Motorists are being warned to take extra care overnight and on Thursday morning with dense fog and freezing temperatures bringing difficult icy driving conditions.
Visibility could be below 100 metres on some roads, according to weather forecasters.
It comes after a woman driver in her fifties died and more than a dozen other people were injured in a 20-car pile up in Oxfordshire.
The crash during foggy conditions on Wednesday morning stretched more than 1km along the A40 near Witney.
A witness to the pile-up said poor visibility meant it was difficult for cars to see each other before they were “on top of it”.
Paramedics said freezing temperatures, icy road conditions and poor visibility had hampered rescue efforts.
The fog warning issued by the Met Office covers large parts of east Wales, the Midlands and eastern England.
Travellers should expect difficult driving conditions, longer trips and possible delays to their flights on Thursday.
Dozens of flights were delayed or cancelled due to poor visibility at London City Airport on Wednesday morning, while a number of arrivals were diverted elsewhere.
A Met Office spokesman said: “Combined with temperatures below freezing, there is also the risk of ice forming on some untreated surfaces particularly later in the night and early on Thursday morning.
“The fog patches are expected to slowly thin during Thursday, although some patches may persist throughout the day – most likely in a zone from the West Country to eastern England.”