The invention discloses a tunnel 
traffic accident duration prediction method based on PCA and 
Adaboost, and the method comprises the following steps: importing historical 
traffic accident data: carrying out the preprocessing of the data, and dividing the data into a short grade, a medium grade, a long grade and an extra-long grade according to the duration of an accident; carrying out the missing value checking and 
processing on input variables in the prediction model; and finally, carrying out thermal coding 
processing on the classification variables. Herein, the PCA method is used for decentralizing original input variables and calculating a 
covariance matrix of the original input variables, and feature values and feature vectors of the original input variables are calculated on the basis, and a plurality of feature values and corresponding feature vectors are sequentially determined from small to large. Firstly, 
traffic accident duration is classified based on a weak classifier, and a basic 
classification result is obtained through sample training; and then, an 
Adaboost iteration framework is adopted to calculate classification error samples of the weak classifier, the weight of the classification error samples is improved, a next weak classifier is constructed on this basis, and a final strong classifier is obtained after multiple iterations.