Correct determination of deceleration is very important from the aspect of the investigation of traffic accidents, because deceleration of the vehicle involved in the traffic accident is of key importance for the preparation of a quality finding and opinion of traffic expert. In this paper it was conducted the investigation how the change of the pressure affects the change of the temperature of the brake couple and how this change is later reflected in the deceleration of the vehicle and the braking distance. In order to find how the temperature influences the deceleration, it was conducted experimental investigation. The experimental investigation was conducted on the experimental test rig, which simulates the braking process for the quarter of the vehicle mass, and the experimental investigation was conducted for four different braking pressures: 2 MPa, 3 MPa, 4 MPa, and 5 MPa. The temperature of the brake couple was measured during the entire braking process. Also the difference between mean fully developed deceleration and average vehicle deceleration is shown. It was found that for the case when the braking pressure was 5 MPa, the maximum deceleration value was greater than the value of gravity of Earth which may impair the stability of the vehicle. When the braking pressure was 2 MPa, 3 MPa, and 4 MPa, the temperature increased, respectively, but in the last measurement, when the braking pressure was 5 MPa, it began to decrease. Braking distance decreased with the increment of the braking pressure. Also, with the braking pressure increment, the deceleration increased in all cases.