The Crash Detectives

In this episode, could CCTV reveal the truth behind a fatal motorbike crash? And after a three-car crash in heavy rain, the team are left stunned by what they discover.

A four-car crash and a multi-emergency response - the team must act quickly to piece it together. And after a single-vehicle crash on the M4 on Christmas Day, they are suspicious that there is more to it than meets the eye, and turn to science to get to the truth.

When a tractor crashes into a family car on a busy city street, officers search for the truth behind the lies and get more than they bargained for when they reconstruct the events of the night.

In the final episode of the series following the work of Gwent Police's Collision Investigation Unit, the team are alerted to a serious crash by the latest in-car technology, and turn to 3D laser scanning to help establish the facts of what happened. And after a van crashes into a bus shelter, they must find and interpret the evidence to solve the mystery of why the driver lost control.

The Crash Detectives are called in to investigate a hit-and-run that leaves a cyclist fighting for her life, while mystery surrounds the death of a delivery driver on a busy dual carriageway.

When calls start coming in to report debris on the M4 motorway, police discover that a father and son have been in a serious crash. As traffic chaos builds, the pressure's on for the collision team to find out why the car left the road.

When a Friday evening trip out in the car ends in a fatal crash, the driver refuses to accept his driving is to blame. The collision team must find the evidence to prove the real story of the night.

When a head-on crash leaves a grandfather dead, Chris discovers the answers could lie in electronic data within the car. As his mission to access it begins, he unearths an intriguing story of what really led up to the crash.

The collision team are called in to investigate a high-speed crash on the M4 which closes the motorway in both directions. With a driver under arrest and offering few clues, the answers could lie with a silent witness.

A pedestrian is seriously injured after being struck by a car in a residential street, but police are suspicious of the teenaged driver's version of events. After a motorcycle crash outside a busy garden centre, the full story is revealed - by the bike itself.

It's Friday night, and desperate 999 calls start flooding in to report a car travelling the wrong way along the motorway - but it still ends in tragedy. A motorbike and van collide in a busy city centre, but the story isn't as clear as it first seems.

When a woman dies after being hit by a lorry on her way to play bingo, the team must reconstruct the scene of the crash to find out who's to blame. A cyclist fights for his life after a crash with an articulated lorry.

When a man is found dead on a dark mountain road, there's no sign of a vehicle. With just fragments of debris for clues, the pressure is on to track down the driver that's fled the scene.

An 18-year-old man has died in a head-on crash on a country road. As word of the tragedy begins to circulate on social media, a horrifying tale of recklessness is about to be exposed.

A motorcyclist dies in a crash at a busy city junction.

A road worker is hit by a modified car during a police pursuit. However, when the driver fails to stop, the race is on to track the car down and bring the offender to justice.

A 52-year-old cyclist has died after being knocked off her bike by a white van as she raced on a dual carriageway near Raglan in Monmouthshire. She was just nine minutes into a time trial with a group of other competitors when her ride was cut tragically short. With the van driver now under arrest and facing serious questions, Sergeant Cath Raine has been called in to investigate the final moments of the cyclist's journey. But the collision has happened on a concrete road, with barely a trace of evidence on its surface – and she knows that even a single mark could hold the key to justice. So when she finally discovers a clue at the edge of the carriageway, it raises more questions than answers.

The collision team investigate a late-night crash on an unlit dual carriageway. They are stunned to discover the seriously injured man was travelling on an electric scooter.

PC Richie Wyatt is on a residential street in Risca, Caerphilly, after a powerful sports motorcycle collides with a brick wall. Two men were travelling on the bike at the time, and they have both been seriously injured. Close examination of the damage to the bike reveals the dynamics of the collision, but it's not proving straightforward to establish why the rider lost control.In Chepstow, air ambulance doctors are treating a seriously injured woman after the car she was travelling in collided with a stationary lorry. She has been cut free from the wreckage, but as Sergeant Bob Witherall arrives at the scene, the damage quickly reveals the true extent of the impact.

A huge emergency response is underway on an industrial estate in Croespenmaen in Caerphilly. Two lorries have collided – and while one driver has managed to escape unhurt, the other driver is now seriously injured and trapped in his cab. As desperate efforts to free him get underway, critical care doctors arrive by helicopter, and Dean Burnett and Sergeant Rhys Dickinson are called in to search for answers.With the amount of activity going on at this volatile scene, they're in no doubt that they could lose vital evidence and must begin a race against time to establish how the two trucks crashed. But as the evidence is unpicked, one driver's story starts to unravel.

Sergeant Cath Raine is on duty when a woman riding an electric scooter is seriously injured in a crash on her way to work in Newport. She's been struck by a car, and with the driver under arrest, all eyes are on Cath to work out what's happened. But when it emerges that the collision has been captured on camera, she's making no assumptions and insists that all viewpoints are considered.When a crash triggers an automated call from a tourist's motorbike, paramedics and police are quickly alerted to their location in Raglan, Monmouthshire. As the seriously injured rider and pillion passenger are on their way to hospital, PC Richie Wyatt arrives at the scene. But the challenges posed by the tight bend of this slip road mean he's no stranger to investigating here, and the pressure's on to find new evidence relating to this latest collision.

Traffic is at a standstill after an early-morning crash on a busy dual carriageway, near Usk in Monmouthshire, A man driving a Vauxhall Astra has died after his car collided with the rear of a lorry, and Pc Richie Wyatt has been called in to investigate. This scene is littered with debris, and despite a painstaking process to work through it, there are few clues to explain this fatal loss of control.It's now key to check out the lorry driver's version of events – and focus turns to vehicle tracking data to reveal the true picture of its movements in the lead-up to the collision. But when officers seize dashcam footage captured from the opposite side of the carriageway, it only adds to the mystery of why the driver lost his life.

The race is on to track down a driver who has fled the scene of a serious crash in Newport, leaving his friend critically injured on the road. The victim has been thrown from the back seat of a Volkswagen Polo – and as medics treat him and a seriously injured woman, a manhunt is gaining pace. But for Sergeant Cath Raine and PC Matt Rue, working out how the car collided with a Citroen C3 is proving to be a tough challenge.With few clues and mounting pressure, they can only hope that the road surface finally decides to give up its clues. With the suspected driver still on the run, the car's onboard data could be about to expose the chilling truth about his actions behind the wheel. But as inquiries take a forensic turn, it transpires that this isn't the only crime he needs to explain.