Malaysia adopted haddon matrix to conceptualize its strategies in our previous road safety plan and also for the establishment of Malaysia Institute of Road Safety Research (MIROS)
As mentioned by Mr. Jiri above, it's a concept thing
The US National Institute for Occupational Safety and Health has a Fatality Assessment and Circumstances Evaluation program that uses the Haddon Matrix as a tool for qualitative epidemiology for investigating the risk factors regarding fatalities. You may want to check out its website.
In line with Mr Zulhaidi Mohd Jawi, I attach here a simple application of Haddon Planning Matrix and hopefully it would assists you to have clear understanding.
For you kind information....it is an approach for the understanding its conceptual framework not a method for identifying the cause of road accident occurrence .If you are interested for detailed consequences then use what if analysis method...it is systematic but full qualitative.