Best to be on the safe side. I live on a main road & it's absolutely clear today, was barely less clear yesterday morning, was perfectly safe on Thursday night (when I arrived home in a recovery vehicle). Southampton, a mere 20 miles down the road, OTOH…western end of the A27 was impossible on a scoot Thursday night, and that's a trunk road that's supposed to get priority for gritting. I had to walk the bike out of the car park, took half an hour to travel less than a mile, dropped the bike once (minor dings only, thankfully) and nearly went down multiple times more. Didn't try to get over there yesterday for fear of getting stuck or worse, no way to know if it would be safe enough. Walked round to my local delivery office- no-one out on walks, managers & customer office staff only. And there were no trains (to or from work) either. It's melting fast round here now, but definitely still a time for caution!