Over 1,100 tonnes of salt was saved by Lancashire County Council last winter after it reduced the minimum temperature which had to be forecast before deploying its gritting lorries.
Previously, highways staff had turned out to treat the roads if the surface temperature was expected to dip below one degree Celsius. But during 2018/19, that threshold was cut to 0.5 degrees.
The change of policy meant that 312 fewer individual treatments were carried out than would have been the case if the previous intervention level had been maintained – saving around £82,000.
A meeting of the authority’s internal scrutiny committee heard that there was no difference compared to previous winters in the proportion of inaccurate forecasts with the potential to incorrectly influence decisions about whether or not to send out the gritters.
Forecasts for the county remained more likely to be “pessimistic” in their predictions about temperature – 4.5 percent of weather updates suggested the temperature would fall below freezing when it did not, while three percent indicated temperatures would remain above zero when they actually fell into negative figures.
Members were told that the 0.5 degree threshold provided a further buffer to offset the risk of an inaccurate forecast.
Phil Durnell, the county council’s director of highways, said the mild weather last winter had led to a more “marginal” forecasts about whether temperatures would stay above freezing, putting the new policy to the test.
County Cllr David Whipp said he was pleased that the committee’s previous concerns about the possible effects of the change had not come to pass – but wanted to know if more isolated areas had felt the benefit of the new way of working.
“There were requests made [last year]…for some of the savings to be transferred to permit [more] secondary routes to be treated – did that take place?” he asked.
The committee was told that the mild temperatures last winter meant that there had been little need to treat more minor routes – which are usually visited only if there is spare capacity after priority roads have been gritted.
The intention is for the new threshold temperature for treatment to be maintained, but with staff kept on standby throughout the winter season “to ensure they can respond in short timescales to any foreseen or unforeseen weather situations”.