How collision reconstructionists put the pieces back together after a fatal crash

Saskatchewan has had a number of fatal crashes on its roads over the past couple of weeks.

On July 16, Mounties responded to a crash just east of Outlook where a car and a motorcycle collided, leaving two men, ages 57 and 99, dead.

The following day, Prince Albert police released information on an incident where a pedestrian was struck by a vehicle. The 58 year old who was hit died a few days later in hospital.

Read more:

• Highway incidents claim two lives on Wednesday: RCMP
• Norquay man, 50, dead after rollover on Keeseekoose First Nation: RCMP
• Sask. RCMP briefs: ‘Serious collision’ on Hwy 1, police arrest man after La Ronge shooting

On Sat, July 18, Mounties shared information of a crash on Highway 11 near Lumsden, where two SUVs collided. The Saskatchewan Roughrider’s Jayden Dalke, 30, and 22-year-old Bhishma Rajyaguru both died in the crash.

Sergeant Tanner Maurice is the Regina Police Service officer in charge of the investigative collision analysis and reconstruction team. He joined the Evan Bray Show on Tuesday to discuss the inner workings of these investigations, and what methods officers use to find the answers once those emergency response vehicles leave.

Listen to the interview with Sgt. Tanner Maurice here:

This transcript has been edited for length and clarity.

EVAN BRAY: What are the considerations for you as an investigator and your team when you’re approaching a collision scene like this? What are you looking for?

SGT. TANNER MAURICE: We do obviously deal with tragedies, but at that moment, we just kind of have to set that aside and we take a very scientific approach to investigating the collision. So, as concisely as I can describe it without sounding dramatic, the first thing I want to do is get on scene and let the scene and the evidence speak to me. I really don’t know any other reconstructionists who prefer to kind of even speak with an on-scene officer or witnesses without themselves getting to walk through that scene first.

I know many people will talk about the challenges of investigating a crime scene or an accident scene, a collision scene like this, when it’s happening in darkness because some of the evidence, the roadway evidence, will disappear, will lighten and will change over time. Am I right about that?

MAURICE: Yeah, it can. I mean, things like skid marks can disappear, but they’ll stay on scene for a little while, and obviously that’s why we use 3D laser scanners, we use drones and we use people who are very well trained in photography so that we can kind of digitally revisit that scene and check it out in different lighting as well.

So when you arrive on scene, can we talk a bit about all of the different pieces of evidence that you would be assessing, you would be looking at and you would be taking note of?

MAURICE: Every scene is going to be different, but at the end of the day, we have objects that have collided – whether that’s two vehicles or a vehicle and something else, a vehicle and a pedestrian – and so, let’s say it’s a two-vehicle collision. I’m going to be looking at the damage profiles of the vehicle – that’s going to help maybe give me an idea of what the inward angles were and the departure angles when they left the moment of impact. Looking at tire marks on the ground and metal gouges, there are a lot of metal components on vehicles and those metal components don’t typically touch the ground, but in a collision – just due to the forces and gravity – a lot of those will gouge into the roadway, and so that can be very useful to us, as well. We’re looking at all sorts of sight lines and angles because, ultimately, when we reconstruct these collision scenes, we have to be able to kind of answer the question: Could this have been avoided? When could these two parties have possibly even seen each other, if they could have at all? So there’s a lot that goes into it, and that’s why there are such lengthy investigations.

Is it possible that there are no skid marks in some collisions that you investigate?

MAURICE: Absolutely. I mean, we kind of break it down into pre-collision evidence and then kind of the area of impact or the moment of impact and then post-collision. So oftentimes, depending again on the very dynamic nature of these things, sometimes there is no pre-collision evidence. The first piece of evidence we see is where these two objects collided.

If there’s no pre-collision evidence – that would mean no skid marks – I guess, what does that tell you?

MAURICE: When you see a skid mark leading up to a collision, you can usually infer that you know it was an avoidance-type maneuver, and so that even allows us to kind of figure out how far back in time and, talking speed, how far back somebody noticed an imminent threat. When you don’t see any scrub marks from steering, swerving or any braking, it typically – again, very generally – leads us to believe that you know these parties didn’t perceive each other as a threat or didn’t comprehend the threat.

If there’s a piece of a vehicle, a tail light or something that is a distance away from the vehicle, how important is that evidence?

MAURICE: Depending on what it is, we can start to gather speed, but really a lot of directionality, as well. Which way vehicles were going and the angle at which they collided can help us determine maybe who’s at fault or who was coming from where, because everything that flies off a vehicle has to adhere to the laws of physics. So we are able to kind of work backwards through some of those items. I mean, they’re not the smoking gun that maybe some TV shows would have you believe, but certainly they are useful to us.

Can you talk a bit about electronics in a vehicle? Do modern vehicles have something in them that helps investigations?

MAURICE: The important thing to recognize is that any vehicle in Canada after 2012, I believe it is, will have what people typically refer to as a black box. But the thing is, it’s not designed for police investigations. It’s an automotive tool designed for diagnosing vehicles. But we are able to access that information and, quite honestly, glean a lot of information from there, so we will get things like the speed of each individual wheel. So if one wheel is traveling much faster than the other, that’s an indication that perhaps it’s off the ground and no longer in contact with the ground, or at very least it’s slipping, meaning it could be hard acceleration for one of the wheels. We get steering angle input, we get braking – all types of information that can be matched up with roadway evidence. I’ve worked a couple cases, Evan, where I’ve literally been able to break down a collision scene in tenths of a second and tell you what inputs were going into the vehicle and what that vehicle was doing on scene.

Can you talk about eyewitness statements that might have been given? At what point do you, as an investigator, look at those, or do you look at those during the course of the investigation?

MAURICE: We certainly do. But I can tell you that for collision reconstructionists, that comes quite a bit later. Eyewitness testimony is valuable to us, and we do appreciate when people stick around or provide their information. But generally, what we have to do is kind of take multiple different accounts from witnesses and look for the things that are similar and corroborate things. Every individual account is bound to have a couple things that maybe didn’t quite happen as somebody perceived or remembered, so it is useful, but it’s later on in the investigation, and it’s only used to corroborate what our math and our physics will already have shown us.

When you’re working on a collision scene, are you trying to determine who’s at fault or are you trying to determine what happened?

MAURICE: It’d be way more appropriate to say that we’re simply trying to determine what happened. We know that some objects have come together. Certainly, we are taking into consideration the laws of the roadway, the Traffic Safety Act, and also criminal elements, such as dangerous driving. But first and foremost, it’s really just what happened, and then we look at all parties. Even let’s say the party that is “at fault,” we do a time-distance analysis, a collision-avoidance analysis. Could they have actually done something to avoid the collision as well? Did they perceive this imminent threat?

How much responsibility do you feel to get the details right when, essentially, there are no survivors of the crash to help provide some answers?

MAURICE: It’s absolutely paramount, and it really is what drives my passion for doing this. I think I’m speaking for all collision investigators, trying to find out what happened so that we can tell the families of these individuals who’ve lost their lives exactly what went down. If it is something that’s going to be useful for them, that’s important to us. Knowing that someone has taken care to kind of piece together someone’s last moments can be very cathartic for people.