Pavement Temperatures and Effects: How to get Pavement Temperatures
There are many methods available to determine pavement temperatures. A truck-mounted or handheld sensor provides a more accurate reading, while the weather forecast, local transportation department activities, and your state's road and weather information system also provide valuable data.
Using at least a handheld temperature sensor is highly recommended to ensure the maintenance response is most appropriate to the conditions and salt efficient.
Other methods for determining pavement temperatures:
Pavement temperature sensors
A digital handheld infrared temperature sensor can be used to measure pavement temperature more accurately. The sensors can be purchased for about $50 or less at auto parts stores, hardware stores, or big box stores. Be sure to select a sensor that can read temperatures below 15°F. If the temperature reading keeps changing, the device is not acclimated to the cold yet. Give it enough time for the temperature reading to stabilize. Point the sensor at the pavement to get a pavement temperature reading.
Truck-mounted Sensor
Larger campuses or contractors may have vehicles equipped with truck-mounted temperature sensors. These are more accurate than handheld devices. They have an in-cab readout that provides air and pavement temperatures. The sensors can be mounted on pickup trucks or larger trucks.
Mini Weather Stations
Temperature sensors and cameras can be mounted on poles on a property within or on the edge of the parking lot. Since they can be accessed remotely, these sensors provide specific onsite information to help determine when to deploy workers and equipment to plow and treat if needed. Cameras can show current conditions and can also provide before and after photos of site conditions. The remote service may include weather forecasting. Warnings can be added so property managers or maintenance supervisors know when an event is coming so they are prepared to deploy to the site at the appropriate time. Weather stations can provide cost savings if deployment can be delayed based on more accurate and site-specific information.
Watch how local transportation departments respond
You can learn a lot about an approaching storm by paying attention to what local transportation departments are doing. If you see lines on the pavement, it usually means a storm is forecast and roads are being anti-iced to prevent bonding of snow to pavement.
You can also look at the color of the deicer being used. White material is typically regular road salt (sodium chloride), while green or other colored products are often a treated salt designed to work better in colder temperatures. Sand use, if deicers are usually used, may indicate cold or very cold pavement temperatures.
Pavement temperature trend
In addition to pavement temperature, it is important to consider the temperature trend. Check the weather forecast to see the predicted weather conditions and temperature. If it is sunny or the sun will be coming out, the pavement will warm up. If air temperatures are rising, the pavement temperature will likely rise slowly too. The trend can help determine if a deicer is needed or melting will occur on its own or if rain or meltwater will freeze on the pavement as temperatures drop. If it is forecasted to warm above freezing, you may not need to use salt. After a snowstorm, temperatures often drop quickly. Be prepared for colder pavement and try to remove snow as soon as possible before it gets too cold for deicers to work well.
State RWIS system
Most state departments of transportation manage Road and Weather Information Systems (RWIS) throughout the state. The stations are located next to highways and have sensors embedded in the pavement to collect surface and subsurface information. Above ground instruments monitor air temperature, wind, and other parameters. Many states allow access to some of the information. For example, Minnesota has a 511MN website that has camera views and weather and pavement condition information from RWIS stations. Air and surface temperature (aka pavement temperature) in addition to humidity, road conditions, precipitation and much more information can be viewed.
The 511MN information is also available as a mobile app. Check your state transportation department’s website to see if they offer pavement temperatures and other winter condition information. These sites won’t provide the pavement temperature where you are, but can help you decide if the pavement temperature is likely to be lower or higher than air temperature.
