Collision data: frequently asked questions
Where does the data come from?
Devon and Cornwall Police supply Devon County Council with the collision (and resulting casualty) data.
Please note our database is not identical to the Police dataset mainly because we remove any collisions that are not recordable under the Department for Transport’s Stats19/20 data collection guidelines (for examples see Q9).
Why can’t I see any collision data for this year?
Collision data is released a calendar year at a time, around May the following year. This timeline is down to an extensive data checking process that helps to enhance the accuracy of the data. This process takes place once we have fully collected the data, checked for various errors and validated the records in line with data collection rules stipulated by the Department for Transport Stats19/20 guidance.
Finally before the data can be released we also liaise with the DfT directly to ensure our dataset is aligned and validated with what they have recorded for our area. Once fully aligned the data is officially “signed off” with the DfT which completes the process. This usually happens by the end of May every year.
I’ve looked for a collision on your map that I know occurred and cannot find it – why is it not there?
These are the most likely reasons (see question 9 for more details):
- The collision may not have been reported to/recorded by Devon & Cornwall Police.
- The collision may not have resulted in personal injury (or an injury was not logged with the Police at the time of recording).
- The collision may have been inaccurately plotted. Whilst every reasonable effort is made to ensure that the information provided is correct, no guarantees for the accuracy of the information are made.
Why are damage only collisions excluded?
We follow national guidance set out by the Department for Transport (DfT). They state that only “road accidents involving human death or personal injury occurring on the Highway” are to be reported.
What are the differences between a “serious” and “slight” injury/casualty?
The Department for Transport provide example of serious and slight casualties:
Examples of ‘Serious’ injury are:
- Internal injury
- Severe cuts
- Burns (excluding friction burns)
- Severe general shock requiring hospital treatment
- Detention in hospital as an in-patient, either immediately or later
- Injuries to casualties who die 30 or more days after the accident from injuries sustained in that accident.
Examples of ‘Slight’ injury are:
- Sprains, not necessarily requiring medical treatment
- Neck whiplash injury
- Slight cuts
- Slight shock requiring roadside attention. (Persons who are merely shaken and who have no other injury should not be included unless they receive or appear to need medical treatment).
What are the differences between collisions and casualties?
A collision refers to the incident itself. The incident can involve any number of vehicles and people. This data only includes collisions where a person / people were injured.
Casualties are the people themselves who are injured in the collisions. These numbers can be higher than collision numbers as a single collision can result in more than one casualty.
I’m sure someone was killed in a collision at a certain location, but it looks like it’s recorded as a ‘serious’ collision. Why would this be?
It might be because death occurred more than 30 days after the collision occurred. If this was the case then the Department for Transport state that the casualty severity should be described as ‘Serious’.
A collision I know about is showing up on the map in the wrong location
Please let us know via email@example.com. We are happy to query the collision location with the Police who initially plot the collision locations, and can correct our database independently.
In what exact circumstances would a collision not be recorded?
The DfT guidance document that relates to completion of road accident reports is called Stats20. Firstly it states that ” All road accidents involving human death or personal injury occurring on the Highway (‘road’ in Scotland) and notified to the police within 30 days of occurrence, and in which one or more vehicles are involved, are to be reported.”
Stats20 – Examples of accidents to be reported include:
- accidents which commence on the highway but which involve casualties off the highway (eg. where a vehicle runs out of control while on the highway and causes casualties elsewhere);
- accidents involving the boarding and alighting of buses or coaches and accidents in which passengers already aboard a bus/coach are injured, whether or not another vehicle or a pedestrian is involved;
- accidents to pedal cyclists or horse riders, where they injure themselves or a pedestrian;
- accidents resulting from deliberate acts of violence, but excluding casualties who are subsequently identified as confirmed suicides;
- accidents within bus stations/interchanges where they form part of the highway;
- accidents in Royal Parks (on roads to which the public have motor vehicle access)
Stats20 -Examples of accidents which should NOT be reported include:
- accidents which do not involve personal injury
- accidents on private roads (except Royal Parks) or in car parks
- accidents reported to the police 30 or more days after they occurred
- accidents involving confirmed suicides only.
Why do published collision numbers differ between the Police and the County Councils or Local Authorities?
Although Devon County Council follow the Department for Transports Stats19 and Stats20 guidance relating to which collisions should be included or excluded within collision databases, the Police will keep hold of additional records so their statistics are likely to be higher. The additional collision/casualty figures tend to come from these types of collisions that we do not have records of:
- collisions that involved confirmed suicide
- casualties where death was confirmed to be as a result of a medical episode rather than due to the collision itself
- collisions that occurred on private land e.g. caravan parks, garage forecourts
- collisions that occurred within a car park
Also please note that the Police tend to report statistics on a financial year basis (April to March) where as we tend to release statistics based on calendar years (January to December).
Where can I find more information on what the Police have recorded?
You can contact the Police direct for collision related information, for more details please see their website.
Where can I see collisions recorded outside of the Devon County Council area?
Here is a national collision map available via www.collisionmap.uk
I have seen a collision on your map that isn’t showing on the national map
It’s most likely because it was previously incorrectly plotted and we have since corrected the location, but the national map has not been subsequently updated because they are fed by national DfT data which is locked down once they have signed off with every local authority each year. (For more info on this signing off procedure see Q2).
Where can I find more details on national statistics?
The Department for Transport (DfT) publish an annual report called ‘Reported road casualties Great Britain’ which is a very detailed document with data tables relating to collisions and resulting casualties.
The report is released every Autumn, the latest reports can be found here.
Collision data source
The collision data that we use is called Stats19 data; the collection and recording process is governed by the Department for Transport (DfT). In summary the DfT stipulate that Stats19 collision data should only consist of collisions that:
- were recorded by the police
- occurred on a public highway
- involved human death or personal injury
- involved one or more vehicles
- were notified to the police within 30 days of occurrence.
Accuracy checks and release of data
We conduct our own accuracy and validation checks on this data after we have received it from the police. The data has to be checked and fully validated by the DfT before it can be released – this validation process with the DfT is undertaken annually every spring and is usually complete by the end of May at which point we can then release the data for general use.
While every reasonable effort is made to ensure that the information provided is correct no guarantees for the accuracy of information are made.
Plymouth and Torbay
Plymouth and Torbay collisions are not collected by Devon County Council as they form their own unitary council areas and collect their data separately.
- Plymouth City Council – Road safety
- Torbay Council – Road safety
- View Torbay and Plymouth collisions on a national collision map
If your query has not been answered here please send it to the Safer Travel Officer at firstname.lastname@example.org