A model for average travel time estimation on signalized urban networks by integrating cumulative plots with probe vehicle information is presented. The integration is performed with the aim to reduce the relative deviations in the cumulative plots occurred due to mid-link sources/sinks. During under-saturated traffic conditions, concept of virtual probe is introduced and the accurate travel time can be obtained even with unavailability of real probe. For saturated and over-saturated traffic conditions and travel time estimation interval of 360 seconds: only one probe per estimation interval or 3% of vehicles traversing the link as probes has the potential to provide accurate travel time.