Kidnaps in urban areas can be planned or opportunistic. Planned kidnaps are usually carried out by professional criminal gangs for financial or political gain. They identify a potential victim and observe their routine/lifestyle for some time. They then abduct them where they are predictable, vulnerable and accessible, demand a substantial ransom and hold the victim for a considerable length of time.
Opportunistic kidnaps are usually express kidnaps carried out by street criminals. They often start out as a mugging and escalate into a kidnap situation when the mugger realises that you represent an opportunity to make significantly more money by way of a ransom.
Kidnaps in urban areas can be avoided by being aware and identifying unusual occurrences early on – such as new people or cars – and reporting them to police or security. A kidnapper planning to abduct you will have to be in the areas that you are frequenting regularly, so you will identify those people if you are actively looking for them.