North Yorkshire police use Datron’s VERICOM equipment to guarantee accuracy in accident scene investigations
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."