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Qu X.,Griffith University | Yang Y.,Australian Institute of Psychology | Liu Z.,Monash University | Jin S.,Zhejiang University | Weng J.,Beijing Jiaotong University
Safety Science | Year: 2014

Objective: This paper aims to assess the potential crash risks across different traffic lanes (shoulder lane, median lane, and middle lane) near to ramps (before on-ramps, between ramps, and after off-ramps). Methods: Field data are collected at seven locations (90. min for each location) during peak hours. Two risk indices based on time to collision, individual risk and societal risk are proposed to represent the distinct interpretations of risks to transport agencies and individual motorists. One-way ANOVA is applied to analyze the risk impact of ramps in various types of locations across distinct traffic lanes. Results: Median lanes and sections after off-ramps have relatively lower risks compared to other lanes and sections. The individual and societal risks might not always be consistent since the two risk indices are proposed based on distinct perspectives: transport agencies focus on the crash/conflict frequencies in a road section and individual motorists concern more about the probability of being involved in a crash/conflict during their journey. Conclusions: The differences in risks mainly result from the frequent lane-changing and merging activities. This model could be used to evaluate the performance of expressway ramp design. © 2014 Elsevier Ltd.

Wang S.,Shanghai University | Wang S.,Old Dominion University | Qu X.,Griffith University | Yang Y.,Australian Institute of Psychology
Transportation Research Part A: Policy and Practice | Year: 2015

This paper proposes a novel method for estimating the perceived value of transit time of containers by shipping lines. The key idea is that a shipping line's published schedule is the optimal decision that minimizes the sum of fuel cost and time-associated costs of the containers adopted by the shipping line. Using the proposed method, we find that the adopted values of transit time for nine trans-Pacific services operated by Orient Overseas Container Line and five trans-Pacific services operated by Maersk Line are between US$5/TEU/day and US$30/TEU/day. We further demonstrate how the adopted value can be used for designing the optimal transit times between ports, analyzing the viability of slow-steaming, checking whether ships should speed up to catch up to connecting ships on other services, and helping to predict the market share of less polluting fuels in view of rules on air emission.

Kremer P.D.,Monash University | Symmons M.A.,Monash University | Symmons M.A.,Australian Institute of Psychology
International Wood Products Journal | Year: 2015

The present paper is the first to conceptually assess the viability of mass timber construction (MTC) as an alternative construction material/method in Australia. It fulfills an identified need to examine an innovative construction process providing much needed information concerning the technologies current position and future disruption to traditional construction methods. A common tool used in business management studies, the PESTEL model, Political, Economic, Social, Technological, Environmental and Legal is employed to provide structure for a strategic analysis of the technology. Mass timber construction clearly demonstrates some advantages including cost savings, primarily in the reduction in on-site labour costs; a lower environmental impact and use of a renewable resource; and possibility of improved amenity and reduced running costs for owners and occupiers. The estimated market potential for MTC in Australia indicates that a local plant might be viable as the market grows, and warrants funding to underpin a full feasibility assessment. © 2015 IWSc.

Weng J.,Shanghai Maritime University | Weng J.,Beijing Jiaotong University | Weng J.,Chongqing Jiaotong University | Xue S.,Beijing Jiaotong University | And 3 more authors.
Accident Analysis and Prevention | Year: 2015

This study investigates the drivers' merging behavior and the rear-end crash risk in work zone merging areas during the entire merging implementation period from the time of starting a merging maneuver to that of completing the maneuver. With the merging traffic data from a work zone site in Singapore, a mixed probit model is developed to describe the merging behavior, and two surrogate safety measures including the time to collision (TTC) and deceleration rate to avoid the crash (DRAC) are adopted to compute the rear-end crash risk between the merging vehicle and its neighboring vehicles. Results show that the merging vehicle has a bigger probability of completing a merging maneuver quickly under one of the following situations: (i) the merging vehicle moves relatively fast; (ii) the merging lead vehicle is a heavy vehicle; and (iii) there is a sizable gap in the adjacent through lane. Results indicate that the rear-end crash risk does not monotonically increase as the merging vehicle speed increases. The merging vehicle's rear-end crash risk is also affected by the vehicle type. There is a biggest increment of rear-end crash risk if the merging lead vehicle belongs to a heavy vehicle. Although the reduced remaining distance to work zone could urge the merging vehicle to complete a merging maneuver quickly, it might lead to an increased rear-end crash risk. Interestingly, it is found that the rear-end crash risk could be generally increased over the elapsed time after the merging maneuver being triggered. © 2015 Elsevier Ltd. All rights reserved.

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