Investigating Cognitive Maps of Drivers with Color Vision Deficiency to Support Cartographic Design of Car Navigation Systems
1Pugliesi, E.; 2Moretti, A.; 3Ramos, A.P.; 4Vilma, T.
Driving in an unfamiliar area is one of the most demanding cognitive activities for drivers. Car Navigation Systems (CNS) support drivers with navigational instructions, including landmarks. Landmarks may play a key role in structuring the spatial information to form a cognitive map. They are potential navigational cues for drivers when following a route. A number of studies have suggested guidelines to include specific landmarks within car navigation systems to increase system usability in terms of efficiency, effectiveness and satisfaction of the system for users. A number of studies have indicated that CNS presenting ‘good landmarks’ can improve driver safety and performance. Traffic light has been proposed as the most effective and valued followed by bridge over road. However, until now we have not found similar studies conducted with drivers with color vision deficiency (CVD). Color vision deficiency affects approximately 8% of males and 0.4% of females. Although Brazilian law restrict driver’s license (“Candidates for vehicle driving must be able to identify green, yellow and red colors”), a high number of Brazilian people with CVD have driver’s license and are regular drivers. This research work investigates cognitive maps in the matter of using landmarks by drivers with CVD. A group of 20 male with normal color vision (NCV) and 15 male with CVD participated in this experiment. Ishihara test was applied to confirm CVD. All of them were regular drivers and had good knowledge of the city. Both group constructed map sketches of routes for a driver unfamiliar with the area, by considering a origin and destination. From a range of landmarks used by people with NCV, some elements and their frequency were traffic lights (12), hospital (7), park (5), gas station (3), Olympic center (5), hotel (3) and bridge over road (4). Taking into account the frequency of landmarks used by drivers with CVD, the most relevant to compare with NCV were hospital (9), park (7), Olympic center, hotel and bridge over road (4), traffic light (2) and gas station (1). Non-parametrical statistical analyses were conducted using confidence level of 95%. Fisher's exact test was used to compare the frequency of using landmarks between the two groups of drivers. Results indicate that traffic lights are much less used for people with CVD than NCV (p=.037). Results also showed there was a trend for drivers with CVD using more hospital than NCV (p=.080). On the other hands, gas station (p=1.0), bridge over road (p=.68), Olympic center (p=1.0), park (p=.14) and hotel (p=.39) did not present significant difference in the use for both groups. To identify if landmarks were used in the same proportion by drivers with CVD, Cochran’ test was performed. Results revealed that all landmarks were not used in the same proportion and that hospital and park had a trend to be the most used (p=.08). Besides, by using a scale from 1 to 9, some visual attributes allowed us to understand what may constitute a ‘good landmark’ for drivers with CVD. The visual attributes and their weighted medium scored for landmarks were color (5.67), shape (5.49), facade area (5.81), visibility (6.75), texture (4.63), permanence (8.67), notability (7.81), predictability in location (6.16), familiarity (7.02), predictability in appearance (7.12), uniqueness (7.04). We conclude that drivers with CVD used traffic lights much less than drivers with NCV as cue for route following information. On the other hand, bridge over road was used in the same proportion for both groups. Drivers having deficiency in color vision seem to give more value in permanence and notability attributes. Cartographic design of CNS for drivers with CVD should consider these implications. Finally, discussions are detailed, recommendations for future researches are suggested, and limitations of this work are pointed out.
Car navigation system; Cognitive maps; Color-blindness