Lancashire County Council’s gritting policy is currently based largely on temperature alone. However, it is now being brought in line with national guidelines, meaning that in some dry conditions, less salt will be spread on routes than has previously been the case at the corresponding temperature.
However, wetter weather will often see more grit used compared to the current standard.
A report to the authority’s cabinet states that the new process will ensure that “more accurate amounts” of salt are deposited depending on exactly how much is needed.
Members were also told that the revised winter service plan for the county’s roads will take into account more nuanced temperature variations when determining how much grit to use.
Currently, salting amounts are amended depending on whether the forecast road surface temperature is within one of three different ranges. From now on, the level of grit laid down will vary across eight temperature bands.
The volume of traffic on the road when the salt spreaders are in operation will also be factored in – with greater amounts of grit used during overnight periods when there are fewer other vehicles on the road to enhance its effectiveness by driving over it.
“We can now better monitor with computer systems the rate of grit that we put onto the roads [depending on whether they are] dry, wet, damp or have snow on,” cabinet member for highways Keith Iddon explained.
“At one point we were over-gritting which can be dangerous.”
County Cllr Iddon also revealed that 11 new gritters are being added to the Lancashire fleet this year.
The greatest difference in the amount of grit used under the new plan will come within the -2 to -4 degree Celsius temperature ranges in dry conditions – here, it will drop by between 40 and 47 percent from current levels.
However, in most wet conditions, levels will either stay the same or increase compared to the calculation made on the current temperature ranges alone.
In periods of light traffic, between 11pm and 4am, a greater amount of grit will be used at almost all temperatures compared to the corresponding rates for those conditions in the current scenario where traffic volume is not yet a consideration.
Significant increases in salt spreading will occur in wet conditions overnight – with between 40 and 73 percent more used than would currently be the case at temperatures of between -3 and -5 Celsius.
There are no changes to the process of gritting roads after ice has formed or snow has fallen.
The meeting heard that adopting the national guidance will enable County Hall to better defend itself against legal claims.
The county council’s current winter service plan notes that “whilst a highway authority is obliged to take preventative measures in anticipation of ice or snow, the duty to clear ice and snow from highways maintainable at the public expense is not absolute”.
It adds: “The authority will be under no liability unless a failure to maintain safe passage so far as is reasonably practicable is proven. In other words, so long as the decision as to whether or not to act has been taken on reasonable grounds, with due care and with regard to relevant considerations, the highway authority will not be liable.”
The full winter service plan for 2020/21 is expected to be published in the coming weeks.