Month: September 2013

On Tuesday 24th September 2013, at Bruntingthorpe Proving Ground, Mike broke the current blind land speed record by driving an average speed of 186mph.

Datron Technology were in charge of timing the event.

The results were transmitted to a laptop via radio modem from the car, which meant the team knew instantly that the record had been broken. 

Rod Shephard is the principal investigator with Accident Investigation Training Services (AiTS) and is a former police officer with the Devon and Cornwall Accident and Collisions Investigations Unit. When Rod retired from the force he was offered the job at AiTS because of his wealth of experience and expertise in crash scene investigation. Rod is currently studying for his PhD in the field of motorcycle dynamics, aided by the expertise and dedication of Mark Hargreaves and the staff at Datron Technologies. He’s an expert in the use and interpretation of accelerometer data and uses this knowledge and understanding to teach police officers throughout the country how to use the VERICOM VC4000 and more importantly how to effectively interpret the data it supplies. Rod spoke to Datron recently and outlined his thoughts about the VERICOM VC4000 and how it had transformed the field of collision investigation.

The VERICOM VC4000 is the latest range of GPS-enabled instruments to be adopted by the Police to aid its collision investigations. These instruments are used for measuring and recording deceleration, co-efficient-of-friction and Skid-to-Stop testing. A total of 18 of the Police Forces in England, Wales and Ireland now use these instruments and more will no doubt follow. VERICOM instruments offer several advantages over more traditional skid testers and decelerometers that have previously been used by Police Collision Investigators (PCIs). Because VERICOM instruments have Dual and Tri-axis accelerometers built-in, they are able to measure not just the vehicle Skid-to Stop and Road Friction co-efficient, but also vehicle accelerations to set speeds, between set speeds and also over-time and over-distances which are set by the user. The feature-rich VERICOM incorporates many additional functions like forward and lateral acceleration measurement, instant viewing of the test results and a large data memory.

How has the VERICOM VC4000 changed accident investigation?
“The VERICOM VC4000 system is an accelerometer which can do many things. It can work out how quickly a car brakes: in other words it will allow you to work out what’s called a co-efficient of friction on the road surface. Essentially what it does is work out a gravity force-type value, and from that you work out how much braking and friction there is on the road. With this information you can then calculate how quickly a car should be able to stop.”

“It will do acceleration tests. It’s a similar sort of function that ultimately works out a G value. It’s all about force. What you’re trying to do is work out how quickly a car can accelerate. So imagine you’ve got a car in a side road, waiting to pull out into a major road: we can work out the feasibility of how quickly that car could pull out of the junction on to the major road. From that we can therefore determine whether the car travelling on the main road would have hit it or not. What it means essentially is that in any incident of this type the accelerometer enables you to work out the speeds of the vehicles involved and determine whether the manoeuvres undertaken were safe or not.”

So has this ‘new’ technology made your job easier?
“It’s not new technology: the VERICOM system is a new piece of ‘equipment’, but using existing technology. What makes it different is that it presents the information in a way that’s more useful and usable to people like me and other non-scientists. It was developed by VERICOM computers in the States for collision investigation using technology that been around for centuries – ie gravity. There already was another piece of equipment, developed in Yorkshire, called Skidman which did the same sort of thing: the problem was it wasn’t easy to use, and interpreting data was complex. VERICOM has developed this piece of equipment which gave you all the information you’d ever need, but made it user-friendly. What’s more they’ve managed to put in accelerometers in all 3 axes: the X axis, longitudinal to the vehicle, the Y axis, sideways to the vehicle and the Z axis, vertical to the vehicle. So what we’ve now got is a three-dimensional accelerometer.”

“What this means is that we can use it in lots of different ways and scenarios. It’s no longer just for use on a car, but can be used on motorcycles, lorries, coaches and all different types of transport. Here’s an example for you: Grannie is sat on the front seat of a bus travelling from home to the shops. The driver brakes suddenly and Grannie slides off the seat and is injured. When we investigate the incident, we’d need to know whether the braking force applied was excessive. By putting the accelerometer onto the bus, we can work out where she was before the driver applied the brake, and determine whether the driver’s use of the brake was reasonable in the circumstances or too heavy footed. The VERICOM VC4000 system opens up the arena of collision testing and gives us access to a multitude of applications that were only previously available through scientific procedures.”

What do police officers learn about the VERICOM VC4000?
“This piece of kit is very good, in that it allows police officers with a minimum of training to capture data which would at one time have been almost impossible to capture without a mass of equipment and technical knowledge of some specialised procedures. All the information they need is there on screen. However, it’s the interpretation of this data that takes a little more knowledge and experience. Police officers need to be able to understand what the information is telling them. It’s easy for scientists because they can come along with all their equipment and analyse the data without a problem; but for anyone who isn’t a specialist, it’s more complicated and involved. What the VERICOM does is capture a huge amount of data more simplistically and easily and give out basic readings. The interpretation of the data is where AITS and other training organisations come into the equation. We teach the police officers what this data is, what it means and how to interpret it.”

The VERICOM VC3000 and VC4000 are the latest range of GPS-enabled instruments to be adopted by the Police to aid its collision investigations. These instruments are used for measuring and recording deceleration, co-efficient-of-friction and Skid-to-Stop testing. A total of 18 of the Police Forces in England, Wales and Ireland now use these instruments and more will no doubt follow.

The VERICOM instruments offer several advantages over more traditional skid testers and decelerometers that have previously been used by Police Collision Investigators (PCIs). Because VERICOM instruments have Dual and Tri-axis accelerometers built-in, they are able to measure not just the vehicle Skid-to Stop and Road Friction co-efficient, but also vehicle accelerations to set speeds, between set speeds and also over-time and over-distances which are set by the user. The feature-rich VERICOM incorporates many additional functions like forward and lateral acceleration measurement, instant viewing of the test results and a large data memory.

A unique feature of the VERICOM is its Run Duration Protocol (RDP) function. Many deceleration testers measure the deceleration from a typical minus 0.2G falling trigger point, through to a rising minus 0.2G stop point. Unfortunately this will not give wholly accurate test results as the measurement should stop when the vehicle speed is zero, not the minus 0.2G rising point. This can leave a considerable room for error in the calculation of deceleration, speed and distance, because the data used was inaccurate. By using the VERICOM with its RDP function, Police Collision Investigators can be confident that their test data is completely accurate, which is vitally important, should the case proceed to court.

Datron was lucky to catch up with one of those Police Officers recently, Sergeant Tim Alderson. Tim works for the North Yorkshire Police Accident Investigation Unit which has recently started to use Datron's VERICOM equipment. He's seen many accident scenes during his career and knows how long accident investigations used to take using traditional generic testing methods. He may have only been using Datron's VERICOM/load cell technology a few months, but he's already an advocate, though he would be the first to admit that he's still a novice when it comes to getting the maximum out of this new technology.

Currently North Yorkshire Police are principally using the VERICOM VC4000 for ascertaining speed referencing, coefficient of friction and skid-to-stop timings. However, the force is working with Accident and Investigations Training Solutions (AITS) to expand its knowledge of the technology and will be attending further training courses in the coming months.

So how are North Yorkshire Police currently using load cell technology to investigate road traffic accidents?
"In the past what we used to do when vehicles collided and spun across the road, was estimate the speed using generic testing so that we could work out roughly what level of grip the vehicle was putting down on the road and work out a rough speed based on momentum exchange. You could never be absolutely sure that the figures you eventually calculated were completely accurate, but it was the best we could do at the time. In accident investigations now we don't need to estimate the speed of travel, as our equipment is accurate and reliable."

"What Datron's VERICOM system allows us to do is to utilise a load cell. So what we do is to take the crashed vehicle back onto the same road and apply a load cell in line with a winch mounted on the Police Land Rover and then drag the vehicle along the road. What we actually do then is measure the amount of resistance, or in other words the skid resistance of the vehicle as it is in its crashed condition. This gives us an ‘accurate' figure to work with, not the estimates we used to rely on. Other people have tried to use load cells by dragging them behind the vehicle, but we think that's risky and could cause damage. With our method we can effectively put the load cell in line with the crashed vehicle. This gives us full control over the equipment and also gives us much more accurate information."

How do North Yorkshire Police use the VC4000 in practice?
"I recently investigated a crash involving a motorcycle which had collided with a tractor and sheared off all the tractor's front balustrades weighing between forty and fifty kgs. I was able to work out the speed the motorcycle had been travelling at by plotting the various positions of where the motorcycle hit the tractor and where the motorcycle eventually ended up. We did this by using the load cell and dragging the motorcycle behind us. The information you eventually end up with is effectively a percentage of gravity. We quote this figure as a decimal. The tested figure for motorcycles is on average between .42 and 0.45. When I ran the information from the load cell I was given the figure for this particular bike at 0.64 – almost a 50% difference so you then can begin to understand why the crash might have happened."

Why is speed and accuracy so important in your job?
"Testing is vital in accident investigation to make sure that we're absolutely certain of our facts. It just isn't safe to make assumptions or best guesses. We have to accurate, but we need to get the roads back open as soon as possible so we need a fast, efficient and easy to use system. VERICOM provides that. If you want to be absolutely accurate then nothing beats real testing with the best technology and Datron's equipment is without doubt the best there is."

"We only recently started using load cell technology in our investigations. We didn't have the ability or equipment to do it before, but Datron's equipment has now given us access to this. The VERICOM system means that not only can we read all the data accurately, but we can also record it and present this information in evidential form. We can print off and store all the information and we can also present the whole file in court. The judge can then see exactly what we've done and how we've reached our conclusions. Datron's VERICOM system now means that we can take cases to court in full confidence knowing that the information we're presenting is accurate."