Based on analyzing the shortcoming of present traffic flow forecasting, the maximum
likelihood estimationwasused to forecastthe traffic flow ofroad sections. The essence of thismethod is
thatupstream observationalvariables in a successional time region are looked as explanatory variables,
and the maximum likelihood estimation is applied to seek the relationship between the observational
variables and the variables to be predicted to forecast the traffic flow of a road section. An example
shows that themaximum error rate between the forecasted and actual values of traffic flow is 5. 76%.