查看更多>>摘要：Driver distraction and lack of awareness of the driving situation are major causes of accidents in the urban areas in Taiwan; failing to obey traffic signals is the third leading accident cause. Numerous innovative in-vehicle information systems (IVIS) could be used collectively to provide drivers with a variety of information, such as messages from intersection collision warning systems (ICWS) by way of different in-vehicle interfaces. How the different IVIS interfaces influence driver workload and safety is always an important issue. This study investigates the effects of auditory ICWS messages on driver performance while the driver's visual, hearing, or mental processing attention resources (or all three) are engaged by secondary tasks. This type of engagement or distraction commonly occurs when a driver uses IVIS. The secondary tasks used to distract drivers were created by different types of mathematical questions presented with different types of display devices (e.g., voice from a speaker or numbers shown on a liquid crystal display screen or head-up display). Mixed linear models were employed to examine the factors influencing driver perception-reaction time with the consideration of repeated measures. Several factors, including several main factors and an interaction, were found to be significant. The most important finding was that the interaction between provision of ICWS information and the display format indicated that an auditory warning message could increase driver perception—reaction time while a driver was distracted by an auditory task. In addition, it was found that driver distraction due to different mental processing tasks had a significant impact on driver perception—reaction time.
查看更多>>摘要：The effects of human-machine interface (HMI) design for intelligent speed adaptation (ISA) on driving behavior and acceptance were measured in a moving-base research driving simulator. Sixty-four experienced drivers participated in two simulator experiments (32 in each). During the simulated runs with ISA, the speed limit was communicated through the ISA system. The ISA system consisted of an indication of the speed limit on the speedometer and a gas pedal that could be used either as a haptic or tactile pedal or as a dead throttle. Two versions of the haptic gas pedal were examined in Experiment Ⅰ: a low-force ISA (easy to overrule, informative in nature) and a high-force ISA (stronger counterforce, more compulsory in nature). Two other configurations were tested in Experiment Ⅱ: a tactile pedal (a vibration on the gas pedal, informative in nature) and a dead throttle (completely restraining the driver from exceeding the speed limit). It was hypothesized that the closer the ISA is to an informative type, the higher the acceptance and the smaller the effects on driving behavior would be. This hypothesis appeared to be valid, although for both driving behavior and acceptance, not all four HMIs could be ranked unambiguously on the scale from no ISA to full ISA. In sharp curves, drivers appeared to choose a driving speed below the speed limit, irrespective of ISA. The specific road environment scenarios that were inserted to examine presupposed compensatory behavior for experienced delay indicated no signs of compensatory driving behavior.
查看更多>>摘要：There is significant interest among traffic management personnel in the use of automated warning systems to provide drivers with real-time information on hazardous conditions related to traffic, limited visibility, or roadway obstructions. However, the effectiveness of such systems in achieving desired traffic safety improvements has not yet been well quantified. Relative influences on traffic safety can be assessed in many ways, and overall conclusions must be based on an appropriate set of metrics and methodologies for a particular implementation. This work, supported by the California Office of Traffic Safety and the California Department of Transportation (Caltrans), builds on prior research to develop, deploy, and test various metrics and methods to evaluate a large-scale real-time driver warning system, the Caltrans automated warning system, installed on Interstate 5 and State Route 120 near Stockton, California. Methods include the analysis of historical accident data over an 11-year period, a direct assessment of the operational behavior of the system correlated with accident data, and a study of the direct effects of real-time warning messages on driver behavior. Instrumentation deployed to facilitate these detailed analyses is described. The resultant body of data supports the correlation of measurable traffic flow parameters with relative traffic safety.
查看更多>>摘要：Current methods for evaluating the quality of service provided by a variable message sign (VMS) may not yield results that represent the satisfaction drivers experience because these techniques cannot represent the variability and complexity of human perception with great fidelity. To solve those problems, a new method that applies fuzzy set theory was developed. Results of a preexisting survey of VMS service quality were reanalyzed with this method. For this application, two membership functions were constructed with two different experimental methods: interval estimation and pairwise comparison. Specifically, construction of the second membership function used Saaty's eigenvector method. These two membership functions employ five linguistic statements to represent the degree of satisfaction and relative importance of six performance criteria. Quality of VMS service perceived by an individual driver was evaluated with the concept of the fuzzy weighted average. A set of 322 quality measures was computed, and they were aggregated and transformed into a single percentage value with the use of an arithmetic fuzzy mean.-The defuzzified final value indicates the degree of satisfaction with VMS service perceived by a group of participating drivers, taking into consideration the variance of human perception and the degree of importance of the six criteria. By employing the proposed method, the quality of VMS service as subjectively perceived by humans and influenced by various exogenous factors can be evaluated while still considering the subjective and complicated manner of human thinking.
查看更多>>摘要：Road authorities are under increasing pressure from advertisers to allow video advertising in the right-of-way but are understandably concerned about whether video signs constitute a driving hazard. At the City of Toronto's request, a comprehensive assessment of traffic safety impacts related to such signs was carried out in a series of studies involving three downtown intersections and an urban expressway site. An on-road eye fixation study was carried out to determine if drivers look at video advertising signs. Conflict studies were conducted to determine if there were more conflicts on intersection approaches with visible video signs than on those without such signs. A before-and-after sign installation study of headways and speeds on the urban expressway was carried out. Crashes were compared before and after sign installation at the expressway and three intersection sites. Finally, a public survey was conducted to determine if video advertising was perceived to affect traffic safety. On the basis of the eye fixation study and the public survey data, it is apparent that video advertising can distract drivers inappropriately and lead to individual crashes. However, the evidence from other studies was not consistent and suggests that for the particular signs studied, overall impacts on traffic safety are likely to be small. Further studies, especially prospective ones with larger crash data sets, are required to be certain about the findings. A comparison between this study and an earlier one suggests that there are large differences in driver distraction depending on the placement and the environment in which the sign is seen. Further studies are required to determine factors that minimize driver distraction.
查看更多>>摘要：A study on the message display formats of portable variable message signs (VMSs) is presented. Through a series of laboratory driving simulation experiments, the influences of the interaction between display format and number of message lines and driving lanes were investigated. In the simulation, digitally created VMS stimuli were inserted into a driver's-view driving video, and the video was projected onto a screen in front of a stationary vehicle. Eighteen subjects from three age groups with balanced gender participated in the experiments. Each subject, sitting in the driver's seat of the vehicle, was required to make proper responses signaling comprehension of the VMS stimuli. Subjects' responses and accuracy were recorded in a database. On the basis of the statistical analysis of the collected data, it was found that discretely displayed messages took less response tune than sequentially displayed messages. Single-line messages were better than multiple-line messages. Motorists could better view portable VMSs when they were driving in the outer lane. It was also found that older drivers exhibited slower response and less accuracy than younger drivers; women drivers exhibited slower response but higher accuracy than men drivers.
查看更多>>摘要：Deceleration characteristics of passenger cars are often used in traffic simulation, vehicle fuel consumption and emissions models, and intersection and deceleration-lane design. Most previous studies collected spot speed data with detectors or radar guns. Because of the limitations of the data collection methods, these studies could not determine when and where drivers began to decelerate. Therefore, the studies may not provide an accurate estimation of deceleration time and distance. Furthermore, most previous studies are based on outdated and limited data, and their conclusions may not be applicable to the current vehicle fleet and drivers. The normal deceleration behavior of current passenger vehicles is evaluated at stop sign-controlled intersections on urban streets on the basis of in-vehicle Global Positioning System data. This study determined that drivers with higher approach speeds decelerated over a longer time and distance. Higher initial deceleration rates were also associated with higher approach speeds. However, the collected data in this study did not indicate a clear relationship between the average and maximum deceleration rates and approach speeds. With second-by-second deceleration profile data, the authors found that most drivers reached their maximum deceleration rates about 5 s or less than 5 s before stopping, and the maximum deceleration rate (3.4 m/s~2) recommended by AASHTO was applicable to most of the study drivers. This review verified several previous deceleration models with the current observations and found that the polynomial model developed by Akcelik and Biggs provides the best fit for the data set in this study. Finally, this study developed a new deceleration model based on the approach speeds and deceleration time.
查看更多>>摘要：Driving simulator technology provides a safe method for evaluating the impact of vision loss on different components of the driving task and the potential efficacy of visual aids intended to compensate for a particular type of vision loss. Most previous investigations have used general driving scenarios. It is proposed here that scenarios with different task requirements be designed specifically to address the condition under investigation. As an example, the design of driving scenarios and tasks that are specific for the evaluation of one type of visual field loss, homonymous hemianopia, is described. Results of pilot studies show that even with a small sample size, the design is sufficiently sensitive to differentiate individuals with hemianopic visual field loss from control drivers. These results suggest that careful design of test situations, measurements, and analyses provides a strong basis for investigations of driving performance of individuals with specific types of vision impairment and could be used to evaluate the efficacy of low-vision driving aids.
查看更多>>摘要：The research project aimed at calibrating and validating the driving simulator of the European Interuniversity Research Center for Road Safety to enable its use for design and verification of the effectiveness of temporary traffic signs on highways. The research was developed through the following steps: (a) a survey of speed measurements on highways next to a work zone of medium duration, (b) reconstruction in virtual reality of the real situation by using the driving simulator and subsequent running of a series of driving tests, and (c) statistical analysis of the field speeds and of the speeds from driving simulations for validation of the simulator. The surveyed work zone was located on Highway A1 from Milan to Naples, Italy. Speed measurements were conducted with a laser speed meter in the transition area, the activity area, and the termination area, and in the advance warning area speeds were shot with a camera from an overpass. Speed data from the field and the simulator were analyzed by using the bilateral Z-test for non-matched samples to determine whether drivers responded differently in the simulator compared with their response during the real driving experience. The activity carried out revealed that differences between the speeds observed in the real situation and those measured with the simulator were not statistically significant.
查看更多>>摘要：Critical research needs associated with the effective application of visualization to transportation systems projects are identified. Visualization research needs are discussed within a broader, multidisciplinary context of technology development in the areas of simulation and modeling. Parallels are drawn between the current state of the practice in transportation as compared with that in the military-defense and aerospace areas. Some major differences between those areas and transportation systems development and user environments are noted, in particular (a) the current absence within the transportation community of a strong government research and development focal point for visual simulation and modeling and (b) the absence of an economic imperative similar to what prompted the defense community to embrace fully these technologies (i.e., fuel shortages, training system costs, and force readiness).
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