Managing road safety
Collison data frequently asked questions
This page explains how we collect, check, publish and use information about road collisions and casualties in Swindon.
About the collision data
STATS19 is the national system used by the police to record reported road collisions.
The data only includes collisions that:
- happened on a public highway
- involved one or more vehicles
- resulted in a death or personal injury
- were reported to the police within 30 days
Collisions that were not reported to the police are not included.
Why we collect collision data
Around 354 personal injury road collisions happen on Swindon’s roads each year. These result in approximately 441 casualties.
Our Traffic Management and Road Safety team keeps a database of personal injury road collisions in the borough.
Wiltshire Police provides the information. We add it to our live database and check it before using or publishing it.
We hold more than 16,653 collision records dating back to 1990. We use mapping software with this data to identify:
- risks on the road network
- collision patterns
- clusters of collisions
- locations with high concentrations of collisions
This information helps us plan our annual road safety programme. It also helps us target spending where road improvements are needed.
How we check and publish the data
We collect road casualty data from Wiltshire Police. We then clean and check it using Department for Transport guidelines.
We usually publish one calendar year of collision data at a time. Published information is normally one year behind the current year.
This delay is because we must wait to receive the information from Wiltshire Police.
We investigate collisions as part of our legal road safety duties. These duties include considering and delivering appropriate road safety measures.
Our road casualty dashboards show where and when collisions happened. They also provide information about the people involved and possible causes.
How we use collision data
We use the data to identify collision clusters and locations where several collisions have happened.
The information also helps us:
- prioritise proposals that could improve road safety
- understand the nature and characteristics of collisions along particular routes
- prioritise spending on road improvements
- identify locations where lower speed limits could help
- develop evidence-based education programmes for different road users
These education programmes may be aimed at pedestrians, cyclists, motorcyclists, younger drivers and older drivers.
Why recent or expected collisions may not appear
Collision information for the current year may not yet be available. Wiltshire Police may not have provided the completed data to us.
A collision may also be missing because:
- it was not reported to or recorded by Wiltshire Police
- nobody was recorded as injured
- an injury was not reported to the police when they recorded the collision
- its mapped location is inaccurate
We make every reasonable effort to provide accurate information. However, we cannot guarantee that every record or mapped location is correct.
Collisions and casualties
A collision is the incident itself. It may involve any number of vehicles and people.
The published data only includes collisions in which at least one person was injured.
A casualty is a person injured in a collision. Casualty figures can be higher because one collision may injure more than one person.
Contributory factors
A contributory factor is something that the reporting police officer believes may have contributed to a collision.
These factors are subjective. They depend on the officer’s opinion, skill and experience when completing the report.
They are not necessarily based on an extensive investigation. Further enquiries may lead an officer to change their opinion.
More than one contributory factor can be recorded for a collision. Officers usually record two or three factors, but they can record up to six.
Injury severity
Killed or seriously injured
Killed or seriously injured is commonly shortened to KSI in road casualty data.
Slight injuries
Examples of slight injuries include:
- sprains that may not need medical treatment
- whiplash injuries
- bruising
- slight cuts
- slight shock requiring attention at the roadside
A person who is only shaken is not included unless they receive, or appear to need, medical treatment.
Serious injuries
Examples of serious injuries include:
- fractures
- internal injuries
- severe cuts
- crushing injuries
- burns, excluding friction burns
- concussion
- severe general shock requiring hospital treatment
- injuries requiring admission to hospital, either immediately or later
The serious category also includes people who die 30 or more days after a collision because of their injuries.
Fatal injuries
A fatal casualty is someone who dies within 30 days because of injuries sustained in a collision.
Confirmed suicides are not included.
Five-year averages
A five-year average compares figures across five complete calendar years.
The average for 2024 uses data from 2019 to 2023.