If you ignored a summons requiring you to appear in court for failing to pay a traffic fine, the court may issue a warrant for your arrest for being in contempt of court.

Practical steps to follow:

1. If you do get stopped and they want to arrest you, demand to see a copy of the warrant. The police can only arrest you if they have the original or a copy of the warrant for your arrest on them.  (In terms of Section 45 of the Criminal Procedure Act an arrest on a copy or a written communication from a magistrate or peace officer is legal.).

2. A practical ruling by the Director of Public Prosecutions is that the Metro Police must supply the warrant of arrest or at least a copy of the warrant within 30 minutes after the arrest. It is impossible for the Metro Police to have 1, 5 million original warrants of arrest at the road block.
3. If the police cannot produce a copy of the warrant of arrest, refuse to go with them and point out that the arrest is illegal.

4. If they persist and still want to arrest you despite their inability to produce a copy of the warrant advise them that you will sue them for unlawful arrest. At that time, take down all the details of the arresting officers, and list the date and time of the arrest. Make a mental note of all the events and surrounding circumstances concerning the arrest and as soon as possible thereafter (whilst the events are still fresh in your mind) make a detailed statement.
5. Thereafter, take legal advice and if you are advised to do so, lay a charge against the police as soon as possible after the incident.

For a more detailed explanation, see http://www.bregmans.co.za/stopped-at-a-roadblock-what-are-your-rights/