Part 9: Level crossings

Last updated: December 2008. This document ceases to be a controlled document when printed. Please refer to the current version at www.landtransport.govt.nz

3  Risk assessment/ALCAM

3.2  ALCAM description

ALCAM is an assessment tool designed to prioritise level crossing safety improvement works, as well as help determine the most effective safety improvements at these sites, in consideration of factors including cost. The model is a complex scoring algorithm that considers each site’s physical properties (characteristics and controls), including consideration of the related common human behaviours, to provide each level crossing with a ‘risk score’. This score is then multiplied by the site’s ‘exposure rating’ (a factor of vehicles, trains and consequence), which enables the comparison of the relative ‘total risk exposure score’ across level crossings within a given jurisdiction.

ALCAM produces an overall comparative risk score for each site, as well as highlighting where specific risks exist. It utilises ‘triggers’ or limits as a preliminary means of determining the potential level of risk (high/medium/low) at a site. ALCAM then allows for the determination of proposed treatments to address these risk areas, as well as consideration of the ‘cost versus risk reduction’ of these proposed treatments. A total data management system is provided (the Level Crossing Management System – LXM) to allow for the effective management of ALCAM data as well as other important information (such as accident history), which assists in the overall decision-making process.

The model allocates weighted points to existing characteristics at a level crossing to calculate a risk score for the site. The weightings applied have been determined through a series of workshops by an expert group, including representatives from each mainland state of Australia and covering expertise in road and rail engineering. In excess of 100 individuals, primarily from Australia’s road and rail jurisdictions, with expertise collectively covering the areas of level crossing safety have been involved in the development of ALCAM from its conception in 1999 through to its continuing development and use. The weightings take into account the likelihood and impact of a series of identified accident causal factors (accident mechanisms) and to what comparative degree each characteristic and control measure at a site contributes to and/or impacts on these accident mechanisms.

It is important to note that ALCAM is only one of the tools used in the safety assessment of level crossings. Consideration also needs to be made to address other elements, such as full social and economical impact, as well as site-specific safety factors. While ALCAM does produce various outputs, this does not preclude the need for sound engineering judgement. It should be used in conjunction with stakeholder site assessments, standards and other risk mitigation strategies. ALCAM should be applied by road and/or railway safety engineers or other similar, professionally qualified staff trained by approved ALCAM instructors in the proper application of ALCAM. This needs to be combined with appropriate expertise and experience in level crossing safety, risk management and knowledge of the applicable level crossing standards.

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