During the acoustic emission (AE) monitoring of bridge, the AE signal we need can be easily masked by tire–road noise. To find out how much this noise affects the AE monitoring results of the bridge. In this study, controlled pass-by tests were carried out to collect the tire–road AE signals made by cars, buses, and heavy trucks with different speeds, where AE sensors are placed at multiple positions on the pavement and bottom deck of the bridge. In each case, the intensity and spectrum of AE noise were analyzed. Results show that the intensity of the tire–road AE noise increases with the speed, and the bandwidth of the main frequency increases slightly with the increasing speed. The peak frequency of the tire–road AE noise produced by the vehicles is approximately 2 kHz, and the AE energy distributes between 0 and 25 kHz. The proposed prediction method based on the characteristics of tire–road AE noise can effectively predict noise.