A user interface for a traffic load simulator for a telecommunication system divides call traffic into sub-groups of call traffic that have a common characteristic. Such sub-groups may include rush hour callers, lunch time callers, teenagers, internet surfers, business customers and other background callers that do not fit into any one sub-group. Each sub-group is represented as a timeline on a display where the traffic for the sub-group is simulated with ramp up and decline rates corresponding to the rate at which calls are added to the system or disconnected from the system and steady state volume between the ramp up and decline, all as a function of time-of-day. The timelines may be manipulated by graphically changing the rates, steady state volume and time-of-day for the events. In this manner realistic traffic loads on the system may be simulated to determine times and nodes when and where the system may be overwhelmed.