Vaisala for winter roads: weather stations, MD30, forecasts

In winter maintenance, the equipment comes into play in three places: fixed road weather stations with sensors in and beside the road surface, the MD30 sensor that measures road conditions from the vehicle, and software that combines measurements and forecasts into proposed actions. According to Vaisala, MD30 can be connected to control systems for dynamic spreading, so that the amount spread follows the measured road conditions.

Weather stations and sensors in the road surface

RWS200 is Vaisala's road weather station. It can be used as a fully equipped system or to fill gaps in an existing station network. Sensors that measure the road surface itself can be connected to the station:

• DSC211 uses a laser to distinguish between water, ice, slush, snow and frost, and it determines the road grip.
• DST111 measures the road surface temperature non-intrusively, day and night, using infrared radiation.
• DRS511 is embedded in the road surface. It measures the amount and concentration of the chemical applied, as well as temperatures, to determine whether there is enough salt to stop the road surface icing over.

Trafikverket and Statens vegvesen

In Sweden, Vaisala entered into a five-year framework agreement in 2019 with Trafikverket (the Swedish Transport Administration) for at least 600 road weather stations, with deliveries planned for 2020–2024. Statens vegvesen (the Norwegian Public Roads Administration) writes that it assesses the need for salting on the basis of observations from weather stations, inspections and weather forecasts, together with local knowledge and previous experience, and that conditions can vary greatly along the same stretch of road. The sources do not say who supplied the weather stations along Norwegian roads.

MD30 measures road conditions from the vehicle

MD30 is mounted on the snowplough or another vehicle and sends data on road conditions, road grip, the thickness of water, ice and snow layers, and the road surface temperature along the route. It also gives relative humidity, dew point and air temperature. Vaisala says that MD30 fills the gaps between the fixed weather stations, so that you can see conditions across the entire road network. Among other things, the driver is told:

• whether there is black ice
• whether there is water or ice on the road, or whether the asphalt is just damp or darker in colour
• when the road surface temperature is falling and action is needed to prevent it becoming slippery
• whether more or less material should be applied, and what is left behind after the plough

Dynamic spreading: readings control the amount

Vaisala calls it dynamic spreading when sensors on the vehicle and a computer-controlled dosing system automatically adjust the amount to the road conditions there and then. The data from MD30 goes into the dosing system, and the material is applied at a rate set in advance according to road grip, or in some cases according to road surface temperature and layer thickness. Each organisation sets its own amounts, using an action matrix as a starting point. According to Vaisala, this means the driver does not have to adjust the amount on the move.

Vaisala developed the action matrix together with people from the road sector. It assumes pre-wetted salt and a two-hour cycle time. Vaisala gives suggested salt amounts by road grip and road surface temperature, but states that the figures are only suggestions, that Vaisala accepts no responsibility for them, and that each organisation should follow its own procedures and required standards. Pre-wetted salt is explained in Dry salt, pre-wetted salt or brine?.

Vaisala cites salt savings of 20 to 55 per cent in spreading projects with MD30. These are the supplier's own figures. In a pilot in northern Italy, MD30 recorded data every other second from a bus during the day and a patrol vehicle at night. The Bucher Assist solution calculated the amount for each location and sent the settings to the gritting truck every five minutes. According to Vaisala's account, salt consumption fell by an average of 53 per cent over the winter.

RoadAI: video and images from the road

In a press release from 2019, Vaisala described RoadAI as its platform for video and images from the road. In summer it detects cracks and potholes in the surface, and in winter MD30 can be connected to RoadAI, so that the images can be used in the office to check the road conditions the sensor has recorded. We have not been able to find out whether RoadAI is offered in the same form today.

In Norway, Statens vegvesen, Mesta and Klimator have carried out the pilot project “Ahead”, in which a laser, camera and sensors on the snowplough truck read the road conditions and adjust the amount of salt. See the guide on the Ahead camera.

Forecasts and decision support

Wx Horizon, which Vaisala launched in 2020, gathers real-time data from mobile sensors, IoT sensors and road weather stations, including those from other manufacturers, and uses mobile observations to improve forecasts along the routes. The service is intended to help the operations manager prioritise actions and use salt and brine more efficiently. Today, Vaisala offers Xweather Horizon, which is intended to give an overview of current and upcoming road weather across the entire road network. The forecast models use data from local sensors along the roads.

According to a customer story from 2021, Svevia chose Vaisala's MDSS decision support system for its entire organisation. The system is set up to suggest routes and actions.

Vaisala, BM and Falköping in a Swedish research project

In the Swedish research project “Prognosstyrd dynamisk vinterväghållning”, the decision support from Klimator (RSI) and Vaisala (MDSS/Horizon) was assessed, and mobile sensors such as MD30 and AHEAD were tested to see whether road condition data can be used as forecast data.

The final report from August 2023 states that Svevia had held an initial meeting with Vaisala, BM System and Friggeråkers Verkstäder (Falköping) about testing automatic salt spreaders in Enköping in the winter of 2023/24. One option considered was for Vaisala to send a forecast-based salt amount via BM, which would add the spreading width from previous runs, to the connected Falköping spreader. We have not been able to find out whether the test was carried out, or what it may have shown. There is more about BM in BM Smartbox and BM System, and about Klimator in the guide on Klimator and Saltera.

What this means for a Falköping spreader

Falköping states that forecast-controlled spreading has been developed exclusively for, and is available together with, its own control system and Panel PC. The Panel PC is prepared for data collection, GPS and GSM transmission, control by road surface temperature and external communication using the CEN/DAU protocol. If the spreader is to receive data from MD30 or from a forecasting service, you will need to check with the suppliers what is possible in your case.

Ask us about the control system and data collection for the Falköping spreaders, or read more in GPS-controlled gritting and forecast-controlled gritting. You can reach us via the contact page.