A road has been closed after 12 vehicles crashed in three miles.
The A24 in Horsham has been shut because of black ice.
On the A24 five vehicles crashed at 10.05am
At 10.05am on the A264 at Broadbridge Heath there was also a two-car shunt.
Sussex Police said: "Police have currently closed a three-mile stretch of the A24 southbound in the Horsham area due to treacherous black ice today.
"The conditions on the road going south from the Robin Hood roundabout just north of Broadbridge Heath to the Hop Oast roundabout north of Southwater, Horsham, have caused at least 12 vehicles to skid and crash since 9.45am. This area is now closed.
"No one has been seriously hurt. A few drivers have minor injuries and damage to their cars.
"The northbound lane of the A24 is open but traffic is heavy. Traffic trying to move southbound is being diverted through Horsham. The southbound lane is likely to be closed for another two hours."
PC Glen McArthur from the roads policing unit said: "Miraculously no one has been serious injured. The conditions on this stretch of road are pretty bad. We are advising people to either avoid the area or find another route. Drivers need to slow down. If there is frost on your windscreen then be prepared for frost and ice on the roads."
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