Method for estimating traffic state parameter based on confidence of speed of float car

The invention provides a method for estimating a traffic state parameter (speed) based on confidence optimization by analyzing data characteristic of the float car, introducing a confidence factor and mainly considering float car data sample number, the speed and time continuity of a traffic state. The average speed of the float car is estimated by confiding most of vehicles and high-speed vehicles and combining speed data of a previous time interval and historical speed data. The influence of abnormal data on a calculation result is effectively reduced, so that the calculation result is closer to an actual road situation; meanwhile, the problem of traffic state parameter estimation under the condition of sample size deficiency is solved, so that the accuracy and the stability of the traffic state parameter estimation are greatly improved.