Obtaining near real-time information of travel times is a critical element of most applications of intelligent transportation systems. The use of transit vehicles as probe vehicles for collecting travel time data for automobiles on urban corridors was examined. Because transit vehicles are increasingly equipped with an automated vehicle locator (AVL) for reporting the current location of the vehicle, it may be possible to use the AVL data for travel time purposes. In anticipation of such an application of AVL, the relationship between travel times of a transit vehicle and of an automobile is examined for stability of data and adjustment needs. Travel times of transit vehicles and automobiles were measured simultaneously along the same sections on major corridors in Delaware. The difference in travel times was relatively stable, and, hence, appropriate formulas for predicting the travel time of automobiles were developed. The model coefficients were found to be reasonable and stable for various traffic conditions. The study suggests that the AVL-equipped transit vehicle can be used as a probe vehicle to collect travel time data at regular intervals with minimum cost.