Meeting national response time targets for priority 1 incidents in an urban emergency medical services system in South Africa: More ambulances won't help.

Background: Response time is viewed as a key performance indicator in most emergency medical services (EMS) systems.

Objective: To determine the effect of increased emergency vehicle numbers on response time performance for priority 1 incidents in an urban EMS system in Cape Town, South Africa, using discrete-event computer simulation.

Method: A simulation model was created, based on input data from part of the EMS operations.