The aim of the present study was to provide practical assistance to HGV drivers when reversing into a freight-handling bay. Too many serious and even fatal accidents occur during this maneuver and driving instructors themselves have no effective tool for assessing its performance.

Prior in-depth knowledge of driver-implemented maneuvering procedures is required to design an efficient form of assistance. Visual requirements form one of the most important factors for the work especially in relation to vehicle driving. Performance of this analysis has been possible through the use of an advanced data acquisition unit, CAPTIV, which allows the recorded image of the situation to be registered, analyzed and synchronized with each type of event reported through sensors or a visual behavior data entry keyboard.

Using a data entry keyboard, an experimenter sitting in the driving station passenger seat records the localization of the driver's look at four different zones of the visual field (at the same time, the driver is filmed by a dashboard-mounted mini video camera). However, for its interpretation, this parameter has to be related to other indicators connected with the situation under study. The angle of break between trailer and tractor unit was measured indirectly by a potentiometric sensor positioned as close as possible to the fifth wheel (part located between the trailer and the tractor unit, which ensures articulation of the vehicular combination).

The lorry trajectory is also identified by means of a mini video camera positioned at the rear top center of the semi-trailer, which records a rearward view from the semi-trailer and enables it to be localized with respect to marks on the ground.

The maneuver is considered to have started when the driver engages reverse gear and to have ended when the lorry comes to a halt. An attempt is counted when the lorry re-passes the parking line in forward after entering the parking line in reverse. Final position accuracy is evaluated by measuring the distances in centimeters between the obstacle(s) and the semi-trailer when the lorry has completed its "handling bay entry" maneuver.

Simply describing the procedures adopted by drivers has allowed identification of a number of the factors, which make the maneuver difficult. It has been possible to break the maneuver down into several stages which, when compared with HGV driving instruction strategies, will enable development of a maneuver teaching procedure and design of a reversing assistance system based on ultrasonic detection of obstacles with in-cab audio feedback.

The planned ensuing study will focus on analyzing changes in driver activity after introducing this reversing assistance system in the cab. The study will enable the approach aimed at understanding the perceptive and operating difficulties associated with the task to be supplemented to remedy these difficulties.

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