National Highways officially switches over to autumn and winter operations today (1 October) – a procedure it has conducted every year since the 1960s.

Based on current weather forecasts, you are unlikely to see gritters spreading salt on the network or snow ploughs on the open road this weekend – our roads are only salted when there is a risk of ice forming. This could be when the road surface temperatures are forecast to drop below +1°C or when moisture could be present that could form ice.

However, you can be certain our highways managers and staff – working with meteorological experts from the Met Office, Metdesk and DTN are closely monitoring weather forecasts and are prepared for whatever conditions the autumn and winter season may bring.

Various behind-the-scenes activities come into operation at National Highways on 1 October. These include:

• Monitoring of detailed road weather forecasts from DTN and Metdesk and updates at various stages throughout the day, plus a daily national Met Office weather forecast. These are all assessed – even if no further action is required for the first few weeks if the weather is mild
• Vehicles have been maintained and serviced during the summer and are in position at their depots ready to go - whenever the call comes
• Drivers have been retrained during the summer season and are on winter rosters together with our autumn and winter decision-makers
• A team of Met Office forecasters are embedded at our National Traffic Operations Centre (NTOC) in Birmingham, providing weather impact advice, daily national and regional advisories and severe weather alerts to help inform our National Network Managers
• Our 21 regional severe weather plans have been reviewed and become live
• Gritting routes have been reviewed and updated where needed.

Darren Clark, Severe Weather Resilience Manager at National Highways, said: "We spend five months during the warmer weather gearing up for seven months of operations covering the autumn and winter period, right up to 30 April.

"October is an important month and has been for many years, giving us the opportunity to test and refine our plans before severe weather conditions arrive later in the season.

"From 1 October, we receive forecasts and updates at various stages every day during the autumn and winter period. Our decision makers will meet and decide the course of action – even if it is to simply confirm 'no action' amid warmer conditions.

"This is because as an organisation, we need to be fully prepared and ready for when temperatures drop, so we operate a well-established daily routine.

"It may be during any warmer spells in October the public see our drivers doing 'dummy runs' where they take gritter vehicles out along their designated routes – without any salt on board – in order to re-familiarise themselves with their journeys and identify any problems on route.

"As part of our planning for severe weather events we undertake severe weather desk exercises – these are usually round-table discussions where we run through a range of scenarios and test our plans and the responses of our staff so our plans can constantly evolve wherever needed."

During some years of the last five-year period, although not a regular occurrence, National Highways has salted some of its A-roads and motorways during the month of October when needed – and 2019 was significant when a few thousand tonnes of salt was used.

Air temperatures do not determine when roads are salted. Our roads are only salted when there is a risk of ice forming. This could be when the road surface temperatures are forecast to drop below +1°C or when moisture could be present that could form ice.

Abigail Oakes, Senior Account Manager at the Met Office, said: "We are delighted to continue our close working relationship with National Highways as we head towards the winter period.

"Our staff, be that meteorologists embedded alongside the National Highways team in Birmingham during the autumn and winter, or Met Office staff working from Exeter to deliver and support throughout the year, are proud to continue this partnership, which allows for the best possible support for road users during periods of severe weather."

Precision road temperature forecasting

The road temperature and weather forecast contracts with independent meteorological experts DTN and Metdesk run from 1 October to 30 April and complement the national Met Office weather forecast, by providing a level of granularity and precision about changing road surface temperatures across our road network.

For example, for the South West area of England, National Highways receives route-by-route forecasts four times a day for each of its 40 salting routes to help the team decide whether any salt spreading is needed over the following 24-hour period.

One set of data may indicate 39 of the route forecasts recommend no action, but if one particular route forecast indicates the M5 in Avonmouth could see the road surface temperature fall to -2 degrees C, then salting is necessary.

Why 1 October?

Many local authorities switch over to autumn and winter operations in November, but National Highways has always switched over in October.

Some local authorities are based in largely urban areas where latent heat in the road surface can keep a road warmer than in a rural area – making those road temperatures up to two degrees warmer. This means some councils operating in a city or built-up area may not need to spread salt on roads as early in the season as National Highways which operates nationwide in rural areas as well.

Explore more online:

National Highways has lots of advice on its website around travelling in severe weather conditions, including high winds and gales, fog, rain and snow and ice. Visit our travelling in severe weather web page.

Weather forecasts and information can be found on the Met Office websitehere.

Travel information can be found by visiting National Highways' Travel updates page, and by following @highwaysnwest @highwaysneast @highwaysseast @highwaysswest @highwayseast @highwayswmids, @highwaysemids @highwaysyorks on Twitter or calling the National Highways Information Line on 0300 123 5000.