How do you get evidence about the speed of a car from cracks in the pavement or trees at the corner? How do you get reliable, quantitative evidence from the qualitative data on a mobile phone? Evidence that will stand up in court?
This is being done now by a new forensic investigation method. It requires knowing what to look for in the phone’s video, some measurements with a carpenter’s tape, Google earth, a little junior high math and lots of software.
It’s called video velocity analysis, a scary title but remember: Carpenter’s tapes, junior high math and modern technology make it happen.
Video of aircraft accidents taken by witnesses has been analysed since 2008. The crash of TransAsia flight 235 on February 4, 2015 in the Keelung River shortly after takeoff from the Taipei Songshan Airport was caught on three separate witness cameras, and was subsequently analysed. Video of traffic accidents is now being done the same way.
Reliable forensic evidence
The qualitative data on traffic cameras and car dashboard cameras is also being used, as well as mobile phones to learn the speed of a car at the time of an accident. In fact, it was the cross checking of an assessment of car speed from three different sources of soft data - mobile phone, traffic camera and dash camera - in field trials with a car with a speedometer and GPS, that has demonstrated the accuracy of this new method.
How accurate is an assessment of car speed using these types of simple cameras? Depending on the circumstances, within about 2 km/hour – pretty hard evidence in a court case.
Google Earth sometimes figures in this type of assessment as well. How accurate is the quantitative data from the eye in the sky, kilometres high? How about within a few centimetres on the ground in urban areas.
Evidence based on junior high math
The basic principle is simple enough. Measure the distance between two points on the ground seen in mobile phone video, note the time on the video for the car to travel this distance, divide one by the other – junior high math – and you’ve got your car speed. Photogrammetry, the science of making reliable measurements using photographs, is sometimes used in this work but the principle is simple.
What does the analyst look for in the mobile phone video, traffic camera or dash camera? Basically, anything on or near the ground that can give distance that can be correlated with time which is also taken off the camera. Things like the distance between construction cracks in the pavement, dashes on road centre lines and lane markings. The analyst is also interested in anything that can be seen on Google Earth.
Car speed in accidents has been measured other ways for years and continues to be. Using mobile phones is new, can be more accurate and provides an opportunity for the cross checking essential to good engineering and applied science. I had the cross checking of data drilled into me by Major James A. H. Church when I studied land surveying at the College of Geographic Sciences. (Ref. 1)
Explained in Moncton, NB in 2017
This all came out in a lecture I took last fall in Moncton by Major Adam R. Cybanski, Gyro Flight and Safety Analysis, Ottawa, on a new technique for learning car speed in an accident. (Ref. 2)
Major Cybanski has been instrumental in developing the technique using the simple, inexpensive mobile cameras that are everywhere today. He specializes in video analysis and accident reconstruction for aircraft and auto accidents. Adam flew all manner of aircraft in the air force over the years, slowly moved into the investigation of the cause of aircraft accidents and more recently into auto accidents.
And used in court cases
He believes he is one of a few in the world using this analytical technique. In 2016 he had one case, but this grew to 14 cases from different accident sites in the world in 2017. Video speed analysis has been used in several court cases and as of March, 2017 has not been contested.
An analysis took him many months initially when he was developing the technique using witness video. It is something he can now do in a few days, depending on the location of the accident and the features visible in the video. Time is spent cross checking an analysis; getting the car’s speed from more than one camera.
Vehicle speed is just one element in accident reconstruction but an important one. Adam gets camera data sent to him from the principle investigator wherever he or she is in the world, analyses the data and sends the auto speed back to the investigator. He doesn’t need to visit the site in most cases. His speeds have been validated using speed radar guns, GPS and Event Data Recorders – the “black boxs” installed in some cars to get information during accidents.
The lecture was organized by CATAIR, the Canadian Association of Technical Accident Investigators & Reconstructionists, Atlantic region. Dr. Stuart Smith, secretary of CATAIR knew of Major Cybanski and his technique and suggested inviting him to Moncton to speak. Stu reconstructs traffic accidents in his practice including analysing vehicle speed. (Ref. 3)
What’s the take-away from this blog? A new and accurate method is available to check vehicle speed in an accident as determined in more conventional ways. The results are reliable and accepted as evidence in court. And expertise is as near as your e-mail. The speed of anything that moves can be analysed if caught on a mobile camera.
- Church, Major James A. H., founder and first principle of the Nova Scotia Land Survey Institute, 1947, forerunner of the College of Geographic Sciences, Lawrencetown, Nova Scotia
- Cybanski, Major Adam R., Gyro Flight and Safety Analysis, Ottawa, 2017 http://www.gyrosafety.com (Adam and I conferred about this method as it’s new to me too)
- Smith, Dr. Stuart, C. R. Tyner and Associates, Dartmouth, Nova Scotia email@example.com