Effect of simulated visual impairment on nighttime driving performance

PURPOSE: This study investigated the effects of simulated visual impairment on nighttime driving performance and pedestrian recognition under real-road conditions. METHODS: Closed road nighttime driving performance was measured for 20 young visually normal participants (M = 27.5 +/- 6.1 years) under three visual conditions: normal vision, simulated cataracts, and refractive blur that were incorporated in modified goggles. The visual acuity levels for the cataract and blur conditions were matched for each participant. Driving measures included sign recognition, avoidance of low contrast road hazards, time to complete the course, and lane keeping. Pedestrian recognition was measured for pedestrians wearing either black clothing or black clothing with retroreflective markings on the moveable joints to create the perception of biological motion ("biomotion"). RESULTS: Simulated visual impairment significantly reduced participants' ability to recognize road signs, avoid road hazards, and increased the time taken to complete the driving course (p < 0.05); the effect was greatest for the cataract condition, even though the cataract and blur conditions were matched for visual acuity. Although visual impairment also significantly reduced the ability to recognize the pedestrian wearing black clothing, the pedestrian wearing "biomotion" was seen 80% of the time. CONCLUSIONS: Driving performance under nighttime conditions was significantly degraded by modest visual impairment; these effects were greatest for the cataract condition. Pedestrian recognition was greatly enhanced by marking limb joints in the pattern of "biomotion," which was relatively robust to the effects of visual impairment.

Prospective bus rapid transit scenarios for pilot corridor in Dhaka

Dhaka doesn’t have a mature transport system. Lacking in institutional arrangements, policy and planning, and law enforcement, the transport system operates has developed ad hoc and is situationally problematic. Absence of proper coordination between modes, poor public transport system, inadequate pedestrian facilities, and environmental degradation justify full consideration of Bus Rapid Transit (BRT) in Dhaka. BRT centres on sustainable transport principles. BRT is a system, which is capable to mitigate Dhaka’s transport problem if properly planned. In Strategic transport plan of Dhaka three BRT transport corridor has been proposed and BRT pre-feasibility study came up with one pilot corridor for early implementation of BRT. This paper first reviews international best practices then explores various BRT system packages and evaluates the suitability of these BRT packages by analyzing current bus service condition and physical and geometric configuration along the BRT pilot corridor. It concludes by proposing some BRT scenarios, which can be considered for further evaluation with respect to speed, delay, travel time and environmental pollution.

Review : Surfers Paradise foreshore redevelopment masterplan - urban plaza zone

The Centre for Subtropical Design has prepared this submission to assist the Gold Coast City Council to finalise a plan and detailed design guidelines for the Urban Plaza Zone of Surfers Paradise Foreshore Redevelopment Masterplan which will create a public open space ‘alive’ with the quality appropriate to a place which is both a local centre and an international destination. This review has been informed by the two over-arching values identified as characteristics of a subtropical place and people’s connection to it:  A sense of openness and permeability, and  Engagement with the natural environment. The existing qualities of the foreshore area proposed as the Urban Plaza Zone, reflect these subtropical place values, and are integral to the Surfers Paradise identity:  Seamless visual and spatial access to the beach and sea,  Permeable interface between beach and built zones provided by beach planting and shade to sand by Pandanus,  A shade zone mediating beach and linear promenade, road and commercial zones, enabling a variety of social and visual experiences, on soft and hard finishes, and  A lively, constantly moving shared road and pedestrian way catering for events and day to day activities with visual access to beach and shaded areas. The Centre for Subtropical Design commends the Gold Coast City Council on preparing a plan for a public open space that is a contemporary departure from the adhoc basis of development that has occurred, in that it will make this area more accessible. However, the proposed plan seems to be working too hard in terms of ‘program’. While providing an identifiable interruption in the linear extent of the Foreshore, the lack of continuity of design in terms of both hardscaping (such as perpendicular paving elements) and softscaping (such as tree selections) may contribute to a lack of definition for the entire Foreshore as a place that mediates, along its length, between sea and land. Providing a hard edge to a beach character of soft and planted transitional elements needs to balance the proposed visual and physical barrier with the need for perceived and actual easy access. The Surfers Paradise identity needs strengthening through attention to planting for shade, materials, particularly selection of paving colours, and stronger delineation of the linear nature of the Foreshore. The Urban Plaza zone is an appropriate interruption to the continuous planting, however the link from the commercial zone overtakes the public and beach zone. A more seamless transition from shop to sea, better integration of the roadway and pedestrian zone and improved physical transition from concrete to sand is recommended. Built form solutions must be robust and designed with the subtropical design principles and the Surfers Paradise identity as underpinning parameters for a lasting and memorable public open space.

Human-body shadowing effects on indoor MIMO-OFDM channels at 5.2 GHz

Pedestrian movement is known to cause significant effects on indoor MIMO channels. In this paper, a statistical characterization of the indoor MIMO-OFDM channel subject ot pedestrian movement is reported. The experiment used 4 sending and 4 receiving antennas and 114 sub-carriers at 5.2 GHz. Measurement scenarios varied from zero to ten pedestrians walking randomly between transmitter (tx) and receiver (Rx) arrays. The empirical cumulative distribution function (CDF) of the received fading envelope fits the Ricean distribution with K factors ranging from 7dB to 15 dB, for the 10 pedestrians and vacant scenarios respectively. In general, as the number of pedestrians increase, the CDF slope tends to decrease proportionally. Furthermore, as the number of pedestrians increase, increasing multipath contribution, the dynamic range of channel capacity increases proportionally. These results are consistent with measurement results obtained in controlled scenarios for a fixed narrowband Single-Input Single-Output (SISO) link at 5.2 GHz in previous work. The described empirical characterization provides an insight into the prediction of human-body shadowing effects for indoor MIMO-OFDM channels at 5.2 GHz.

A probability-based approach for assessing the relationship between crash accidents and pavement properties

Skid resistance is a condition parameter characterising the contribution that a road makes to the friction between a road surface and a vehicle tyre. Studies of traffic crash histories around the world have consistently found that a disproportionate number of crashes occur where the road surface has a low level of surface friction and/or surface texture, particularly when the road surface is wet. Various research results have been published over many years and have tried to quantify the influence of skid resistance on accident occurrence and to characterise a correlation between skid resistance and accident frequency. Most of the research studies used simple statistical correlation methods in analysing skid resistance and crash data.----- ------ Preliminary findings of a systematic and extensive literature search conclude that there is rarely a single causation factor in a crash. Findings from research projects do affirm various levels of correlation between skid resistance and accident occurrence. Studies indicate that the level of skid resistance at critical places such as intersections, curves, roundabouts, ramps and approaches to pedestrian crossings needs to be well maintained.----- ----- Management of risk is an integral aspect of the Queensland Department of Main Roads (QDMR) strategy for managing its infrastructure assets. The risk-based approach has been used in many areas of infrastructure engineering. However, very limited information is reported on using risk-based approach to mitigate crash rates related to road surface. Low skid resistance and surface texture may increase the risk of traffic crashes.----- ----- The objectives of this paper are to explore current issues of skid resistance in relation to crashes, to provide a framework of probability-based approach to be adopted by QDMR in assessing the relationship between crash accidents and pavement properties, and to explain why the probability-based approach is a suitable tool for QDMR in order to reduce accident rates due to skid resistance.

Check-in processing : simulation of passengers with advanced traits

In order to tackle the growth of air travelers in airports worldwide, it is important to simulate and understand passenger flows to predict future capacity constraints and levels of service. We discuss the ability of agent-based models to understand complicated pedestrian movement in built environments. In this paper we propose advanced passenger traits to enable more detailed modelling of behaviors in terminal buildings, particularly in the departure hall around the check-in facilities. To demonstrate the concepts, we perform a series of passenger agent simulations in a virtual airport terminal. In doing so, we generate a spatial distribution of passengers within the departure hall to ancillary facilities such as cafes, information kiosks and phone booths as well as common check-in facilities, and observe the effects this has on passenger check-in and departure hall dwell times, and facility utilization.

Walking when intoxicated : an investigation of the factors which influence individuals' drink walking intentions

Annually, in Australia, 10-15% of all road-related fatalities involve pedestrians. Of those pedestrians fatally injured, approximately 45% were walking while intoxicated or 'drink walking'. Drink walking is increasing in prevalence and younger persons may be especially prone to engage in this behaviour and, thus, are at heightened risk of being injured or killed. Presently, limited research is available regarding the factors which influence individuals to drink walk. This study explored young people's (17-25 years) intentions to drink walk, using an extended Theory of Planned Behaviour (TPB). Participants (N = 215), completed a self-report questionnaire which assessed the standard TPB constructs (attitude, subjective norm, perceived behavioural control) as well as the extended constructs of risk perception, anticipated regret, and past behaviour. It was hypothesised that the standard TPB constructs would significantly predict individuals' reported intentions to drink walk and that the additional constructs would predict intentions over and above the TPB constructs. The TPB variables significantly predicted 63.2% of the variance in individuals' reported intentions to drink walk, and the additional variables, combined, explained a further 6.1% of the variance. Of the additional constructs, anticipated regret and past behaviour, but not risk perception, were significant predictors of drink walking intentions. As one of the first studies to provide a theoretically-based investigation of factors influencing individuals' drink walking intentions, the current study's findings have potentially significant implications for understanding young people's decisions to drink walk and the design of future countermeasures to ultimately reduce this behaviour.

Quantification of particle emission characteristics and development of an emission model for use in transport microenvironments affected by traffic emissions

Vehicle emitted particles are of significant concern based on their potential to influence local air quality and human health. Transport microenvironments usually contain higher vehicle emission concentrations compared to other environments, and people spend a substantial amount of time in these microenvironments when commuting. Currently there is limited scientific knowledge on particle concentration, passenger exposure and the distribution of vehicle emissions in transport microenvironments, partially due to the fact that the instrumentation required to conduct such measurements is not available in many research centres. Information on passenger waiting time and location in such microenvironments has also not been investigated, which makes it difficult to evaluate a passenger’s spatial-temporal exposure to vehicle emissions. Furthermore, current emission models are incapable of rapidly predicting emission distribution, given the complexity of variations in emission rates that result from changes in driving conditions, as well as the time spent in driving condition within the transport microenvironment. In order to address these scientific gaps in knowledge, this work conducted, for the first time, a comprehensive statistical analysis of experimental data, along with multi-parameter assessment, exposure evaluation and comparison, and emission model development and application, in relation to traffic interrupted transport microenvironments. The work aimed to quantify and characterise particle emissions and human exposure in the transport microenvironments, with bus stations and a pedestrian crossing identified as suitable research locations representing a typical transport microenvironment. Firstly, two bus stations in Brisbane, Australia, with different designs, were selected to conduct measurements of particle number size distributions, particle number and PM2.5 concentrations during two different seasons. Simultaneous traffic and meteorological parameters were also monitored, aiming to quantify particle characteristics and investigate the impact of bus flow rate, station design and meteorological conditions on particle characteristics at stations. The results showed higher concentrations of PN20-30 at the station situated in an open area (open station), which is likely to be attributed to the lower average daily temperature compared to the station with a canyon structure (canyon station). During precipitation events, it was found that particle number concentration in the size range 25-250 nm decreased greatly, and that the average daily reduction in PM2.5 concentration on rainy days compared to fine days was 44.2 % and 22.6 % at the open and canyon station, respectively. The effect of ambient wind speeds on particle number concentrations was also examined, and no relationship was found between particle number concentration and wind speed for the entire measurement period. In addition, 33 pairs of average half-hourly PN7-3000 concentrations were calculated and identified at the two stations, during the same time of a day, and with the same ambient wind speeds and precipitation conditions. The results of a paired t-test showed that the average half-hourly PN7-3000 concentrations at the two stations were not significantly different at the 5% confidence level (t = 0.06, p = 0.96), which indicates that the different station designs were not a crucial factor for influencing PN7-3000 concentrations. A further assessment of passenger exposure to bus emissions on a platform was evaluated at another bus station in Brisbane, Australia. The sampling was conducted over seven weekdays to investigate spatial-temporal variations in size-fractionated particle number and PM2.5 concentrations, as well as human exposure on the platform. For the whole day, the average PN13-800 concentration was 1.3 x 104 and 1.0 x 104 particle/cm3 at the centre and end of the platform, respectively, of which PN50-100 accounted for the largest proportion to the total count. Furthermore, the contribution of exposure at the bus station to the overall daily exposure was assessed using two assumed scenarios of a school student and an office worker. It was found that, although the daily time fraction (the percentage of time spend at a location in a whole day) at the station was only 0.8 %, the daily exposure fractions (the percentage of exposures at a location accounting for the daily exposure) at the station were 2.7% and 2.8 % for exposure to PN13-800 and 2.7% and 3.5% for exposure to PM2.5 for the school student and the office worker, respectively. A new parameter, “exposure intensity” (the ratio of daily exposure fraction and the daily time fraction) was also defined and calculated at the station, with values of 3.3 and 3.4 for exposure to PN13-880, and 3.3 and 4.2 for exposure to PM2.5, for the school student and the office worker, respectively. In order to quantify the enhanced emissions at critical locations and define the emission distribution in further dispersion models for traffic interrupted transport microenvironments, a composite line source emission (CLSE) model was developed to specifically quantify exposure levels and describe the spatial variability of vehicle emissions in traffic interrupted microenvironments. This model took into account the complexity of vehicle movements in the queue, as well as different emission rates relevant to various driving conditions (cruise, decelerate, idle and accelerate), and it utilised multi-representative segments to capture the accurate emission distribution for real vehicle flow. This model does not only helped to quantify the enhanced emissions at critical locations, but it also helped to define the emission source distribution of the disrupted steady flow for further dispersion modelling. The model then was applied to estimate particle number emissions at a bidirectional bus station used by diesel and compressed natural gas fuelled buses. It was found that the acceleration distance was of critical importance when estimating particle number emission, since the highest emissions occurred in sections where most of the buses were accelerating and no significant increases were observed at locations where they idled. It was also shown that emissions at the front end of the platform were 43 times greater than at the rear of the platform. The CLSE model was also applied at a signalled pedestrian crossing, in order to assess increased particle number emissions from motor vehicles when forced to stop and accelerate from rest. The CLSE model was used to calculate the total emissions produced by a specific number and mix of light petrol cars and diesel passenger buses including 1 car travelling in 1 direction (/1 direction), 14 cars / 1 direction, 1 bus / 1 direction, 28 cars / 2 directions, 24 cars and 2 buses / 2 directions, and 20 cars and 4 buses / 2 directions. It was found that the total emissions produced during stopping on a red signal were significantly higher than when the traffic moved at a steady speed. Overall, total emissions due to the interruption of the traffic increased by a factor of 13, 11, 45, 11, 41, and 43 for the above 6 cases, respectively. In summary, this PhD thesis presents the results of a comprehensive study on particle number and mass concentration, together with particle size distribution, in a bus station transport microenvironment, influenced by bus flow rates, meteorological conditions and station design. Passenger spatial-temporal exposure to bus emitted particles was also assessed according to waiting time and location along the platform, as well as the contribution of exposure at the bus station to overall daily exposure. Due to the complexity of the interrupted traffic flow within the transport microenvironments, a unique CLSE model was also developed, which is capable of quantifying emission levels at critical locations within the transport microenvironment, for the purpose of evaluating passenger exposure and conducting simulations of vehicle emission dispersion. The application of the CLSE model at a pedestrian crossing also proved its applicability and simplicity for use in a real-world transport microenvironment.

Using reflective clothing to enhance the conspicuity of bicyclists at night

Bicycling at night is more dangerous than in the daytime and poor conspicuity is likely to be a contributing factor. The use of reflective markings on a pedestrian’s major joints to facilitate the perception of biological motion has been shown to greatly enhance pedestrian conspicuity at night, but few corresponding data exist for bicyclists. Twelve younger and twelve older participants drove around a closed-road circuit at night and indicated when they first saw a bicyclist who wore black clothing either alone, or together with a reflective bicycling vest, or a vest plus ankle and knee reflectors. The bicyclist pedaled in place on a bicycle that had either a static or flashing light, or no light on the handlebars. Bicyclist clothing significantly affected conspicuity; drivers responded to bicyclists wearing the vest plus ankle and knee reflectors at significantly longer distances than when the bicyclist wore the vest alone or black clothing without a vest. Older drivers responded to bicyclists less often and at shorter distances than younger drivers. The presence of a bicycle light, whether static or flashing, did not enhance the conspicuity of the bicyclist; this may result in bicyclists who use a bicycle light being overconfident of their own conspicuity at night. The implications of our findings are that ankle and knee markings are a simple and very effective approach for enhancing bicyclist conspicuity at night.

No longer Singaporean : visibilising the everyday contestations of identities

In the past decade or so, the citizens of Singapore have been vigorously urged by the state to turn their cultural and linguistic affinities with China to economic advantage. At the same time, the city-state has opened its doors to selected, skilled migrants from Asia including many of those from mainland and Greater China. These concurrent emphases have coincided with the trend and growing numbers of Singaporeans heading overseas for one reason or another. Through a reflexive journey sparked by a recent visit, I argue in this paper that the resultant change in the makeup of its population produces tensions that may well have important repercussions for a nation that is constitutionally multiethnic though pragmatically meritocratic. However, because these frictions find form only in everyday, pedestrian practices, they are often dismissed or ignored. It is my contention that as the stage on which innocuous, creeping shifts in social identities are enacted, finessed and (re)embedded into social imaginaries, these everyday contestations of identities need to studied for indications of what is at stake.

Acoustic hazard detection for pedestrians with obscured hearing

Pedestrians’ use of mp3 players or mobile phones can pose the risk of being hit by motor vehicles. We present an approach for detecting a crash risk level using the computing power and the microphone of mobile devices that can be used to alert the user in advance of an approaching vehicle so as to avoid a crash. A single feature extractor classifier is not usually able to deal with the diversity of risky acoustic scenarios. In this paper, we address the problem of detection of vehicles approaching a pedestrian by a novel, simple, non resource intensive acoustic method. The method uses a set of existing statistical tools to mine signal features. Audio features are adaptively thresholded for relevance and classified with a three component heuristic. The resulting Acoustic Hazard Detection (AHD) system has a very low false positive detection rate. The results of this study could help mobile device manufacturers to embed the presented features into future potable devices and contribute to road safety.

Opinions, attitudes and driving experiences of car and racing "enthusiasts" : results of the Ontario Car and Racing Club Survey

In recent years, car club and racing websites and forums have become an increasingly popular way for car enthusiasts to access racing and car club news, chat-rooms and message boards. However, no North American research has been found that has examined opinions and driving experiences of car and racing enthusiasts. The purpose of this study was to examine car club members’ opinions about and experiences with various aspects of driving, road safety and traffic legislation, with a particular focus on street racing. A web-based questionnaire (Survey Monkey) was developed using the expert panel method and was primarily based on validated instruments or questions that were developed from other surveys. The questionnaire included: 1) driver concerns regarding traffic safety issues and legislation; 2) attitudes regarding various driving activities; 3) leisure-time activities, including club activities; 4) driving experiences, including offences and collisions; and 5) socio-demographic questions. The survey was pre- tested and piloted. Electronic information letters were sent out to an identified list of car clubs and forums situated in southern Ontario. Car club participants were invited to fill out the questionnaire. This survey found that members of car clubs share similar concerns regarding various road safety issues with samples of Canadian drivers, although a smaller percentage of car club members are concerned about speeding-related driving. Car club members had varied opinions regarding Ontario’s Street Racers, Stunt and Aggressive Drivers Legislation. The respondents agreed the most with the new offences regarding not sitting in the driver’s seat, having a person in the trunk, or driving as close as possible to another vehicle, pedestrian or object on or near the highway without a reason. The majority disagreed with police powers of impoundment and on-the-spot licence suspensions. About three quarters of respondents reported no collisions or police stops for traffic offences in the past five years. Of those who had been stopped, the most common offence was reported as speeding. This study is the first in Canada to examine car club members’ opinions about and experiences with various aspects of driving, road safety and traffic legislation. Given the ubiquity of car clubs and fora in Canada, insights on members’ opinions and practices provide important information to road safety researchers.

Even moderate visual impairments degrade drivers’ ability to see pedestrians at night

Purpose: To determine the effect of moderate levels of refractive blur and simulated cataracts on nighttime pedestrian conspicuity in the presence and absence of headlamp glare. Methods: The ability to recognize pedestrians at night was measured in 28 young adults (M=27.6 years) under three visual conditions: normal vision, refractive blur and simulated cataracts; mean acuity was 20/40 or better in all conditions. Pedestrian recognition distances were recorded while participants drove an instrumented vehicle along a closed road course at night. Pedestrians wore one of three clothing conditions and oncoming headlamps were present for 16 participants and absent for 12 participants. Results: Simulated visual impairment and glare significantly reduced the frequency with which drivers recognized pedestrians and the distance at which the drivers first recognized them. Simulated cataracts were significantly more disruptive than blur even though photopic visual acuity levels were matched. With normal vision, drivers responded to pedestrians at 3.6x and 5.5x longer distances on average than for the blur or cataract conditions, respectively. Even in the presence of visual impairment and glare, pedestrians were recognized more often and at longer distances when they wore a “biological motion” reflective clothing configuration than when they wore a reflective vest or black clothing. Conclusions: Drivers’ ability to recognize pedestrians at night is degraded by common visual impairments even when the drivers’ mean visual acuity meets licensing requirements. To maximize drivers’ ability to see pedestrians, drivers should wear their optimum optical correction, and cataract surgery should be performed early enough to avoid potentially dangerous reductions in visual performance.

Evaluation of the skills for preventing injury in youth program : impact on health risk behaviors, injury and school connectedness

Injury is the leading cause of death among young people, and involvement in health risk behaviors, such as alcohol use and transport-related risks, is related to increased risk for injury. Effective health promotion programs for adolescents focus on multiple levels, including relationships with peers and parents, student knowledge, behavior and attitudes, and school-level factors such as school connectedness. This study describes the pilot evaluation of a comprehensive, multi-level injury prevention program for 13-14 year old adolescents, targeting change in injury associated with transport and alcohol risks. The program, called Skills for Preventing Injury in Youth (SPIY), incorporates two primary elements: an 8-week, teacher delivered attitude and behavior change curriculum with peer protection and first aid messages; and professional development for program teachers focusing on strategies to increase students’ connectedness to school. Five Australian high schools were recruited for the pilot evaluation research, with three being assigned to receive intervention components and two assigned as curriculum-as-usual controls. In the intervention schools, 118 Year 8 students participated in surveys at baseline, with 105 completing surveys at follow up, six months following the intervention. In the control schools, 196 Year 8 students completed surveys at baseline and 207 at follow up. Survey measures included self-reported injury, risk taking behavior and school connectedness. Results showed that students in the control schools were significantly more likely to report riding bikes without helmets, riding with dangerous drivers, having driven cars on the road, and using alcohol six months after the program, while the intervention group showed no such increase in these behaviors. Additionally, students in the control schools were significantly more likely to report having had pedestrian-related injuries at follow up than they were at the baseline measurement, while intervention school students showed no change. There was also a trend observed in terms of a decrease in bicycle related injuries among intervention school students, compared with a slight increasing trend in bicycle injuries among control students. Overall, scores on the school connectedness scale decreased significantly from baseline to follow up for both intervention and control students, however measurement limitations may have impacted on results relating to students’ connectedness. Overall, the SPIY program has shown promising results in regards to prevention of students’ health risk behavior and injuries. Evidence suggests that the curriculum component was important; however there was limited evidence to suggest that teacher training in school connectedness strategies contributed to these promising results. While school connectedness may be an important factor to target in risk and injury prevention programs, programs may need to incorporate whole-of-school strategies or target a broader range of teachers than were selected for the current research.

Severity of driver injury and vehicle damage in traffic crashes at intersections: A Bayesian hierarchical analysis

Most crash severity studies ignored severity correlations between driver-vehicle units involved in the same crashes. Models without accounting for these within-crash correlations will result in biased estimates in the factor effects. This study developed a Bayesian hierarchical binomial logistic model to identify the significant factors affecting the severity level of driver injury and vehicle damage in traffic crashes at signalized intersections. Crash data in Singapore were employed to calibrate the model. Model fitness assessment and comparison using Intra-class Correlation Coefficient (ICC) and Deviance Information Criterion (DIC) ensured the suitability of introducing the crash-level random effects. Crashes occurring in peak time, in good street lighting condition, involving pedestrian injuries are associated with a lower severity, while those in night time, at T/Y type intersections, on right-most lane, and installed with red light camera have larger odds of being severe. Moreover, heavy vehicles have a better resistance on severe crash, while crashes involving two-wheel vehicles, young or aged drivers, and the involvement of offending party are more likely to result in severe injuries.