Use of travel demand satisfaction to assess road network reliability

A new concept of network reliability is introduced to assess the performance of the road network. It is referred to as the travel demand satisfaction reliability (DSR). In order to understand this new concept, the attributes to recurrent travel demand are firstly investigated for the analysis of road network reliability. The latent travel demand (LTD) is then distinguished and estimated by elastic travel demand functions. The ratio of the equilibrium travel demand and LTD can be used to ascertain the extent of satisfying and revealing the latent travel demand (DSI), which is affected by both the uncertainty of the network degradation and of the recurrent travel demand. The DSR is defined as the probability that the road network can accommodate a given DSI. The DSR can be extended to include other reliability measures such as travel time reliability under certain conditions. In order to facilitate the presentation of the essential ideas, simple examples are employed for discussion together with mathematical formulation.