SUMMARYThis paper presents a critical investigation of reasons for using transit by residents of the City of Calgary, Canada. Reasons for using transit are expressed as functions of people's perceptions and attitudes towards transit service quality and attributes. A multinomial logit model combined with latent variable models is developed to capture unobserved latent variables in defining perceptions and attitudes. Using data from a transit customer satisfaction survey conducted in 2007 by Calgary Transit, this approach models the reasons for choosing transit and tests the significance of two individual specific latent variables: perceptions of 'reliability and convenience' and 'ride comfort'. Many behavioural details are revealed that have important policy implications. Most importantly, it is found that the people of Calgary value 'reliability and convenience' over 'ride comfort'. As for policy implications of the findings, it is clear that improving the connectivity of train service, reducing multimodal transfers, and increasing dedicated right-of-ways for transit would effectively increase transit ridership in Calgary. Copyright Understanding the public's attitudes, perceptions and knowledge in relation to transport measures is important for the formulation and monitoring of transportation policies. Demand for an efficient transit system in any urban area stems from mobility, environmental and energy objectives. Measurements of a transit system's service quality is a challenging research theme and of great importance to the transit service providers and regulatory agencies [1]. The actual performance of a transit system should be considered from the transit users' perspective [2]; and, although there has been demand for analysing transit service quality based on how the users perceive it [3], very few studies truly concentrate on attitudes or psychological factors behind the users' perceptions of transit service quality. Attitude towards transit is an important element influencing people to choose transit in our autooriented North American cities. Attitude, often expressed as perception, is an abstract and psychological term and plays the major role in governing behaviour and defining action [4]. Actions towards transit usage can be traced back to the users' perceptions of the service quality of a transit system. In order to influence peoples' actions in terms of transit over automobile usage, it is germane that we understand the factors influencing formation of attitudes or perceptions towards transit, because people's attitudes are reflected in their travel related actions [5]. This paper follows this principle of investigation in order to identify the factors influencing transit modal share. However, other than focusing on a conventional mode choice model of transit modal share, we have taken a different approach. JOURNAL OF ADVANCED TRANSPORTATION

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With the recent advances in active transportation and demand management, variable speed limits (VSLs) have been identified as an active traffic management strategy for improving freeway mobility and safety. Several heuristic VSL strategies have been proposed and evaluated. This paper proposes a model predictive VSL control strategy and evaluates its safety and mobility impacts. The strategy uses second-order traffic flow models to predict the traffic state and to provide a speed for optimizing corridor operational performance. A sensitivity analysis of the VSL update frequency and the safety constraints for the VSL strategy was performed to determine the best scenario in terms of safety and mobility. A stretch of Whitemud Drive, an urban freeway corridor in Edmonton, Alberta, Canada, was selected as the study area. The proposed VSL strategy was implemented in the microsimulation platform with a special software module. A real-time collision prediction model was developed for the same study area by using a matched case-control logistic regression technique to estimate the collision probability for each scenario. The results indicated that the proposed VSL control strategy can improve safety by approximately 50% and mobility by approximately 30%. A VSL update frequency of 5 min and a maximum speed difference of 10 km/h between successive time steps yielded the best performances. This finding can be useful for field implementation of VSL control.

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