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SAI-RTC is the Self Administered Interview for Road Traffic Incidents

Critical evidence in road collision cases often comes from eyewitnesses, yet frontline officers often have limited resources for interviewing and taking detailed statements from witnesses.

The aftermath of an RTC is often busy, and frontline roads policing officers have to contend with many competing demands. Vital information can be lost in the period between the incident and a subsequent follow-up contact from police.

The SAI-RTC draws heavily upon the original SAI, following a similar structure and incorporating similar retrieval support. However, the SAI-RTC incorporates new sections and instructions designed specifically for the roads policing context. There are specific prompts and cues relating to vehicles, drivers, and road conditions (including traffic, visibility, and weather).

Witnesses who completed the SAI-RTC provided significantly more information than witnesses who completed the standard reporting form.

Witnesses using the SAI-RTC reported a 57% increase in overall details compared to a standard reporting form

Key research findings

Between 2019 and 2021, the Road Safety Trust funded a field trial of the SAI-RTC, which was conducted in partnership with the Roads Policing Unit within South Wales Police. This trial compared witness reports obtained via the SAI-RTC with reports obtained via a free recall form, which standard operating procedure within the Roads Policing Unit.

Witnesses who provided their account via an SAI-RTC provided more detail than witnesses who completed the standard form. This was true overall (57% increase), and for each category of detail analysed (e.g., person details, vehicle details, spatial details). Witnesses who completed the SAI-RTC were also much more likely to report whether they had discussed the collision with anyone else, the road and weather conditions at the time of the collision, and whether they had corrected or normal vision.

Ongoing work

The Road Safety Trust have funded the development of an online version of the SAI-RTC. Work is currently underway to develop, implement, and evaluate this tool within South Wales Police.

Road Layout


Increase in detail

People involved


Increase in detail

Vehicles involved


Increase in detail

WHAT PEOple did


Increase in detail

when things happened


Increase in detail

where people/vehicles were


Increase in detail

Officer Feedback


of surveyed officers found the SAI-RTC produced reports that were as detailed or more detailed than the standard reporting form


of officers considered the SAI-RTC to be as useful or more useful than the standard reporting for

Witness Feedback


of witnesses reported that the SAI-RTC was either very easy or quite easy to complete


of witnesses reported that the SAI-RTC definitely or probably helped them remember the incident in more detail


The Self-Administered Interview (SAI) is an investigative tool that can be used to elicit comprehensive initial statements from witnesses, quickly and efficiently. It takes the form of a standardised protocol of clear instructions and questions that enable witnesses to provide their own statement.

The Self-Administered Interview can be distributed quickly in circumstances where resources are limited and where it may take time for face-to-face interviews to take place. Such delays increase the likelihood of memory decay and distortion.

Prior research has shown that witness accounts obtained via the SAI result in more detailed accounts than other reporting formats, and that completing the SAI soon after an event protects the memory of that event from forgetting and manipulation over time, leading to more detailed subsequent accounts.

The most recent field trial focussed on testing the effectiveness of a revised SAI tailored to the roads policing context, the Self-Administered Interview for Road Traffic Collisions (SAI-RTC).

The roads policing context is ideal for the use of the SAI, as witness accounts are often pivotal to the successful investigation of road traffic collisions (RTCs) investigations, yet frontline roads policing officers often lack the resources to take comprehensive accounts from witnesses. This is especially true when there are multiple witnesses at the scene.

Dr Ruth Horry

Swansea University
Singleton Park, Sketty
Swansea, SA2 8PP
T: +44 (0) 1792 295927