The growing availability of in-vehicle technology to acquire and communicate information has proven to be advantageous for motorists. Mobile telephones allow motorists to maintain critical communication between personal and business contacts. Along with the advantages of in-vehicle information dissemination, the communication technologies and their user interfaces may have created a potentially unsafe environment for motorists. Several studies during the past decade have analysed the effects of using mobile telephones while driving. Results from these studies have indicated that the use of cell phones while driving, whether dialling, answering, or conducting mobile telephone calls, may add a significant increment of risk to the driving task. Studies have found that making a call during a trip may more than triple the risk of a crash. Recent studies have reported that hands-free cell phones have at least as great a risk factor as hand-held phones. It appears that the increased driving risk associated with cell phone use may be attributed primarily to cognitive and attentional factors rather than manual manipulation of the instrument. Recently many states have implemented a "Dial 511" traveller information system. This system allows motorists to conveniently obtain advanced information on road conditions, adverse weather, traffic incidents, and construction along their planned route by dialling 511 on their telephones. Providers of the 511 system have emphasized that drivers should obtain this information prior to departure or park their cars safely on the route to make the call. Many drivers, however, access the system to update their travel information while they are driving. No studies to date have examined the safety of using mobile telephones to acquire such travel information. The study referred to in this document analysed driving performance and situation awareness while subjects accessed the Montana Department of Transportation's 511 traveller information system via a cellular telephone. Data were collected using the Western Transportation Institute's Driving Simulation Laboratory. Performance on the primary tasks of driving (e.g., lane and speed maintenance) was found to be unaffected by interacting with the cell phone. Yet the tasks that require more prompt response times (e.g., avoiding collisions during unexpected conflicts) were degraded by the use of a cell phone, regardless of the type of instrument used. It appeared that drivers were less aware of their surroundings when interacting with the 511 traveller information system while using a cellular phone and driving. Drivers who communicated with 511 performed more poorly in recalling target objects in the environment than did their counterparts without communication tasks. This reduction in situation awareness could largely explain the increased braking responses and higher number of collisions.
Samenvatting