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."

One of the most important activities of Road Policing occurs when there is a fatal or life-threatening road traffic collision on the network. In such instances, the Police are required to investigate the circumstances to the highest possible standard: a thorough investigation process is necessary to ensure that all the legal obligations are met, and that every last piece of evidence is efficiently gathered for any due criminal process that might follow. Generally the Police will have a limited time-frame in which to gather all the necessary evidence, as it is important to re-open the road network as soon as possible: however, there is a fine line to be drawn between re-opening carriageways for the convenience of the motorists, and ensuring that no piece of evidence is overlooked.

The Police use incident scene surveying equipment during collision investigations to collect comprehensive surveys of the scene, which can then be effectively used in all legal hearings, from Coroners and Criminal Courts to Civil Litigation Hearings. This equipment can help measure the angles between points using GPS; this data is then downloaded and converted into a scene diagram. GPS enabled equipment is especially useful as it is both quick to use and extremely accurate, thus avoiding the need for extensive road closures. Research has shown that the use of GPS at collision investigations can speed up survey times by as much as 5-6x.


GPS technology is constantly evolving: each innovation only serves to make crash and collision scene investigation ever more accurate. The VERICOM 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, coefficient-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.

In addition to the standard braking and acceleration testing, some Police Forces are also using the VERICOM DAQ (Data AcQuisition) models to undertake more complex testing functions, such as Air and Hydraulic Brake pressure recording on HGVs and LGVs to determine the effectiveness of the braking system. Up to 12 additional sensors may be connected to VERICOM DAQ models to allow data to be recorded simultaneously with the braking parameters.

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; this is vitally important when the case proceeds to court.

Throughout the UK Police Forces are equipping their Collision Investigation Units with VERICOM Brake and Dynamics testers from DATRON TECHNOLOGY.
A total of 18 Police Forces in England,Wales and Ireland are now using the VERICOM VC3000 & VC4000 products with several more planning to order in 2010.

The Vericom instruments offer many advantages over the types of Skid Testers and Decelerometers that have been in use by Police C.I.U's for many years.Having Dual and Tri-axis accelerometers built-in Vericoms are able to measure not just vehicle Skid-to-Stop and Road Friction Co-efficent but also vehicle accelerations to set speeds,between set speeds and also over time and over distances which are defined by the user.

In addition to the standard braking and acceleration testing some Forces have purchased
VERICOM DAQ (Data AcQuisition) models to undertake more complex testing functions such as Air and Hydraulic Brake pressure recording on HGV's and LGV's to determine the effectiveness of the braking system.
Up to 12 additional sensor may be connected to the Vericom DAQ models so the data from these sensors will be recorded simultaneously with the braking parameters.


Other applications for which the Vericoms are being used are………….
# Motorcycle braking and acceleration testing,including Horsepower calculations to establish if a bike has been de-restricted.
#Recording forward and lateral accelerations over short distances when pulling out from a T- junction. 
#Brake pedal pressure and travel recording during braking.                                                                                                           #Using the GPS sensor data (optional on VC4000PC & DAQ models) for geographical location data where tests are done.

and many others……………………………….

For the latest information and prices on the Vericom VC4000 range or if you would like a demonstration and evaluation contact the Datron team today.

Datron exhibitied at the Institute of Traffic Accident Investigators (ITAI) Conference and Exhibition on 26th/27th September 2009.The event,which takes place every two years,was at the Hinckley Island Hotel,Hinckley, Leicestershire,U.K.and was held in conjunction with the German-based EVU,an allied organisation.Papers were presented by scientists and practitioners from both organisations to delegates from all parts of Europe,North America and the Far East.
Datron exhibited the VERICOM range of testers together with the OXTS RT and Inertial+ dynamics and survey products.

The VERICOM VC4000 range is the latest in a line of products in use by Accident Investigators for over 25 years worldwide.On show were the VC4000PC and VC4000DAQ models together with their accessories and the Profile4 analysis software.
The VERICOM Testers are now in use by many Police Forces in the U.K and Ireland.They offer many more functions than the traditional skid-to-stop testers including acceleration tests,GPS data,lateral G measurement and many more.
The VC4000DAQ model has inputs for up to 12 additional sensors so for example can be used to record pressure data from air brake systems on HGV’s.

Also examples of the OXTS RT2500 and Inertial+ products were exhibited.The OXTS products have applications for some of the more  unusual measurements in accident investigation;for example a coach roll-over accident.
The OXTS products are also used by many organisations for surveying road surface quality,road system infrastructure and also in aerial survey work.

DATRON offer an Instrument HIRE service of both Vericom and OXTS products.This is ideal for those practitioners who do not have a constant requirement for test instruments.        Call us today for hire prices and to reserve a unit.

Datron are pleased to be the sole UK supplier of the VERICOM VC3000 & VC4000 range of instruments which are used in Collision Investigation for measuring and recording deceleration,coefficient-of-friction and skid-to-stop testing.
These outstanding products have been developed over many years in the USA in close co-operation with police and university establishments.
They are in use by Police Collision Investigation Units (C.I.U) throughout North America,Australasia and many other parts of the world.
The VERICOM is quickly becoming the instrument of choice of many UK Police C.I.U's throughout the country.

There are several basic products available today for braking and coefficient of friction measurement.The feature-rich VERICOM goes much further by having many additional measurement functions such as forward acceleration measurement,lateral acceleration
measurement, instant viewing of test results and large data memory; to name just a few.

A unique feature of the VERICOM is it's Run Duration Protocol (RDP) function.Many deceleration testers measure the deceleration from (typically) a minus 0.2G falling trigger point through to a rising minus 0.2G stop point.This does not give true test results because the measurement should stop when the vehicle speed is zero and not when the deceleration reaches the minus 0.2G rising point.This can be responsible for a considerable error in the calculation of deceleration,speed and distance (i.e. inaccurate data).By using a VERICOM with it's RDP function collision investigators can be confident that their test data is completely accurate.

Using the VERICOM DAQ models it is possible to input signals from sensors which will be integrated with the basic time,deceleration,speed and distance measurements.One typical application is recording pressure information from sensors attached to points on HGV air brake systems.Another is measurement of brake pedal force and travel. 

It is very important for Collision Investigation Officers to be able to provide comprehensive and accurate data in a courtroom situation.
Using the VERICOM computer-based data analysis software officers can easily integrate graphs and numeric data into their accident reports to give clear and concise evidence.This is very important in securing convictions enabling many reckless and dangerous drivers to be kept off UK roads.
DATRON are pleased to be able to support UK Road Safety in this small way.

A comprehensive two-day training course in the use of VERICOM products in Accident Investigation is now offered by the  Accident Investigation Training School (A.I.T.S.).Information is available by logging on to www.aitsuk.com or call 01285 864650.

If you are a Police C.I.U. Officer or an independant C.I practitioner and want to know more about the VERICOM please call Datron today for full product information and to arrange a demonstration/evaluation.