As well as warning motorists to take care, police officers have also warned farmers of their legal obligations to help keep roads safe.
It comes as officers warned of a seasonal increase in the number of accidents reported during the harvest.
Ch Insp Steve Owen, from Warwickshire and West Mercia Police's joint operations department, said legal action would be taken against anyone found to be breaking the rules.**
Every year we face problems with agricultural vehicles leaving large amounts of mud and debris on the roads during the harvest season.
While the majority of farmers take steps to ensure they keep the roads clear and safe, not all are as diligent.
We would like to remind farmers and contractors of their responsibilities under the Highways Act.
We have already taken action against offenders who haven’t complied with this legislation and will continue to take a tough stance against anyone who we believe is being reckless and irresponsible.
Farming vehicles should pull into lay-bys to let traffic pass during busy times, he said, and need to make sure their vehicles are clear of mud before hitting a public road.
Officers have also warned motorists to take extra care and avoid dangerous manoeuvres.