Kathirgamalingam Somasundaraswaran

Review of crash prediction models and their applicability in black spot identification to improve road safety

Objective: This study aims to review of the development of crash prediction models, and their applications to analyse and identify black spots to improve road safety. Methods: Several modelling techniques have been reviewed in this study including, multiple linear regression, Poisson distribution, negative binomial, random effect technique, and multiple logistic regression models to identify their suitability to develop the crash prediction models. The studies related to the identification of black spots were also reviewed based on the type of crash data used in the identification process. Result: The reviewed documents highlight the shortcomings within the traditional crash prediction models (CPMs), as well as the demonstrated the flexibilities and effectiveness of the latest methods. Most suitable models can now be developed to represent the actual scenarios from several modelling techniques, where they provide a realistic and accurate prediction of crash frequency, for example, to determine if the location had a traffic safety problem compared to other locations with similar conditions and to identify the suitable measures to reduce crashes. Application/Improvements: The models identified in this research are already being used but the modelling approaches can be further modified to include the latest technical application on roads, available post-crash management system or safety culture which are commonly related road safety outcomes.

REHABILITATION WORKS IN QUEENSLAND USING FOAMED BITUMINOUS STABILISATION

Adapting foamed bitumen stabilisation is considered as the most cost effective approach in Queensland to expedite the rehabilitation works, especially after the major flood devastation in 2011. This paper presents the key changes made as well as the recent practices adapted during a road rehabilitation work to increase the return from the investment. In this process, initially, the designed width for subgrade lime stabilisation has been modified to minimize the moisture entry into the pavement. The dry modulus, three days soaked resilient modulus and retain modulus were used to identify the suitable base material for construction. In addition, a trail site was used to examine the bulking effect on base layer when adding lime as secondary agent, which helped to estimate the exact depth for foamed stabilisation. A few innovative techniques such as a two-layer compaction to effectively condense stabilised subgrade, was used to improve the quality of the outcome were also highlighted.

Impact of the Application of International Quality Processes on Engineering Education at Universities in Sri Lanka

Globally, the delivery of engineering degree programs and accreditation processes for benchmarking the quality of engineering education have been improved with introduction of the Washington Accord. This paper highlights the overview of engineering education conducted by the national universities in Sri Lanka, and the impacts of the application of international quality processes on their delivery. Currently three national universities offer highly competitive engineering education in Sri Lanka; the University of Peradeniya, the University of Moratuwa and the University of Ruhuna. The University Grants Commission (UGC) and the Institution of Engineers, Sri Lanka (IESL) have been working together with these universities to assure the relevance and the quality of engineering education. After the Washington Accord, the several notable actions have been employed to ensure quality engineering education, including: institutional and subject reviews carried out between 2005 and 2009 by UGC; the introduction of an improved accreditation process in 2006, and initiatives towards international recognition by IESL in 2007. As a result IESL currently holds provisional status in the Washington Accord and has become a member of the Engineering Mobility Forum.

THE EFFECTIVENESS OF USING VARIABLE SPEED LIMIT ON THE PERFORMANCE OF AN INTERRUPTED FLOW

The urban traffic congestion is getting worse with ever increasing urban population and vehicle ownership. The long queues at intersections and blockage of traffic on urban arterial roads become routine during the peak hours. Interrupted traffic flow through signalised intersections and arterial roads have badly been affected by these occurrences. Thus this paper examines the possibility of employing variable speed limit (VSL) for upstream traffic during the peak period to improve the traffic performance through signalised intersections as well as in urban arterials. The micro simulation software VISSIM was used to examine a hypothetical road network under VSL application. An expected traffic flow near capacity condition was simulated several times to see the effectiveness. Results show that for a reasonable period of time, the VSL application to the upstream traffic improve the traffic performance at immediate downstream intersections in terms of vehicle delay (16%), average queue length (18%) and average number of stops per vehicles (16%), while intersections located far from the VSL application has no or little effect. Similarly, the arterial performances have also been improved for a short period of time on the immediate downstream link in terms of density (13%), space mean speed (10%) and traffic flow (2%), the effective is negligible on the links located far. In addition a slight improvement was noticed to the total journey time on the immediate link