks . . .

. . . where visibility and present weather information is needed to improve road safety.


To download the text and diagrams on this page please click on
SWS Roadside Weather Sensors brochure (pdf 1.38 Mb)

Application examples:

Network of sensors in Dubai for improved road safety
Microstep road sensor references (pdf 1.18 Mb)

Video clip
SWS-100 road video clip

(links open in a new window)

Roadside weather can be dangerous and costly

Dangerous Driving Conditions

If you are responsible for road safety you know the weather conditions which cause the greatest problems.

Fog can occur in patches at blind spots, such as dips in the road, near a river or around a corner without any previous warning causing an unexpected hazard.

Falling precipitation such as heavy rain or snow lowers the visibility of the road ahead and affects drivers’ vision through the windscreen as the precipitation lands on the glass.

Spray from vehicles passing over standing water (from precipitation that has fallen too heavily or quickly to drain away) reduces a driver’s visibility especially at higher speeds.

When road surfaces are icy or snow has settled, roads need to be treated quickly so drivers have traction in these dangerous conditions.

Sand or dust storms can blow across large stretches of the road at astonishing speed and very suddenly cause a dangerous driving situation in near zero visibility.

Road Management Costs

Road maintenance, especially in winter, is costly in terms of time, people, machines and materials. Even more so if the weather information on which your action is based does not reflect the local conditions or is badly timed.

Road users rely on very high levels of accuracy from roadside warnings and expect timely gritting of roads so it is important to get it right first time.

Additionally, the economic effects of traffic congestion caused by bad weather can only be minimised by effective action from the agencies responsible.

So how can you make sure you respond quickly and effectively to these requirements?

The Biral SWS present weather sensors are all you need to save valuable time and money when it counts most and satisfy the demands of road users.

Use Biral SWS visibility sensors to improve safety

Biral SWS present weather sensors are typically installed within 3 m of the roadside and measure the local weather conditions (fog, snow, rain, spray, sand and related parameters).

The information provided by the sensors is easy to understand and integrates into any control system. The sensor switches a warning sign locally via relay and / or transmits the data via a second data output to a an ITS control centre.

The Biral SWS sensors provide reliable, consistently accurate weather information day and night. This allows you to make timely decisions about spraying or gritting road surfaces and switching road warning signs, therefore, achieving the best results from limited and valuable resources. Road users will be less stressed, safer and happier with their journeys and tax payers’ money will have been used
The Biral SWS sensors come with a 24 month warranty and require very little maintenance. There are no consumables so running costs are a thing of the past. The only maintenance required is to clean the optical windows once every 3-6 months using a normal clean cloth and some water. The sensors even provide information on how dirty the windows are so that you can prepare for the maintenance and only clean the unit when it is absolutely necessary, thereby eliminating any expensive fixed or regular scheduled maintenance.

Features of the SWS road weather sensors safety

SWS-100 SWS-200
Specific range for tunnels / fire / fog prone areas Yes No
Provides quick response to changes in weather (10 seconds) Yes Yes
Reports when snow, rain, fog or sand are measured Yes Yes
Reports precipitation details such as accumulation amount and intensity No Yes
Automated reports output every minute Yes Yes
User adjustable reporting period (10 seconds to 5 minutes averaging time) Yes Yes
Fog or heavy precipitation reported in 10 m ranges for accurate reporting
to gain road users trust (range 0-2000 m)
Yes Yes
Measures dust, smoke or sand restrictions to visibility Yes Yes
Measures restrictions to visibility that road users will see from spray (from
standing water, even when no precipitation is occurring)
Yes Yes
Indicates when maintenance is required (maintenance takes 10 minutes) Yes Yes
Remains functional and accurate when maintenance is indicated Yes Yes
Trusted history and proven reliability Yes Yes
Does not require any spare parts or consummables Yes Yes
Switches road warning signs directly when hazard occurs Yes Yes
One network connection and an extra connection for easy local maintenance
(no need to disconnect the sensor from the network during maintenance)
Yes Yes
Sensor can be calibrated by the user when needed Yes Yes
Annual calibration optional Yes Yes
Not affected by healights or other nearby light sources Yes Yes
Operating status monitored and reported for quality control Yes Yes
Approved and used on road weather systems internationally Yes Yes


The Biral SWS delivers reliable and consistent results

Biral visibility and present weather sensors have been used in all weather conditions and locations around the world.

The Biral SWS sensors are based on the legendary Biral VPF sensors which have been used on airports and in extreme weather environments for decades and trusted by professionals and scientists.

Due to the advanced concepts of the Biral SWS sensors they are superior to competitors’ sensors for accuracy of measurements, and correct identification of conditions and:

are robust enough to withstand the aggressive roadside environment for many years without spare parts or consumables

have a measurement concept that is valid in both rain and snow l avoid false readings from external sources or from vibrations of the sensor itself

are not affected by reflections from the road surface in rain or snow or from approaching car headlights


SWS-100 road weather sensor


SWS-100 VISIBILITY SENSOR   Visibility and present weather sensors

SWS-200 – similar to the SWS-100 but with extended precipitation capability



SWS-200 VISIBILITY SENSOR   Visibility and present weather<br /><br /><br /><br /><br /><br />