A traffic network with the following information structure is considered. The link travel times have probability distrbutions which are know from historical data. When the traveler arrives at a node, the actual travel times on the down streaming links are revealed to him. For given orign, destination, departure time and scheduled arrival time, the reliability of a routing strgetgly can be measured by the probability of arriving at destination before scheduled time. In this paper an algorithm is provided for generating a route by taking into account both the historical statistical infomation and real time information. The route generated has maximum probabilty of arriving at the destination before the scheduled time, under the adopted information structure..