To accurately estimate road section travel time in small mountainous cities, the travel time modifica- tion model was proposed based on traffic property analysis, traditional BPR model analysis, as well as the accu- mulative traffic flow analysis of mixed traffic road sections. In this paper, the manual recording method was adopted to collect field data under non-congestion state, and VISSIM software was simulated to acquire experi- mental data under congestion state. Then, the traditional BPR model was modified based on a large amount of traffic flow data, and an error comparison between the traditional and modified BPR models was made. The re- search results show that the traditional and modified BPR models respectively produce the average errors of 35.021% and 4.597% in travel time for arterial roads, and of 46.737% and 3.120% in travel time for access roads. It can be concluded that the estimation performance of the modified BPR model is better than that of the traditional BPR model, and the effects of non-motor vehicle interference on access road travel time is more sig- nificant.