People are being warned to take extra care while driving as thick fog settles across the county.
The Met Office has issued a yellow weather warning as visibility drops down to just 50m in some places.
The fog is expected to cause major disruptions during rush hour, before dispersing on Thursday morning.
Police are telling drivers to take extra care on the roads, advising them to use dipped headlights and fog lights, reduce their speed and maintain a greater distance from the car in front.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here