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Accident reporting methodology

Note on methodology

Statistical information on national road crashes causing injuries (number of fatalities within 30 days or injured) are gathered by the Italian National Institute for Statistics (ISTAT). The Automobile Club d’Italia (ACI) also cooperates in the survey in compliance with a specific Memorandum of Understanding.

The survey is jointly carried out by ISTAT, ACI, Ministry of Interior (Road Police), Carabinieri, Provincial Police, local Police, Statistical Bureaus of Provincial head towns, as well as of some Provinces or Regions. The afore said institutions have signed an agreement with ISTAT to gather, check, capture and finally send the relevant data to ISTAT in a commonly agreed format.

Road accidents causing injuries are reported by the authority attending an accident scene (Road Police, Carabinieri, local or Provincial Police etc.) by either sending the data through a file or filling in the so called ISTAT CTT/INC paper form.

Collected information concern number and type of road users involved (drivers, passengers, pedestrians), outcomes, location and circumstances of the road accident. In particular, collected data provide details on place (in or outside urban areas) and time of the car crash, name of the reporting authority, type of vehicles involved, events giving origin to the accident, effects on people involved.

Coverage, unit of analysis and main definitions 

The survey covers all road accidents which occurred on public roads during a calendar year - as reported by any competent authority – and caused casualties (fatalities within 30 days or injured). According to international regulations - issued by Eurostat, OECD, UNECE, etc.- and adopted also in Italy, road accidents are defined as “those events causing injuries involving at least one vehicle”. 

Therefore, coverage includes all road accidents which occurred on public roads, involving both stationary or moving vehicles and causing injuries. Road accidents not causing injuries, or not involving vehicles, as well as those which did not occur on public roads are not covered. The unit of analysis is the individual road accident with injuries.

The most important definitions employed in the survey are indicated below:

• road accidents: are those occurring on a public road, involving at least one vehicle and causing victims (injured or killed).

• fatalities: people immediately killed (within 24 hours) or those who die between the second and the thirtieth day from the day of the accident included.

• injured: people having suffered any kind of injury – regardless of their gravity - as a consequence of a road accident. No uniform definition for “seriously injured” has been adopted by all EU countries so far; the European Commission has proposed to use the current scale, called “Maximum Abbreviated Injury Scale” (MAIS). The seriously injured is ranked with MAIS3+.

Main reported items

• Date, time, and place of the accident 

• Reporting authority

• Location of the accident: within or outside built-up areas

• Type of roads 

• Paving of roads

• Road surface conditions

• Road signs

• Weather conditions

• Type of accident (crash, run-off-road collision, run over, etc.)

• Type of vehicles involved

• Circumstances of the accident

• Aftermath of road accidents on people involved

• Names of: dead and injured people as well as of the hospital where they have been taken to


The respondents to the survey are the Italian Police authority (Polizia Stradale1, Carabinieri, or Local Police) and other relevant bodies.

Respondents can be classified according to their data collection model, which can be either decentralized - with an intermediate data processing stage by a peripheral unit - or standard.

A IT decentralized model has been adopted on a national basis for data coming from the Polizia Stradale and Carabinieri: consequently, all road traffic accidents involving personal injuries in Italy are transferred from the Polizia Stradale or the Carabinieri to Istat, on a monthly or quarterly basis.

Both a decentralized and a standard model have been used for data coming from the Local Police depending on the province or region concerned.

An IT decentralized model is used in the following regions: Piemonte, Lombardia, Friuli Venezia Giulia, Veneto, Emilia Romagna, Liguria, Toscana, Puglia and in the autonomous provinces of Bolzano and Trento. The above said regions and autonomous provinces manage the various stages of the survey and transfer to Istat the data which were collected by the Local Police. Likewise, Istat branches manage the survey in the regions Marche, Umbria, Molise, Campania and Basilicata.

An IT decentralized model is provided on a province basis too, such as in the province of Crotone.

Finally, an electronic or paper standard model is provided in Valle d’Aosta, Lazio, Abruzzo, Calabria (except the province of Crotone), Sicilia and Sardegna: the local Police send electronic data or mail paper data to Istat, who manages all stages of the survey.

Data Processing

Data are checked and adjusted through a number of steps, starting from a preliminary assessment of the information consistency in each “accident record”. Following steps include the application of deterministic and probabilistic assessment methods in order to correct errors.

All the recurrent steps of the correction procedure can be summarized as follows:

• redoubled data-entries deletion and out of coverage data deletion;

• correction of out-of-range data;

• correction of systematic or logical errors thanks to the generalized software Con.Cor.D. (Data Control and Correction);

• check and amendment of road accidents location

Variables contributing to accurate road accident location are submitted to ACI for a thorough check and for providing correct location in case of incomplete or missing data.

For more details, please visit ISTAT website