Darien police use technology, math to solve accident cases
Published 1:51 pm, Thursday, June 9, 2011
Investigating an accident scene may seem like a straightforward process, but when you factor in weather conditions, contaminated evidence and the fact no accident is ever the same, the incident becomes significantly more complex.
Sgt. Jeremiah Marron, public information officer and accident investigation team member, said investigating an accident is a time-consuming process because officers must make sure all of the evidence is properly handled and the incident is as faithfully reconstructed as possible.
After receiving a $20,000 grant from the Darien Technology Fund, the department was able to purchase almost all of the equipment used in investigating
accidents, Marron said.
"We're one of the most well-equipped departments in the region," he said.
The department's equipment is essentially what a land surveyor uses. Officers are able to determine elevations and angles as well as pinpoint evidence around the area using GPS technology, Marron said.
After gathering all of the evidence from the scene, officers plug the data into a database and create a scale replica of the crash scene.
"We use the survey equipment to shoot a bunch of different points and then upload the data," Marron said. "Then we have an exact scale replica and we can place the vehicles into the scale to get a better idea of what happened."
Even though the equipment is readily available, not all accidents require its use. However, there are instances where the equipment can help to determine why multiple accidents are occurring at specific locations, Marron said.
"We can map out intersections to figure out why the area is so dangerous and then make suggestions to get the issue resolved," he said.
The Accident Investigation Team also has access to a drag sled which is used to determine the frictional value of surface so officers are able to determine the acceleration and deceleration of a vehicle.
"When we went to that accident on Mansfield Avenue we had to compute the frictional value of the grass as well because both vehicles ended up leaving the roadway," Marron said.
The computer systems used in vehicles also hold valuable information; however, a search warrant must be filed before officers can remove the computers, Marron said.
The systems store data from five seconds before the air bag is deployed. Officers can determine how fast the vehicle was traveling, how much throttle was being applied, whether the driver was wearing a seat belt and if any braking was applied before the impact.
With all the technology available to assist in the investigation of accidents it may seem the process is simple and straight forward. However, a number of variables can impact how quickly an investigation moves forward, Marron said.
One of the biggest issues which can slow down an investigation is if an accident occurs in extreme weather, Marron said.
"If an accident occurs in extreme weather it can be difficult to replicate the conditions and we need to be able to find the exact weather report from that day," he said.
When an accident happens during the winter it can also be difficult to gather all the evidence because the snow doesn't always hold tracks or skid marks.
The weather can make the investigation more difficult, but there hasn't yet been an instance where officers couldn't determine an answer for why an accident occurred, Marron said.
"Extreme weather just increases the number of steps we have to take," he said.
Other issues that may arise include evidence becoming contaminated as emergency personnel working to free a person from a vehicle.
There are also times when the equipment can fail and officers are forced to revert back to using tape measurers and writing down their calculations, Marron said.
It is important to officers to get the most accurate picture possible because there are often charges filed as a result of the accident.
"We've had investigations where the non-at-fault operator was arrested on other charges," Marron said.
"We're not trying to provide information for a civil case. We want to determine what happened and how to prevent it from happening again."
Marron said the department wants to conclude investigations as quickly as possible but it is important a thorough job is done because people's lives could be impacted, especially in cases where someone is arrested.
Fatal accidents are less common in Darien, but one of the goals for the department is to reduce the number to zero.
Marron said there have been times where the department is able to make a suggestion to have a traffic light installed or a road regraded to make it safer for travel.
"We went from an average of three or four fatal accidents a year to not even one," Marron said.
Even though every accident is different there is a common trend involved in almost every case.
"Most accidents are 99.9 percent due to driver error or speed," Marron said.