Abstract
The paper describes the methodology and preliminary results obtained from a study conducted at the University of California Berkeley PATH Program by a team of researchers from INRETS, Bron (France), The University of Technology Sydney and U.C. Berkeley, USA. The study intends to test network based cellular positioning methods to assess emergency calls management on national roads and motorways and to give travel times estimates on road segments from the current fleet of vehicle equipped with cell phones. The first results from a simulation work show that we can expect a good estimate of travel time from cell phones used as probe vehicles.