How crashes are recorded and analysed

Crashes have to be recorded by police to help determine who was at fault, and so that authorities can analyse causes and decide on solutions. Various forms are used to code the crashes. Every country has different methods, some involving coded diagrams and others, like in the UK, that are a lot of checkboxes and written descriptions. Members of the public can even get crash coding forms from police branches such as the Met.

But a real police coding form is a complex beast with a large number of sections to fill out, and it’s worth highlighting them so that you can see what factors police believe contribute to a crash.

As well as the number and type of vehicles and casualties, the speed limit and whether a police officer attended, the following are recorded:

Road type

Roundabout

One-way street

Dual carriageway

Single carriageway

Slip road

Unknown

Junction detail

Not at or within 20 metres of junction

Roundabout

Mini roundabout

T or staggered junction

Slip road

Crossroads

Junction more than four arms (not RAB)

Using private drive or entrance

Other junction

Junction control

Authorised person

Automatic traffic signal

Stop sign

Give way or uncontrolled

Pedestrian crossing – human control

None within 50 metres

Control by school crossing patrol

Control by other authorised person

Pedestrian crossing – physical facilities

No physical crossing facility within 50m

Zebra crossing

Pelican, puffin, toucan or similar non-junction pedestrian light crossing

Pedestrian phase at traffic signal junction

Footbridge or subway

Central refuge – no other controls

Weather

Fine without high winds

Raining without high winds

Snowing without high winds

Fine with high winds

Raining with high winds

Snowing with high winds

Fog or mist – if hazard

Other

Unknown

Road surface condition

Dry

Wet/damp

Snow

Frost/ice

Flood (surface water over 3cm deep)

Light conditions

Daylight

Darkness: street lights present and lit

Darkness: street lights present but unlit

Darkness: no street lighting

Darkness: street lighting unknown

Special conditions at site

None

Auto traffic signal out

Auto traffic signal partially defective

Permanent road signing or marking defective or obscured

Roadworks

Road surface defective

Oil or diesel

Mud

Carriageway hazards

None

Dislodged vehicle load in carriageway

Other object in carriageway

Involvement with previous accident

Pedestrian in carriageway – not injured

Any animal in carriageway (except ridden horse)

Type of vehicle

All vehicle types are listed, including motorised two- and four-wheel vehicles, ridden horses, mobility scooters, non-motorised vehicles (e.g. bicycles), agricultural and civil construction vehicles, trams and rail.

Towing and articulation

No tow or articulation

Articulated vehicle

Double or multiple trailer

Caravan

Single trailer

Other tow

Driver details

An estimate or accurate record of the age and sex of the driver of each vehicle and, if tested, their breath test results.

Hit and run

Not hit and run

Hit and run

Non-stop vehicle, not hit

Vehicle location at time of accident

On main carriageway not in restricted lane

Tram/light rail track

Bus lane

Busway (inc guided busway

Cycle lane (on main carriageway)

Cycleway or shared use footway (not part of main carriageway)

On lay-by/hard shoulder

Entering lay-by/hard shoulder

Leaving lay-by/hard shoulder

Footway (pavement)

Junction location of vehicle

Not at or within 20m of junction

Approaching junction or waiting/parked at junction approach

Cleared junction or waiting/parked at junction exit

Leaving roundabout

Entering roundabout

Leaving main road

Entering main road

Entering from slip road

Mid junction – on roundabout or on main road

Manoeuvres

Reversing

Parked

Waiting to go ahead but held up

Slowing or stopping

Moving off

U-turn

Turning left

Waiting to turn left

Turning right

Waiting to turn right

Changing lane to left

Changing lane to right

Overtaking moving vehicle on its offside

Overtaking stationary vehicle on its offside

Overtaking on nearside

Going ahead on left-hand bend

Going ahead on right-hand bend

Going head other

Skidding and overturning

No skidding, jack-knifing or overturning

Skidded

Skidded and overturned

Jack-knifed

Jack-knifed and overturned

Overturned

Hit object in carriageway

None

Previous accident

Roadworks

Parked vehicle

Bridge- roof

Bridge – side

Bollard / refuge

Open door of vehicle

Central island of roundabout

Kerb

Any animal (except ridden horse)

Other object

Vehicle leaving carriageway

Did not leave carriageway

Left carriageway nearside

Left carriageway nearside and rebounded

Left carriageway straight ahead at junction

Left carriageway offside onto central reservation

Left carriageway offisde onto central reservation and rebounded

Left carriageway offside and crossed central reservation

Left carriageway offside

Left carriageway offside and rebounded

First object hit off carriageway

None

Road sign/traffic signal

Lamp post

Telegraph pole/electricity pole

Tree

Bus stop/bus shelter

Central crash barrier

Nearside or offside crash barrier

Submerged in water (completely)

Entered ditch

Wall or fence

Other permanent object

First point of impact

Did not impact

Front

Back

Offside

Nearside

Journey purpose of driver/rider

Journey as part of work

Commuting to/from work

Taking school pupil to/from school

Pupil riding to/from school

Other

Not known

Casualty data

Casualty data is collected. The age, sex and severity of injury are recorded, and whether the casualty was a driver/rider, passenger or pedestrian. If they were a cyclist, was a helmet worn. If they were a passenger, was it in a bus or coach. Were seat belts worn. Finally, if they were pedestrians, where were they and what were they doing?