RESUMEN
Road geometric design is a fundamental factor that impacts driving speed. Previous research generally paid attentions to the influences of specific road characteristics (e.g. curvature) on driving behaviors. Limited studies have focused on how drivers identify different alignments and how they further take the varying speed choices. This study aims at filling the gap by investigating the subjective categorization of road alignments based on middle-aged driver groups. A total of sixteen participants with ages ranging from 23 to 40 years were recruited. Participants were first asked to undertake naturalistic driving tests on a four-lane divided mountainous freeway while photos of the road and the driving speed were collected. Participants were then asked to subjectively sort the photos of the road into piles, within each pile we considered their driving behaviors would be similar. Finally, questionnaire survey was conducted in terms of comfort, safety, speed choice and sight distance. The picture grouping revealed three distinct and non-overlapping subjective categories of road alignment. And driver's ratings about comfort and safety were significantly different between these categories. The category with the largest sight distance and highest speed choice turned out to have the lowest rating in comfort and safety (note that the rating scales for comfort and safety had reversed polarity such that low numbers indicated high comfort and high safety). Statistical evidences indicated that the drivers have developed underlying mental schema about road alignment. Therefore, their speed choices on combined alignment were further investigated. The difference between actual driving speed and driver's expected speed showed close relation to the ratings and significant difference between two of the categories. Road with large absolute value in speed difference informed inconsistency between geometric design and driver's expectation from the aspects of drivers' perception and expectation of the road. The findings provided insight into how middle-aged driver views and categorizes road alignment. And it was found that the drivers relied on visual characteristics of the alignment to distinguish the categories instead of separate horizontal and vertical geometric parameters. It was implied that more considerations should be taken into driver's perception of road during alignment design to improve road safety.
Asunto(s)
Conducción de Automóvil , Toma de Decisiones , Percepción/fisiología , Adulto , Entorno Construido , Femenino , Humanos , Masculino , Persona de Mediana Edad , Modelos Estadísticos , Medición de Riesgo , Seguridad , Encuestas y Cuestionarios , Adulto JovenRESUMEN
As drivers move through the road transport system they are exposed to a range of different situations and road conditions in a relatively short space of time. Drivers' expectations about what will happen on different types of roads have strong effects on their speed choices, and where they look and what they attend to. As a result it is important to assist drivers to change their expectations when they transition from one road type to another. In this experiment we investigated the effectiveness of different centreline road markings in preparing for a horizontal curve as drivers moved from a motorway to a two-lane rural country road. Fifty individuals were recruited to participate in a video-based simulated driving task to compare three centreline marking types in terms of their effects on speed choice and reactions to a driving hazard (horizontal curve). Although a complex marking previously associated with high risk produced the largest speed reductions during the transition from the motorway, it was the centreline more traditionally associated with rural country roads (dashed white centreline) that was associated with the best hazard reactions post-transition (brake reaction time and speed reduction before a horizontal curve). The findings demonstrated that the look of a road needs to convey a clear and unambiguous message to drivers. The transition to a two-star rural road is best achieved by making the road look like a typical two-star road as soon as possible.
Asunto(s)
Conducción de Automóvil/psicología , Planificación Ambiental , Directorios de Señalización y Ubicación , Accidentes de Tránsito/prevención & control , Adolescente , Adulto , Simulación por Computador , Femenino , Humanos , Masculino , Persona de Mediana Edad , Seguridad , Encuestas y Cuestionarios , Adulto JovenRESUMEN
The subjective categories that drivers use to distinguish between different road types have been shown to influence the speeds they choose to drive but as yet we do not understand the road features that drivers use to make their discriminations. To better understand how drivers describe and categorise the roads they drive, 55 participants were recruited to drive a video of familiar urban roads in a driving simulator at the speed they would drive these roads in their own cars (using the accelerator and brake pedal in the driving simulator to adjust their speed). The participants were then asked to sort photos of the roads they had just driven into piles so that their driving would be the same on all roads in one pile but different to the other piles. Finally, they answered a series of questions about each road to indicate what speed they would drive, the safe speed for the road, their speed limit belief as well as providing ratings of comfort, difficulty and familiarity. Overall, drivers' categorisation of roads was informed by a number of factors including speed limit belief, road features and markings (including medians), road width, and presence of houses, driveways and footpaths. The participants' categories were congruent with what they thought the speed limits were, but not necessarily the actual speed limits. Mismatches between actual speed limits and speed limit beliefs appeared to result from category-level expectations about speed limits that took precedence over recent experience in the simulator. Roads that historically had a 50km/h speed limit but had been reduced to 40km/h were still regarded as 50km/h roads by the participants, underscoring the point that simply posting a sign with a lower speed limit is not enough to overcome drivers' expectations and habits associated with the visual appearance of a road. The findings provided insights into how drivers view and categorise roads, and identify specific areas that could be used to improve speed limit credibility.