Abstract: Aiming at developing intelligent transportation system，a hybrid algorithm for traffic flow breakdown identification
based on fast Mallat algorithm and RBF network is presented utilizing the characteristic of traffic flow.Utilizing the association
between the wavelet coefficients and traffic flow，the set of approximate coefficients and detail coefficients of wavelet
decomposition from traffic flow parameters is regarded as the input of the Radial Basis Funtion（RBF） network.And the
state of traffic flow breakdown can be extracted from the RBF network.Traffic flow breakdown usually results from traffic
incidents，a performance test is carried out using data obtained from the simulation under the condition of incident and
non-incident.According to the results of test compared with other algorithms，the hybrid algorithm performs better than the
other algorithms in traffic flow breakdown identification.