Both the prostitutes and the kerb-crawlers are committing criminal offences by carrying out these actions. You need to inform the police, obtaining as much information about the people involved, the names of those believe to be soliciting and the vehicle registration numbers of any suspected kerb-crawlers. However, do not put yourself at risk. If in doubt contact your nearest police station.
Warning letters, injunctions and prosecution are some of the tactics used by the police and other agencies in an attempt to combat this problem.