The contractor in charge of the site should make sure mud cannot get into public areas; and should arrange for the road/s to be cleaned if it does.
If you think mud or debris from a construction site is making the road dangerous, and the contractor does not seem to be taking action, tell the police as they may need to close the road while it is cleaned. The local authority or county council Highways Department may also be able to assist if the problem occurs on a road that they are responsible for. Their website will have details of how to contact them, and their phone number will be in the phone book
HSE does not have responsibility for these issues, but will take details of your complaint as we may need to find out why the contractor allowed this to happen.