Time-Position-Visibility Analysis: A Graphical Approach

Reconstruction of vehicular accidents frequently involves developing an understanding of time-position relationships -- “who was where when”, position-visibility relationships -- “who could see what from where”, and time-position-visibility relationships -- “who could see what from where when”. A spreadsheet calculation is used to generate the pre-impact time-position history for vehicles traveling along known paths at known or estimated speeds. The position-visibility relationship is determined either by direct measurements at the site, or by measurements from a scale site diagram, or both. A spreadsheet/graphical analysis combines the position-visibility and time-position results into a time-position-visibility presentation format which is used both for analysis and for presentation of results. This technique is particularly well suited to performing sensitivity analyses to explore the effects of uncertainties in vehicle speeds and approach paths.