intelligent sensors for Advanced Road Weather Information systems (rwis)

High performance road surface temperature & present weather sensors to update your existing road weather information systems or rail ice warning systems or new RWIS installations, Lufft's UMB (Universal Measurement Bus) technology with open protocol, offers a lean modular strategy that will communicate with any 3rd party hardware such as Variable Message Signs (VMS), Traffic Control Centres and OEM system integrators.

For an independent overview on the Lufft IRS road sensor performance the AURORA report is available here 5.3MB (opens in a new window)

A quick summary of each sensor is given below, but if you need the full story, please request a copy of the product data sheet, either by phone (01767 692692), email or use the Contact us link, filling in the details as required. Thank you.

Road Temperature sensor FAQ's

Download Lufft RWIS 2009 brochure:

Road & Runway Surface Temperature & Present Weather Sensors for Advanced Road Weather Information Systems (RWIS)
Lufft IRS21 Passive Intelligent Road Surface Condition Sensor The IRS21 passive road sensors are designed for transmitting road surface conditions to traffic management & Ice Warning Out Stations. The two part design enables the combined sensor/electronics to be exchanged for maintenance or calibration in a matter of minutes. The following key parameters are measured: Road Surface Temperature Water Film Height up to 4mm Freezing temperature calculation for NACL Road surface condition (dry/damp/wet/ice or snow/residual salt/freezing) The sensors can be addressed and therefore networked. Optional 2 deep sensor versions available. Now with Lufft's UMB technology, the IRS21CON UMB module converts the sensor output  to UMB protocol & also software updates/configuration is simplified using the UMB RS232 port.   Lufft IRS31-UMB Passive Intelligent Road/Runway Surface Condition Sensor. The IRS31-UMB passive road sensor is built into the road, flush with the surface. The two-part housing design enables the combined sensor/electronics unit to be exchanged for maintenance or calibration purposes in a matter of minutes. The following measurements are taken: - Road surface temperature - Water film height up to 4 mm - Freezing temperature curves for up to 10 types of de-icing materials - Road condition (dry/damp/wet/ice or snow/residual salt/freezing point) Optional 1 or 2 deep temperature sensor versions (5 & 30 cm depth). The IRS31 offers UMB (Universal Measurement Bus)connectivity to UMB modules, this offers open protocol communication directly to any manufacturers hardware. Key Benefits : Replaceable in situ sensor/electronics (each replacement module supplied with calibration certificate). Request over UMB protocol Radar technology to determine road surface water depth Supports up to 10 ice melting materials   Lufft ARS31-UMB Intelligent active road/runway sensor: The active ARS31 sensor is installed flush with the road/runway surface & calculates the freezing temperature by means of active cooling and heating of the sensor surface. The freezing temperature measurement is independent of de icing mixture. The two-section housing design allows the combined sensor/electronics unit to be removed for maintenance purposes at any time, in just a few minutes. In conjunction with interface converter 8160.UISO, the sensor can be built into new & existing UMB networks. Passive sensor IRS31 & active sensor ARS31 can be combined without difficulty, in fact this is recommended. The sensors are addressable and hence can be networked.   RWIS Software
Lufft R2S-UMB Radar Precipitation Sensor (Present Weather) for road, rail & drainage applications The speed rate of drops is registered with a 24 GHz doppler radar system. By comparison between the speed rate & the size of drops, the quantity of rain or its intensity will be registered. The precipitation type (rain/snow/snow-covered rain/freezing rain/hail) is determined thanks to the speed rate of the rain. Resolution up to 0.01mm, without maintenance. The principle is that of an electronic tipping bucket. Now includes SDI-12 output.   Read what one comany says about Lufft's R2S:
Lufft Visibility/Fog Detection sensor VS20-UMB Easy installation and maintenance Forward Scatter measurement process The visibility sensor measures visibility up to 2000M. For applications in the traffic engineering, a measuring range up to 1000M is sufficient. Two interface options:4-20 mA analogue interface & an RS485 digital interface to connect to UMB modules. A calibration device with a defined visibility is available as an option.
Lufft Snow Height Sensor. Robust measurement head with long-term stability Integrated temperature compensation High-energy ultrasound pulses
Lufft UMB Technology-Universal Measurement Bus. ISOCON/ANACON The UMB interface system is new technology for recording environmental data. Regardless of whether in the form of a standard weather station or road ice warning equipment, the modular system excels due to easy commissioning, free firmware updates & data transfer over RS232, RS485 or GPRS modem. UMB offers flexibility, modularity, web-based visualization & polling software.     Link to Lufft UMB Sensor Technology micro-site
The LCOM (Lufft-Communicator) An industrial PC with the Windows-CE operating system. The following interfaces are available for communication purposes: - USB - CDMA modem (RS232) - Party line modem (RS232) - UMB bus (RS485) Conversion to the following standard protocols can be made in combination with the UMB technology: TLS NTCIP TLS over IP with GPRS (Asfinag) DGT XML (Asfinag) Synop (in planning)
Road Weather Camera "Virtual eye on site" in conjunction with measurement data: - Creates trust & visually illustrates measurement data - Recommended combination especially in conjunction with ice warning systems   to limit patrols to the greatest possible extent - Images of road condition day & night in real time with infrared spotlight (option)   & GPRS transmission Dual lens outdoor, weatherproof (IP65), –30 … +60 ° C Lenses Wide Angle (43 mm, F 2.0 Resolution VGA (640 x 480 pixels each), color + B/W Sensitivity Color 1 lux (t=1/60s) 0.05 lux (t=1/1s) Interfaces Ethernet 10/100 Mbps, RS232 Power Supply PoE or MX30V Accessories Infrared spotlight LED Surge protection
Infrared Spotlight For use in combination with the Road Cameras above to give 24 hour scene vision in real time.
SOFTWARE Collector/SmartView3 Functions: Web based visualisation & data collection software for Lufft data loggers/transmitters Storage of data in database. Flexible export / import functions for integration of external/third party software / data (CSV & XML). Simultaneous data collection via unlimited communication modules (e.g. modems). Integration of web cam pictures (via TCP / IP-FTP). Basis version Collector (Collector for up to 5 stations) Order-no: 8160.COLLECT05 Unlimited version Collector (unlimited quantity of stations) Order-no: 8160.COLLECT SmartView3 incl. Collector up to 5 stations Order-no: 8040.SV05 SmartView3 incl. Collector unlimited (Web visualisation) Order-no: 8040.SV300 New functions: - extremely flexible alarming (SMS, email, voicemail) - 6 hour forecast module

                Please contact us if you require any further details or to request a brochure.                                                        

A range of meteorological sensors for road weather information systems (RWIS) & other weather station applications requiring high performance modern sensor technology with open protocol for measurement of road surface conditions, precipitation type(rain/snow/hail) & amount, visibility & snow depth.

Road Weather Information Systems (RWIS) consists of specialized weather stations that provide information on surface conditions on the pavement (road) surface in addition to standard weather information such as air temperature, dew point, wind speed, etc. The road surface data, such as temperature, presence of moisture & salt concentration & the freezing point of liquid on the roads are what differentiates Lufft's intelligent road sensors from its competitors, & provides enhanced valuable information to winter maintenance managers responsible for the decision of sending out salt/gritting trucks.

This surface data is typically used to forecast road surface conditions & initiate anti-icing procedures. Anti-icing consists of spreading salt on roads just before freezing pavement temperatures reached. However, in order to ensure rapid and targeted interventions, the actual information on the present weather situation and the road surface conditions are indispensable. Since ice formation occurs at certain critical points, such as bridges, an installation of an RWIS outstation at any of those critical points would be necessary in order to correctly determine the road conditions & to react correctly.

Road surface temperature: The sensor measures the "sun temperature" 2 mm below the surface. The most important temperature measurement for ice warning systems.

Road depth temperature - Depth 1: The sensor measures at a depth of, for example, 5 cm below the road surface. Typically the road surface temperature graph follows a similar path with a time delay. Road depth temperature - Depth 2: The sensor measures at a depth of, for example, 30 cm below the road surface. Compared to the road surface temperature the measurement only changes very slowly. After a long cold phase the measurement is often below 0°C, so that critical road conditions can arise even when the weather changes from"dry/cold" to "warmer/humid" and the air temperature is above zero.

Freezing temperature: The sensor measures the proportion of salt in the water and calculates the freezing temperature from this. This is the value at which the soluble liquid on the surface freezes (icing).

Water film: The sensor measures the water film height in micrometers. Aquaplaning usually occurs between measurements from 0.7 mm to (700
micrometers). The higher the water film, the higher the concentration of the deicer must be in order to prevent freezing. The freezing point is dependent on the concentration of the deicer and the actual water film height.

Salt concentration: The sensor measures the proportion of salt in the water and calculates the freezing temperature from this.

Road condition: The sensor measures whether the road surface is dry, damp or wet. Dryness, dampness or wetness is determined in accordance with the measured water film height (see above). The sensor also determines critical road conditions (slippery).

Precipitation quantity: The sensor measures and recalculates the precipitation quantity every minute. Typically this is output as "intensity per hour", e.g. 6.8 mm/h = 6.8 [l/m]/h. hour and the sensor has a very fast response time, the intensity is generally recalculated every 10
minutes.

Precipitation type: The sensor differentiates between the following typical types of precipitation (also described as "present weather"):

- Rain
- Snow
- Soft hail
- Hail
- Drizzle
- Sleet

Air temperature: The sensor generally measures the air temperature in an air permeable housing, which protects the sensor against direct radiation
& humidity, at a height of 4 M above the road (on the mast). In the event of solar irradiation, the air temperature measurement varies considerably from the road surface temperature.

Dew point: Dew point is the calculated temperature at which the ambient air is unable to absorb any further moisture, i.e. the air drops out water in
liquid form (mist formation). A road surface temperature below the dew point leads to the formation of frost (at road surface temperature < 0°C).

Relative humidity: The sensor generally measures the humidity in the radiation-protected housing at a height of 4M above the road (on the mast). The dew point is calculated on the basis of the relative humidity & air temperature.

The UMB (Universal Measurement Bus) system is improved technology for recording environmental data. Regardless of whether in the form of a standard weather station or road ice warning equipment, the modular system excels due to easy commissioning, free firmware updates & data transfer over RS232, RS485 or GPRS modem.

UMB offers flexibility, modularity & web-based visualization & polling software.

The UMB sensor library provides a comprehensive range of environmental sensors for recording temperature, relative humidity, precipitation, visibility & road conditions. The new WS series compact weather stations, in particular, are outstanding due to their unrivaled price-performance ratio. The top-of-the range model, WS600-UMB, incorporates sensors for temperature, relative humidity, precipitation, air pressure, wind direction
& wind speed.

The electrical connection for all UMB sensors is made via a standard plug connector system. This keeps installation & servicing costs to a minimum.

Third party sensors & existing analogue sensors can be integrated into the UMB system using the ANACON-UMB module.

All UMB sensors can be polled by means of a standard protocol. Once data polling has been incorporated for one sensor, additional sensors can be added by easy parameterization of the data polling system.

Channel-oriented sensor data polling delivers a large number of computed variables in metric and US format. Thus there is no need for conversion by the user. Sensors can be configured, equipment tested & firmware updated with the free configuration software (UMBConfig- Tool).

In addition Lufft offers a variety of software packages from data retrieval from weather stations (COLLECTOR) to web visualization (SmartView3) including a 6 hour forecast.