A method for traffic impact analysis with pre-trip traffic information is presented

in which travellers'reactions to the traffic information are described by stochastic route choice models. Travellers are divided into two groups according to the information provision: the travellers who receive information will avoid the congested region when they making decisions

otherwise they follow the logit style stochastic route choice behavior. Traffic assignment algorithm for such mixed behaviours is proposed.The central business district

the Pearl River New Town in Guangzhou

China

is chosen to evaluate the impacts of traffic information.It is found that the inappropriate information has negative impact on road network

and more information does not guarantee improvements of the network. A discussion on the optimization of traffic information providing is presented.