The aim of thi s study was to investigate the influences of road surroundings on the relations between drivers' evaluations of risks and their behaviors.　A driving simulator was used in this study to simulate two different road surroundings: road with good visibility and residential road.　The author also examined the effects of the participants' prior experience of driving in a road surrounding with good visibility on their risk evaluations and behaviors in a residential one, and vice versa.　Ten participants were asked to follow the lead vehicle as their daily ways of driving in the simulator.　The participants were also instructed to evaluate the risks of each road surrounding and to avoid a crash in the simulated scenarios.　It was found that the participants' prior experience of either surrounding had no effects on their risk perceptions and behaviors in the other.　Most importantly, the result also showed that the correlations between the drivers' risk perceptions and behaviors were higher for the road surroundings with good visibility, while those for residential surroundings were lower.　The results may suggest that driving aptitude tests should include easy driving situations such as a road surrounding with good visibility to detect potential reckless drivers.

In a previous study that used eye tracking devices, accident repeaters exhibited significantly delayed detection of hazards.　However, it is necessary to develop a more low-cost method to diagnose more drivers.　In this study, we tried to obtain the same result as in the previous study without using eye tracking devices.　We developed a system for diagnosing hazard detection delays using a general-purpose computer, touch-panel display, and dedicated software.　Thirty photos of traffic scenes acquired from near the driver's seat were used as stimuli.　Twenty-five taxi drivers were required to touch the hazards in photos displayed on a touch panel.　The result revealed that first touch of accident repeaters was significantly delayed relative to that of safe drivers.　Accident repeaters touched significantly fewer potential hazards than safe drivers within two seconds from start to display stimulus than did safe drivers, but the number of obvious hazards was the same.　Touch timing of accident repeaters for a few hazards was significantly slower than that of safe drivers.　These results were almost the same as in the previous study that used eye tracking devices.