Traveler information systems were created to serve drivers by providing accurate information about traffic and road conditions before drivers began their trip. The advancement of cellular telephones provided a new opportunity for drivers to access traffic and road information enroute, but introduced considerable cognitive distraction on drivers navigating the complex phone trees. The evolution of traveler information systems onto smartphone applications eased the cognitive demand previously imposed by phone tree systems, but shifted the demand to drivers’ visual resources. Manipulating a cell phone, for calling or texting, has been demonstrated to be hazardous to safe driving and consequently, has been made illegal in many states (e.g. Horrey & Wickens, 2004; Rakauskas, et al., 2005; Radeborg, Briem, & Hedman, 1999; Strayer, Drews, & Johnston, 2003). Public state traveler information applications have largely been created with the intent that drivers will only access the information “pre-trip” and not en-route. Unfortunately, some drivers will persist despite application warnings and will use smartphone applications while driving. This study investigates the current features of state and proprietary traveler information applications, elements of good design and usability, human factors issues regarding visual and cognitive distraction, and makes recommendations for the next generation of Minnesota’s traveler information application, MN 511. The dichotomy between state-funded 511 travel information applications and proprietary traveler information applications is primarily determined by the features each contains. The common features included in the current proprietary traveler information applications provide insight into the opportunities for future iterations of MN 511 mobile applications. The MN 511 application can continue to improve by incorporating select features from proprietary applications, such as voice commands, route guidance, saved places, and travel time estimates, while taking into account cognitive workload and visual distraction. This is important because publicly funded traveler information applications have a greater responsibility, compared to proprietary applications, to account for distraction and ensure the safety of its users. Good usability and a proper interface can be achieved by providing users with a) controls and displays that are highly visible and easily interpretable, b) internal consistency, c) an interface that is consistent with their convention and previous experiences, d) timely visual and auditory feedback, e) explicit messaging to help users recognize and correct the error, and f) control and freedom to undo incorrect actions. Features that improve usability and user’s trust in a system during pre-trip planning, using either a 511 application or navigation application, include presenting a route overview (ideally with a destination entry), the ability to remember the user’s preferences (e.g. layers or destinations), and providing users with all the available alternative routes and all the necessary information that the users will need to weigh these alternatives. Usability and user’s trust in a system providing en-route information can be increased by providing users with a) sufficient detail about the starting location/direction at the beginning of route guidance, b) the target address and an indication of whether the destination is on the left of right side of the road as driver approaches the destination, c) precise distance information, d) timely, brief and concise auditory turn-by-turn directions, e) auditory directions that are synced up with the visual display, f) a clutter free interface through layering, use of 2D maps as opposed to 3D maps, and labeling street names parallel with the street orientation, g) the benefits of a suggested detour, and e) timely rerouting guidance. However, these features are best implemented by integrating a 511 traveler information system with a navigation system. Visual distractions produce a larger decrement in driving performance than cognitive distractions, which are often imposed by auditory message, suggesting that re-design efforts should be first channeled towards reducing visual demand through usability standards and subsequently channeled toward reducing auditory demand. Cognitive distraction can also be potentially reduced by implementing a) a multimedia system that uses auditory presentations for alerting functions and visual display to present details of the turn and spatial information and b) a speech interface with high recognition rate. MN 511 currently includes many features which enable it to be competitive with other states; however, it lacks some of the more advanced features which today’s technology-savvy users come to expect. Recommendations for improvement include clutter reduction, reduction in visual distractions, customizable features (e.g. points of interest, favorite routes, and history of addresses and locations) and inclusion of route specific verbal information. Moving towards a multi-media system is highly encouraged. The overall recommendation, given the in-depth investigation into 511 and proprietary applications nationwide, is for Minnesota to integrate MN 511 with a low-distraction navigation system that would thereby reduce driver stress and convert to a text-to-speech based system to meet the needs of today’s drivers and result in higher user satisfaction. (Author/publisher)
Samenvatting