Essex Police has given an insight into how it deals with serious crashes across the county.

The police’s Serious Collision Investigation Unit (SCIU) have already investigated almost 30 serious and fatal collisions in Essex so far this year.

From the time a 999 call is made, detectives are in a race to secure evidence at the scene of a collision whether it is declared as a serious collision involving traumatic injuries that are life-changing such as loss of limbs, paralysis, burns, brain injuries or loss of sight, or declared as fatal.

Until officers are on scene, there is a risk of evidence being lost, destroyed or contaminated.

SCIU officers fulfil several roles when they respond to crashes such as vehicle examiner, family liaison, evidence gatherer and vehicle removals.

Their initial actions at a collision are in keeping with the pneumonic CHALETS.

C asualties – Their first responsibility is to preserve life, make the scene safe to prevent further injury or further accidents and to render first aid.

H azards – They make sure that the scene is safe for the emergency services to work at; hazards present may mean fuel or chemical spillage, fires, gas leaks, debris and even bad weather.

A ccess – What are the best routes for emergency services to use? Are routes blocked? Can other road users gain access to the collision scene and therefore destroy potential evidence?

L ocation of incident – What is the exact location? Is it a problematic location making investigation difficult?

E mergency services – Are they all present, or required?

T ype of incident – How many vehicles are involved? How many are injured?

S afety – The safety of all those involved is paramount and a dynamic risk assessment must take place to ensure everyone’s welfare.

The work at crash scenes is carried out by SCIU and Roads Policing operational teams based at Stanway and Chigwell.

“The amount of evidence gathering at a scene cannot be underestimated,” Insp Mark Fraser went on to say.

“We only have one chance to get it right.

“It would be terrible if we went to court only to find we missed taking a photograph of a car in situ or forgot to measure the marks on the road to show how fast a car or lorry was travelling at the time; it just wouldn’t be good enough for the people involved, and I know my detectives would be devastated if a case was dismissed because we rushed to reopen a road.

“That’s why we thank the public; for being supportive and leaving us to get on and investigate.”

SCIU officers investigate and log every detail such as; who is present when they arrive and who else comes to help; they make a note of where there is debris, blood or what position a vehicle comes to rest.

They aim to secure the crime scene by cordoning off with tape and prevent unnecessary personnel from entering.

The most valuable “piece of evidence” to an investigating officer is a person - someone involved in the collision or someone who witnessed it - and their account in the first stages of the investigation helps SCIU determine what has happened.

But police say some witnesses are in a state of shock and need to be treated slowly and sympathetically so that they accurately recall what happened.

SCIU officers are required by law to breathalyse drivers and riders to see if their ability has been impaired through drugs or drink and they will check the road-worthiness of a vehicle – brakes, dirty windows or rusting parts - to see if that too is a contributing factor to a collision.

But once the road is reopened, the work of SCIU doesn’t stop there.

Increasing numbers of vehicles are fitted with dash cams capturing the moments before a collision, helping officers establish any contributary factors.

Hours of CCTV footage can place a vehicle at a location at a given time and phone records can prove whether the driver was using a mobile, distracting them and breaking their concentration. It’s also a priority in any investigation to trace a vehicle that fails to stop at the scene of an accident.

“During a collision investigation, the hours can be long and the attention to detail required is high.

“Dealing with the emotional distress triggered by the nature of a fatal collision is just as traumatic for officers as it is for those involved.

“We must look after each other and support one another.

“But where a collision is preventable, then that’s what we all must do – prevent it from happening.”