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Predicting traffic collision hot spots to improve road safety

Predicting traffic collision hot spots to improve road safety

The project developed new advanced methods to evaluate road safety schemes and predict collision 'hot spots'.

Project leader

Dr Neil Thorpe

Dates

2005-ongoing

Project staff

Dr Lee Fawcett

Joe Matthews

Keith Newman

Nicola Hewett

Sponsors

Engineering and Physical Sciences Research Council (EPSRC)

Northumbria Safer Roads Initiative (NSRI)

PTV Group

Partners

PTV Group

Northumbria Safer Roads Initiative

Description

It developed a suite of web-based tools for road safety practitioners. These tools integrate the new methodologies and algorithms developed.

The modelling approach has received international recognition as a leading, state-of-the-art application for collision hot spot prediction and scheme evaluation.

The range of use cases for these tools in the UK and internationally include:

  • scheme evaluation and future location of mobile road safety camera sites
  • hot spot prediction on motorways and trunk roads
  • development of road safety plans
  • spatial and seasonal effects on collisions
  • identification of road improvement locations

The retrospective scheme evaluation tool allows users to evaluate the effectiveness of existing road safety countermeasures. It does this by comparing collision/casualty totals before and after implementation.

It discerns a true treatment effect by removing any misleading statistical confounders from the data, such as regression-to-mean (RTM) and trend.

It uses a Bayesian algorithm and makes use of a Collision Prediction Model (APM) formed from data taken from a pool of reference sites.

As part of the output from the application, the user is currently able to see changes in casualty totals at their treated sites. It breaks down the output into change due to treatment, and change due to RTM and trend.

The tool presents the data as a summary table, and in the form of a bar plot. This information is available at both site specific, and network-wide levels.

The collision hot spot prediction tool makes use of an extended version of the statistical modelling approach. The retrospective scheme evaluation tool allows users to predict future collision counts at sites of interest using previous values.

There are a variety of outputs available. Plots detail the changing levels in road safety throughout the lifespan of the data. Additional summary tables also display this information.

There is also a "site warnings" page which allows the user to input their collision threshold and the probability of exceeding it. It returns a list of sites of concern to the user. This hot spot prediction functionality is also available as an add-in to PTV’s VISUM Safety program.