May 02, 2017The Hampshire County Council (HCC), in southeast England, is evaluating the results of a "smart winter service" road-management system trial in which Internet of Things technology automatically recorded the road surface temperature conditions on a busy thoroughfare, to help validate de-icing treatments. The system, which uses ZigBee-based RFID technology, as well as ultrasonic sensors, was piloted throughout the 2016–2017 winter season to determine if road and ambient temperatures could be accurately captured in real time, as well as whether that data could be used to make roadwork decisions.
The system is provided by Mayflower Smart Control, with infrared-based road surface temperature sensors, as well as Libelium solar-powered Waspmote Plug & Sense! Platform ambient temperature sensors. The technology was installed at five locations along 40 kilometers (24.9 miles) of a high-priority gritting (salting) area in the Winchester section of Hampshire County.
The solution is not used during summer months, but remains installed on roadways as the Hampshire County Council determines its next plans. Throughout the pilot, however, HCC did not depend on the sensor data alone to make decisions regarding road treatments. Instead, it continued to employ a more traditional system from a third-party forecast provider
During the past winter, counties throughout England saw an uptick in requirements for salt to melt snow on ice and roads. Altogether, English councils ordered 1.3 million tons of salt for the winter season, which was about twice the amount used the previous year. As roads become busier, the need for optimum salting treatments increases, according to Libelium, the technology provider. De-icing salt has economic and environmental costs, and HCC wanted to ascertain if new, lower-cost technology would help automate the process of collecting data regarding road conditions, so that gritting could be provided as soon as it is needed, in appropriate amounts. Without such technology, county councils must check weather forecasts and conduct physical inspections to identify the need for road surface treatment.
HCC worked with Amey—its highways maintenance partner, which manages vital infrastructure and business services across the United Kingdom—to create a solution. Amey helped to identify a system from Mayflower Smart Control, which was already providing lighting control on the county streets.
The system consists of Mayflower Smart Control street-lighting controls connected to Libelium WaspMote Smart Agriculture PRO sensors, and Wintersense road surface temperature sensors, which together provide temperature readings on the road surface itself and in the air around the road. Mayflower installed the five Libelium WaspMote sensors in October 2016, says Muhammad Ali, Mayflower Smart Control's senior product-development engineer. While only a handful of sensors were installed this year, he says, a single Mayflower gateway unit can control up to 500 lighting-control ZigBee nodes, so the system can easily be expanded using the existing Mayflower gateways.
At regular intervals, the Waspmote sensors captured temperature data and forwarded that information, along with a unique identifier, to a Mayflower gateway, using the ZigBee protocol. The Mayflower gateway then forwarded the collected data via a cellular connection to the Sentilo open-source cloud-based platform. Amey next received that data, including the time and information about the road conditions that could be used to make gritting decisions.
"The aim is to improve our information to assist decision-making on when to undertake salt treatments," says Tim Lawton, HCC's head of highways, "particularly on those very marginal nights when there is lower confidence in the predicted road surface temperatures."
Because the county was already using Mayflower's street-lighting control and monitoring technology, Lawton explains, "It made economic sense to seek the opportunity to trial the Mayflower system to maximize its potential use in delivering operational services." The Winchester area location was selected for piloting "due to the route going through both rural and urban areas," says Gemma Prior, Mayflower Smart Control's marketing and bid associate.
The county used the data to analyze against events that had already occurred or that were happening during the winter, as well as against reports from office weather stations and other information. "If the results from new sensors prove to be valuable," Lawton states, "then next winter, the data from deployed sensors will be used to make go/no-go decisions for gritting."
The county indicates that it is too early to evaluate the technology's performance. However, Lawton says, the system seemed to provide information that could be used to help determine whether gritting was necessary on a particular day or evening. "Pre-salting activity has to be completed before ice forms on the road," he explains. "Hence, the more detailed information received of the predicted temperature forecast, the more accurate our decisions."
