Car data recorders aid police investigations
Trace Christenson , Battle Creek Enquirer April 20, 2017
(Photo: Trace Christenson / The Enquirer)
When two cars collided on North Avenue in August the first officers at the scene believed one driver had slowed and was attempting a left turn into the driveway of a golf course in front of another.
That wasn’t the case, investigators determined.
Instead one of the drivers was speeding and drifted across the center line, causing her car to collide with the second car. The first driver was charged with driving under the influence of alcohol.
Earlier this year two men died in Battle Creek when their car left Dickman Road and struck a bridge on Capital Avenue and rolled into the Kalamazoo River.
Police, as they tried to determine the cause of the crash, began calculating the speed of the vehicle based on the amount of damage to the car.
Accident investigators had an estimated speed but then confirmed it when an event data recorder was removed from the wreckage. It showed the car was traveling 98 mph four seconds before the crash and 62 mph when it hit the bridge.
Event data recorders, nicknamed black boxes, have been installed since 2014 in all new vehicles. The National Transportation Safety Board requires they store 15 pieces of information.
Data recorders have been in cars since 1994, providing some information to manufacturers when the air bag deploys in a crash.
The recorders are now a regular part of accident reconstruction, according to local police.
The Calhoun County Sheriff Department purchased a retrieval system in 1998, said Detective Sgt. Steve Hinkley, an accident reconstructionist, to collect data from the recorders and share its use with Battle Creek officers trained as accident investigators.
“We were getting just a couple of cars here and there,” he said. “The information was new and the downloading equipment was new. But we could see that this type of data was up and coming for accident reconstruction.”
The retrieval equipment, including cables for all makes of vehicles, and the software can cost upwards of $20,000.
“The whole process is expensive and we have a lot of money invested, but the return is unbelievable data,” Hinkley said.
The data recorded includes vehicle speed, braking, seat belt use, engine speed, throttle percentage, steering angles, air bag deployment and if lights are on, he said. They are connected to the seat belt module and when an event occurrs, the recorder preserves the data for several seconds before an impact.
“A lot of what we see is on deployment events,” said Cpl. Andrew Olsen, an accident reconstructionist with the Battle Creek Police Department. “It sends a message that all this stuff is happening and we need to deploy the air bag and it captures those events and what causes it and it backs it up.”
The recorders are small modules containing microcomputer chip sets and are part of the airbag control module. They originally were installed to insure that the airbags deployed on time.
Gradually as the design improved, the modules collected more data, stored in a loop until a crash when the last several seconds, usually between five and 30, is stored.
The recorder is placed in the center of the car, often under the driver’s or front passenger seat, because it collects side and rollover data and “everything rotates around the center mass in the heart of the data-collection area,” Hinkley said.
After a crash, reconstructionists like Hinkley or Olsen must climb into the wreckage, sometimes cutting through the seats and console, to attach cables to the device or remove it from the vehicle and collect the data on a computer.
There is some debate about who controls the data. Both Hinkley and Olsen said their departments always obtain court-ordered search warrants before obtaining the data.
“We pull every EDR from vehicles,” Olsen said. “We go in and get the physical module so we have it as evidence.”
The recorders are generally protected from damage, including from water or fire, Hinkley said.
But as good as the recorders have become, Hinkley and Olsen said they are only part of a reconstruction.
“This is not the saving grace or just, ‘here is the information.’ This is a component of the crash reconstruction process.”
Hinkley said he usually collects other data manually before using the event data recorder to confirm his findings.
“Car accidents, as tragic as they are, are basically a science project,” he said. “They are two blocks that have weight and speed and direction and you apply physics to try and determine why and how and the vehicle speeds. We want to find several different methods to find out how fast the car was traveling, for example. This is one of the methods we look at to show consistency with applied physics.”
Hinkley said some of those methods are not exact, like when investigators have to use tape measures on windy cold days or drag a weighted wheel across pavement or even measure the length of a skid mark on dry pavement.
Skid marks, he explained, are created from smeared tar heated by skidding rubber, which must skid several feet before they are hot enough to begin leaving marks.
At that crash on North Avenue last year, Hinkley said he found clues at the crash scene that showed the at-fault driver was not slowing to turn into the driveway.
“And downloading the data from that (event data recorder) was consistent with the physics.”
The event data recorders can confirm what investigators believe happened at the crash.
“You can tell if the driver is accelerating or braking and with new cars it shows the steering wheel angles and degrees,” he said. “We had a case where a driver who hit a pedestrian head-on claimed he swerved abruptly but we found that to be impossible because we could show no steering was applied.
“It shows one degree one way,” Hinkley said. “We can show he was drifting and perhaps was intoxicated. We probably couldn’t see it from the physical evidence but we could see it in the previous five seconds.”
“We use it as a double-check,” Olsen said. “We do our measurements and our investigation at the scene and complete our calculations. We use it as confirmation.”
Hinkley said the data collected is accurate, though not everyone agrees.
“I think it’s mystery meat,” said J. Thomas Schaeffer, a Marshall defense attorney, who has defended some traffic-crash cases.
“Like any of the other things you have a group of people who are into that science and they believe it. The data recorders are a product of the computer age and someone writes the program and the people locally are just inputers into a computer program and it regurgitates the results. My experience is that the locals don’t have a clue scientifically what it means.”
Schaeffer said his discussions with other experts is that sometimes investigators do the scientific work incorrectly, even if they obtain the correct results.
“It is only as good as the science behind it and I think the science is early on and I have cases where the results are not rationally acceptable as to speed. I am a suspect of that, but then I am a suspect of DNA too. It is all an evolving science and hopefully it will be more reliable as time goes by. But every time we have a Ph.D. thesis on a particular subject everything changes. Butter was bad, but it is good for you now. This is all subject to the same problems.”
Schaeffer is skeptical when experts testify about the data they obtain from a black box without being convinced of the science behind it.
“I think it is an evolving science and I don’t think it is a given,” he said. “There is a lot of science that is not 100 percent. If we are convicting people on science that is not 100 percent, then there will be a percentage of convictions that are wrong and improper.”
Hinkley and Olsen said they are convinced the data recorders are reliable.
“When we get our data and our estimates and calculations they are right there in those ranges,” Olsen said. “It is a good confirmation. We don’t just do it off the computer. We have to do it the old-fashioned way but the more data we have the better. It is a good tool to have. Another tool in the toolbox.”
And Hinkley agrees that the EDR are used in this county to support conclusions by reconstructionists.
“It is independent and unbiased and more and more people expect this type of information and this type of data,” he said. “It is an incredible tool to see what and why it happened. Of the 250 cars I have downloaded I have always felt comfortable with the data collected.”
And he said when crashes become court cases, the data is important.
“People just expect it,” he said. “Attorneys expect it. Did it have a crash data retrieval? Then let’s see it.”
Contact Trace Christenson at 269-966-0685 or firstname.lastname@example.org. Follow him on Twitter: @TSChristenson
Detective Sgt. Steve Hinkley digs into the wreckage of a car to
retrieve the event data recorder. (Photo: Trace Christenson/The Enquirer)
Andrew Olsen of the Battle Creek Police Department pulls the crash data recorder
from one of the vehicles involved in a crash on M-66 and B Drive North last year.
(Photo: Trace Christenson/The Enquirer)