Drivers are being urged to watch out for icy conditions on the roads amid forecasts the bitterly cold weather could last over a week.
The Met Office has issued nine severe weather alerts in England which will remain in place until Friday.
Road conditions in north Yorkshire have been described as "extremely treacherous and dangerous" by the fire service.
Police said there had been 160 crashes in the county since heavy snowfalls at the weekend.
One involved a lorry that jacknifed on the A1 near York causing lengthy tailbacks in both directions. Luckily, no-one was hurt.
The southbound carriageway has since re-opened.
A Highways Agency spokesman said: "What we have had is a situation of localised showers washing away salt but also freezing upon contact with sub-zero temperatures at the road surface.
"Drivers should be aware that local conditions can change - often suddenly in winter - and heed advice and drive to conditions exercising extra care and vigilance."
There were reports of a three-vehicle crash on the A12 near Martlesham in Suffolk involving a school coach. A car driver was apparently injured.
Meanwhile, police have appealed for witnesses to a crash in Bishop Auckland in County Durham on Saturday in which three teenagers were badly injured.
A Durham police spokesman said: "Due to the icy conditions the driver of the Fiesta, a 34-year-old local woman, was unable to slow down sufficiently to avoid colliding with three teenagers who were walking on the nearside footpath.
"The three were then either carried on the bonnet of the car or dragged alongside it for around 40 metres before the car collided with a Vauxhall Insignia which was parked on the roadside."
Anyone witnesses are asked to contact the investigations team on 0191 375 2159.
The Met Office has downgraded an amber warning of icy conditions to a "less significant" yellow warning telling people to "be aware".
But much of England remains under a cold weather alert of Level 3, which warns of a "100% probability" of severe cold weather and icy conditions.
A Met Office spokesman said: "At this stage, the cold weather looks like it will last through to the end of the week with the temperature threshold expected to be exceeded across most parts of England."
Thick fog has caused some delays to flights at Manchester Airport, with fewer planes being allowed on the runway.
Travel disruption at Heathrow airport has eased following criticism operators axed around half of Sunday's 1,300 flights unnecessarily.
BAA , the company that runs the airport, has defended the move, insisting its "snow plan had worked far better than in previous years".
Flights were also disrupted at Luton, Stansted and Birmingham airports over the weekend and there were delays on some train services.
Many drivers were badly hit by the snow. Dozens of cars were abandoned on the M40 near High Wycombe and there were long hold-ups on other roads, with some drivers forced to spend the night in their vehicles.
Church Fenton in North Yorkshire saw the biggest snowfall over the weekend, recording 16cm (6in).
The recent icy spell has seen daytime temperatures plummet four or five degrees lower than average for February - traditionally the coldest month of the year.
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