Driver’s distraction and its potential influence on the extension of reaction time

The driver's reaction time is one of the most important parameters for the road pre-accident analysis. There are known the results of tests, in which the value of this parameter was determined in expected and unexpected road situations. But in some cases, this time may be longer e.g. in situations in which the driver's attention may be distracted by keeping observations other than the area, in front of the car's surroundings. There are many manoeuvres, when the driver is obliged to observe many areas at the same time. Thus, his attention must be turned away from the main area – in front of the vehicle. The paper presents the results of tests involving the measurement of the driver's attention time focused on observing the surrounding other than the car's path. During the test, the driver's attention was focus on observing the side and back mirror, car radio and at the mobile phone. Certain values can be potentially considered as extending the typical driver's reaction time. The results of the presented tests have practical applications and can be used in the process of issuing opinions on traffic accidents.