Episode 19: Conversation with Steve Grundhoefer (Accident Reconstructionist)

Steve Grundhoefer:

You see the end results of a crash, and look at the evidence that’s on the road, look at the evidence that’s the vehicle and try to piece together the events what led up to this crash, and come up with the positions of impact, the speeds of the vehicles, and the approach of the vehicles. So, it’s like solving a puzzle using your background in physics and math and training and accident reconstruction.

David Craig – Host:

Today, I’m fortunate to have Steve Grundhoefer as a guest. Steve is a licensed professional engineer. He does traffic accident reconstruction. He has extensive experience doing what we call forensic work. He is ACTAR accredited. He’s Crash Data Retrieval System Operator Certified. He started off working as a civil engineer in road design, and then he went into the forensic world and started doing accident reconstruction. He did it for another company for quite a while, and then he started his own business.

David Craig – Host:

This is After the Crash. I’m attorney David Craig, managing partner and one of the founders of the law firm of Craig, Kelley & Faultless. I’ve represented people who have been seriously injured, or who have had a family member killed, in a semi or other big truck wreck for over 30 years.

David Craig – Host:

Following the wreck, their lives are chaos. Often, they don’t even know enough about the process to ask the right questions. It is my goal to empower you by providing you with the information you need to protect yourself and your family. In each and every episode, I will interview top experts and professionals that are involved in truck wreck cases. This is After the Crash.

David Craig – Host:

Welcome, I really appreciate it. Steve and I have had opportunities to work on many cases together, and in fact, we spent three days here recently in the cold and rain out doing a reconstruction. Then, on the other hand, I’ve had the occasion to work with Steve on the opposite side of me. Let’s just start off talking a little bit about your background, and if that’s important, and why is it important?

David Craig – Host:

You have a bachelor’s degree in civil engineering, not all accident reconstructionists are engineers. Do you think there’s any advantage to the fact that you are an engineer? How do you look at things differently, maybe?

A Civil Engineer as an Accident Reconstructionist

Steve Grundhoefer:

Yes, my first job after I got out of college was that I went to work for a road design firm. There, you learn some of the fundamentals of road design, sight distance, the grate of the roadway, and geometrics of the intersection. So, that has really helped me when I look at an accident because I look at those things. It could be, what is the sight distance of the roadway? Is the curvature of the road proper? Is the intersection laid out properly?

Steve Grundhoefer:

So, as an engineer and having that background, I think that helps me when I’m looking at the scene of an accident, or things that maybe a normal person would not be looking for. Of course, with the engineering background, you get all the physics. It’s not just the physics of accident reconstruction, but you learn all that math, physics, and things like that. You just get more of an understanding of the mathematics and the physics that go into traffic accident reconstruction.

David Craig – Host:

I think, nowadays, I mean, for several years, I was taking depositions of reconstructionist that the defense might hire, that weren’t really that good at reconstruction, but they retired from the police, or they retired from some other area and chose to go into that. Some of them weren’t even police officers. Some had no background, but I thought, “Well, this is a lucrative area, so I’ll go into that.”

David Craig – Host:

The thing that struck me, they weren’t engineers. They would use computer programs to determine things, how an accident happened, the speed and those type of things. When you actually ask them to sit down and explain to you the formulas or how that works, how did this computer program come to these conclusions? There were a lot of people who didn’t know that.

Steve Grundhoefer:

Yes, that’s one of the fallbacks. If they give you these powerful programs, but you do have to know the physics that goes into it, that you are inputting the proper data and that this accident fits the formula you’re using because I’ve seen a lot of times, you’re using totally the wrong formula for this this type of crash.

Steve Grundhoefer:

So, having that background in engineering does help you understand everything, the physics and the math, and when the formula applies appropriately, and when it doesn’t, and what factors in the equation really affect it the most. If you have the weight of a vehicle or the angle of approach, what are the key factors that are more critical in the analysis.

David Craig – Host:

Certainly, there are other people who have learned that and understand the formula really well. They’re good in math. Certainly, in engineering you have to, in order to get the degree, you have to understand what’s going on in the formulas. I think that certainly gives you an advantage. Tell us a little bit about ACTAR accredited. What does that mean?

What Does It Mean to Be ACTAR Accredited?

Steve Grundhoefer:

I’ve got my professional engineer’s license in Indiana and Kentucky, but it’s specific to accident reconstruction. It’s the PE exam for accident reconstruction, where you take an exam, it’s a written exam of eight-hour duration, where the first part is question and answer, true and false about accident reconstruction. Then, you physically have to work a problem using the old-fashioned techniques, conservation of momentum or energy to come up with the answer to solve the accident. So, it shows your knowledge in the field of accident reconstruction.

David Craig – Host:

And I know that… I mean, not all reconstructionists are accredited through them, is that correct?

Steve Grundhoefer:

That’s correct.

David Craig – Host:

And it’s kind of like attorneys. I mean, I do semi wreck cases. I’m board certified in semi wrecks, which means that I had to have a certain level of experience. I had to have certain people vouch for me, judges, defense lawyers, experts. On top of that, I had to take a test and pass that test and keep up in my area of expertise.

David Craig – Host:

But, again, not all lawyers are board certified in truck accidents. So, it gives you that extra reassurance when you’re picking a reconstructionist. You can look and say, “Okay, was this person ACTAR accredited?” So, you certainly, have that. You’re a professional engineer, so tell us a little bit about what’s required to become a professional engineer?

What’s Required to Become a Professional Engineer?

Steve Grundhoefer:

Okay. I graduated from Purdue University which was a four-year accredited college. So, after that, when you get to the end of your schooling, you take what they call EIT, the engineering and training exam, which covers every field of engineering a little bit. So, it’s a little more difficult class because you actually took parts of electrical engineering, which I had no classes in, and you had to answer questions in other fields.

Steve Grundhoefer:

If you pass that exam, then you got to get five years’ experience in the field. You can apply for and take your professional engineer’s license, and that’s another eight-hour exam and continuing it after that.

David Craig – Host:

So, you’re a glutton for punishment, taking all these exams?

Steve Grundhoefer:

Yes. I was glad when that one was over.

David Craig – Host:

Now, and so, you got your professional license in multiple states. So, tell us again, what states do you have your professional license in?

Steve Grundhoefer:

Indiana, Kentucky, Tennessee, Ohio, and Illinois. I had Michigan, but I don’t go up there anymore, and I just let that one lapse.

David Craig – Host:

Let’s talk a little bit about how you have your own company that you run, in what areas of the country do you work in, primarily?

Steve Grundhoefer:

I’m primarily in Indiana and Kentucky.  They’re probably 85% of my work. I do some in Illinois, and then also in Ohio. I’d say Indiana and Kentucky are majority of my work.

David Craig – Host:

I think I introduced you by stating that I’ve had cases where you’re on my side, and then, I’ve had cases where you’re the expert for the other side. So, talk a little bit about that. Do you do work for both sides of what we call the V meaning that you represent victims of wrecks as well as trucking companies or the drivers, the truck driver, or their insurance carriers.

Steve Grundhoefer:

Yes. When I first went to Donan Engineering, we probably were doing more of the work for insurance companies and ended up being a little more defense work. As I got into the field, I started getting relationships with the plaintiff attorneys and doing more and more work. Right now, I probably am a 50% split between what I call plaintiff and defense work. I think it’s good to have that mixture because basically you give an honest opinion. You look at this thing, and here’s the facts.  Here’s what happened in this crash.

David Craig – Host:

I think a lot of the experts that I use do work on both sides. I think it seems like it makes you a little more objective potentially.

Steve Grundhoefer:

Yes.

David Craig – Host:

You’re not a hired gun for either side.

Steve Grundhoefer:

Yes. Almost every time I look at the case now, I know the attorneys on both sides, usually.

David Craig – Host:

It’s the same way especially in the semi-truck area. First of all, there’s less than 50 lawyers or right around 50 now that are board certified in truck wreck law. So, I know a lot of the lawyers that do truck wreck cases. I know the lawyers on the defense side who defend trucking companies. Sometimes, I’ll speak at conferences where they’re at, and I’m there. So, we talk, and I get to know them.

David Craig – Host:

It’s the same way with experts, I mean, there’s a handful of experts that do these cases on a regular basis, and you’re certainly, one of those. I would imagine you run into the same experts.

Steve Grundhoefer:

Yes, yes. There’s probably, about 15 different experts in Indiana and Kentucky, that I always run into, I know them all quite well.

David Craig – Host:

So, I’m just curious, what got you into forensic work? My dad was a psychologist when he was alive, and he treated folks, and he hated it when he’d get called in and have to testify or do a deposition. He’s like, “Man, I just, never want to do that work.” So, some people just really stay away from it, and other people seem to be attracted to it. Why do you do what you do?

Steve Grundhoefer:

When I first came up, my first job was in that road design. My wife and I wanted to move back to Dubois County where I was from and there was this firm called Donan Engineering, a little small local firm. While I went there, they were doing civil design work like I was doing, some road design, some site design, but then they were doing the forensic investigation.

Steve Grundhoefer:

I’ve got a structural degree, structural engineering. We were looking at a lot of houses, just what’s causing this roof to sag, what’s causing this wall to bow. Then, we started getting calls about accident reconstruction.

Steve Grundhoefer:

So, at that time, it was only me and John Donan, who was the owner of the company and I told them that sounds extremely interesting to me with my road design background, and that, I’d really like to learn more about accident reconstruction.

Steve Grundhoefer:

So, I talked to him, and they sent me up to Northwestern University where the school is a traffic institute and started taking classes in ’96 up there. Like I said, I’d been taking classes. I took I don’t know how many hours of classes through Northwestern. Then, there’s another facility called IPTM, Institute of Police Technology and Management, out of the University of South Florida. They offer courses in accident reconstruction.

Steve Grundhoefer:

The World of Engineers has now come out with very good courses in accident reconstruction. It just always interests me, it’s like putting a puzzle together, you try to take the end results, you see the end results of a crash, and at the evidence that’s on the road, look at the evidence that’s the vehicle and try to piece together the events what led up to this crash and come up with the positions and impact, the speeds of the vehicles, the approach of the vehicles. So, it’s like solving a puzzle using your background in physics and math, and training and accident reconstruction.

David Craig – Host:

I know that you obviously do a great job, and it is exciting to put things together and help solve a puzzle. Today, we solve those puzzles a lot differently than we did 35 years ago when I started. I can just remember it was a little bit more challenging to try to recreate and figure out the speed and a whole bunch of other things.

David Craig – Host:

Nowadays, whether you’re talking about electronic control modules, data that’s saved, video, I mean, it’s just so much different work than what it was, and I would imagine, your practice has changed over the years and equipment you use, I know has changed.

Working with New Equipment

Steve Grundhoefer:

Yes, yes. When I first got into it, we were working for the road design firm. I ran the survey crews for the first three or four years out of college. We had the old tape measures and levels. We’d do all the elevation with a survey level and rod, then we’d have a crew behind, doing what they call topography, measuring with a baseline offset, and we were lucky enough to have one instrument that would record digital distances.

Steve Grundhoefer:

So, gradually at Donan, we started doing accident reconstruction. We got a total station, which was a great tool reflector as one where you could sit up and turn the angles, shoot distances without having to have a rod man. If you got further away, you’d need the prism. Nowadays, everything’s getting more and more digital.

Steve Grundhoefer:

What we used to do with a six or eight man survey crew, I have a drone now that I use with the photogrammetry software PIX4D, where one person can do what an eight man survey crew could do in far less time by just putting out aerial targets, shooting location, those targets, and then flying the scene with a drone, you can create a 3D environment from the photogrammetry using those photographs.

David Craig – Host:

The great thing about capturing these scenes now, the wreck scenes, or accident scenes with 3D cloud point scanning, is that it captures everything. So, if down the road you forgot a measurement that’s more important because somebody says that this was in the way or block their view or whatever.

David Craig – Host:

Back in the old days, if we didn’t measure it, we might not have it because if the scene changed then you’re out of luck. Now, with these 3D scans that are so detailed you’ve got everything, and you can go back into the computer and figure it out and measure it. It truly is amazing.

Steve Grundhoefer:

Yes, that is a great advantage because you get out to the intersection, there might be tire marks everywhere, you may not shoot everything like you said. Also, in this market, what you didn’t happen to shoot becomes very critical with the 3D scan or with the drone and PIX4D, you capture everything, and it’s all to scale, and you can measure it from the point cloud or from the orthomosaic, you create.

Steve Grundhoefer:

So, yes, it’s a tremendous tool, plus, you get a great perspective. I like the drone’s perspective when sometimes the aerial perspective is one of the best things you can see. You can see tire marks. It really might be more difficult to see on the ground.

David Craig – Host:

Yeah, I know you and I are working on a case, and I won’t go into detail about it. It’s a case where, unfortunately, it’s very tragic. Yet, figuring out what happened and why it happened is still part of the job. In that case, you used your drone on the outside of the building. Then, we also did 3D scanning inside the building through a company called Precision Point.

David Craig – Host:

So, it’s fascinating to me that, if you get hired quick enough, then you can preserve the scene through the outside and the inside if it’s a case involving a building.  In this case, a vehicle went through a building, but it’s amazing at the amount of information and data you can collect on the front end of these cases now.

Steve Grundhoefer:

Yes, that’s very critical on a lot of these cases, because you get the cases are 2 years old, and that data wasn’t collected, and you’re trying to work off of photographs that were taken by someone that’s not really trained in reconstruction. The more data, the better job you can do, and the more pieces to the puzzle you have.

David Craig – Host:

And I think it’s important, I think, again, on this podcast, I speak to lawyers, and I talk to lawyers, and they get it. But on the other hand, this podcast really is designed for just the ordinary folks, who have a case and they’re wanting to know things. I believe that if you give them information, it empowers them.

David Craig – Host:

So, regardless of who they hire, who their lawyer is, they know, “Okay, I ought to ask them these questions,” and one of the things is how important it is to preserve evidence. I mean, so when people are sitting there, and their attorney may not be talking about preserving evidence, that’s one of the first things that I do. I mean I understand it and I get it.

David Craig – Host:

I’ve seen what happens when lawyers hire me two years later, and the data is gone, the information is gone, but just for these average everyday folks that are listening to this, talk a little bit about how important it is to be able to get there quickly and preserve the evidence.

How Important Is It to Preserve the Evidence?

Steve Grundhoefer:

Yes. The scene work, I’ll start with because a lot of the crashes, the officers that are investigating this are not trained reconstructionists. They’re there just to fill out the report, make sure that people are safe, and taken care of health wise, and getting everything cleared off the road so they can open it up, but they don’t know what’s really critical when it comes to traffic and to figure out what happened in the crash.

Steve Grundhoefer:

So, a lot of times, I’ll get scene photographs that were taken, and the first photograph will be the license plate of the car because they want to identify that for their report. Then, they’ll take photos around the car where it’s at final rest, and you’re like, “All right, the crash was over down here 100 feet.” We don’t have a single photograph there.

Steve Grundhoefer:

So, you need to get out there and make sure you’ve documented the evidence. So, if it’s a new crash, I want to get out there within a day or two after I get the assignment, get out there as soon as possible, in case tire marks fade, gouges disappear. Sometimes, I’ve had roads to get repaved totally, and then even if you have photographs, they have no survey data, you can’t reestablish the evidence as well because you use sometimes like a dashed white line or a reflector here.

Steve Grundhoefer:

I can reestablish where that evidence was with that using some photographs, but the sooner you get out there, and can document all the evidence as soon as possible, all the tire marks, any gouges, fluid where it’s at, ruts that were created, then the more you have to do a better job reconstructing the crash. It’s same thing with the vehicle, like you said, the vehicles now have electronic data.

Steve Grundhoefer:

So, being able to get that vehicle before it’s destroyed, get the data that might be in the vehicle, get actual good pictures of the vehicle where the damage is what they call the contact damage was where, the two vehicles are physically in touch, you want to document that area really well.

Steve Grundhoefer:

The induced damage is crushed, and that’s caused by not necessarily direct contact, but because there’s so much deformation. It’s pulling other parts and displacing other parts, and so seeing the vehicles getting good documentation is vital to do a better job in reconstructing the traffic crash.

David Craig – Host:

I think, the people who are listening to this, that if nothing else, they learn from this. They should, if they’ve been in a catastrophic wreck, or someone’s been killed, or it’s a serious injury, they should contact a lawyer that knows what they’re doing as soon as possible. And they should be asking them, “Do you have a team that can get out to the scene and lock in this evidence and preserve this evidence, and are you planning on sending what we call preservation letters out to the defendants, so they know to preserve the vehicles, preserve the scene?”

David Craig – Host:

If your lawyer is hesitating and doesn’t know what you’re talking about, then you may want to consider interviewing a different lawyer because as you said it can affect the puzzle. If you don’t have all the pieces, you don’t know necessarily what the puzzle is. I see that all too often where they said, “Well, guys, it was the car at fault, or the semi is at fault. It’s clear. And so, we don’t need to do any of that.”

David Craig – Host:

Then, later, they find out there’s a defense or there’s something raised, or they blame somebody else. That evidence is long gone, and the ability to disprove something is gone. So, I hope people listening to this will at least ask their lawyers, “Hey, are you doing it,” and expect them to get the right team and hire the people. The clients don’t have to pay that upfront, and it comes out later.

David Craig – Host:

So, the lawyers should be investing in doing that, and I’ll give you one example of construction zones. I mean, I get every year wrecks in construction zones. People die in construction zones, and big rig semi trucks hit them, but construction zones change and are so dynamic that if you don’t get hired quickly, you’re really behind the eight ball.

Steve Grundhoefer:

Yeah, you want to make sure they got the appropriate signage and the cones and barricades where they’re supposed to be. And so, yes, you want to get out there, because right after the crash in two or three days, they may be moving down the road, and totally changed all the signage and everything. So, it is on those construction zones, it’s very vital to get out there as soon as possible.

David Craig – Host:

Yeah, and we’ll 3D scan the scene of the wreck in a construction zone, but we’ll also use a 3D scanner that go out, and actually run. We put them up there on the back of trucks, and they run them back and forth up through the lanes. So, you can actually follow the path of the vehicles and capture the road and the turns and all the signs. I mean, it’s just amazing what you can do if you get hired quick enough.

Steve Grundhoefer:

Yes, the scanning has really changed the industry for the amount of data you can collect and preserve very quickly.

David Craig – Host:

Yeah.

Steve Grundhoefer:

It does take enormous computers nowadays with all that data.

David Craig – Host:

It’s true.

Steve Grundhoefer:

Yes.

David Craig – Host:

So, let’s talk a little bit about, we alluded to it earlier, but a lot of vehicles, most new vehicles have data that can be extracted from the vehicles, the semi-tractor trailers and the cars. As more older vehicles are disappearing and getting replaced with newer ones, I’m seeing fewer and fewer wrecks that there isn’t some type of data. So, talk a little bit about that, how is the data stored? How do semis and cars have this stuff?

How Is Data Stored in Cars and Semis?

Steve Grundhoefer:

I’ll start with the cars because I think they were the first vehicles that started recording data, and that was the airbag module system. The airbag system is what records data on cars, that airbags are designed. So, it’s amazing the technology that goes into design because a typical severe crash lasts a tenth of a second. Just .1 seconds, and for an airbag to be effective, they have to be deployed within point .04 or .05 seconds.

Steve Grundhoefer:

So, the airbag system has to figure out how fast is this car seeing the onset of a crash? Is this a crash we need airbags? Does the driver have a seatbelt on? Where is the position of the seat? So, the technology on how fast they make these decisions and get airbags out was incredible.

Steve Grundhoefer:

One of the benefits is that, if it wakes up the airbag system, the brain of the airbag system, they call it the airbag control module does record data now, and it records typically. Used to be the old GM was the first manufacturer that they started recording in the late 90s, mid-90s, and you get five seconds of pre-crash data, which was vehicle speed, braking, if the brake was service brake on/off, and engine RPMs. You get that data for every second for five seconds of data.

Steve Grundhoefer:

Ford was the next one started coming in, and they started getting more and more data. So now, we’re up to, I’m not sure what percentage. It’s well over 90% of the cars manufactured in the US that have an airbag system. Federal law is now they have to record data if they’ve got an airbag system. You’ll get a GM or not GM, but Chrysler, they were one who started recording steering input as well and getting a tenth of a second of data.

Steve Grundhoefer:

So, that was the first data is the airbag system wakes up, where even then if it just wakes up the evaluate the crash, doesn’t have to deploy airbags. If it just wakes up, you’ll still get crashed data, and you not only get the speed.

David Craig – Host:

How do you get that data out? I mean, so this car crashes, and say the airbag goes off or that airbag system was woke up, I think people are like, “Well, how in the world do you find out what it says?”

How Do You Get the Data Out of a Car?

Steve Grundhoefer:

If you’re lucky and it’s not too badly damaged, the easiest way is under the electronic communication port under your steering wheel, normally, the DLC. You can go to that and plug into it with your computer. If you got power to the module through that system, you can download the data using it’s called the Bosch CDR software and system, and you can access the data.

Steve Grundhoefer:

If it’s too bad, if there’s too much electrical damage, you can go locate that airbag module, which is somewhere under the driver’s seat, under the passenger seat, or somewhere in-between the seats, either up under the dash or all the way back. They may be between the seats.

Steve Grundhoefer:

So, you locate the module, pull, do the download in the car. You’ve got cables, each module the manufacturer makes cables for certain cars. So, you connect your cable to the module, and the same software, and you can download the data that way.

David Craig – Host:

Nowadays, with cars, they have a lot, they have crash avoidance stuff. It’s amazing, mirrors light up, or if there’s somebody in the blind spots.  You’ve got a whole bunch more, people talk over the phone or they have bluetooth technology.

David Craig – Host:

So, I would assume, and I don’t know how far along we are. Is that information helpful? I mean, can you find out like if somebody’s swerving over the lanes, the cars vibrate, they do a variety of things? Is that information preserved at all?

Steve Grundhoefer:

Now, there’s this infotainment center data that you can get, which will give like turn signals and door opening, and all kinds of data. There’s additional data that’s not really accident reconstruction related that you get as well. It’s amazing, the data, that the infotainment, anything if you’re using the GPS to following a GPS.

Steve Grundhoefer:

So, there is tremendous amount of data that you can get from a car using those systems to download. It gets into a proprietary, I guess, in the criminal case, you can use all that, you’ll get that data. Then, there’s accident reconstruction which consists of a lot of data that might be protected, but there is data there.

David Craig – Host:

So, I mean, obviously, I do a lot of semi-tractor trailer cases throughout the country, and certainly, the amount of data that’s available now in those semi-tractors and the trailers is a lot more than when I first started. So, talk a little bit about what kind of data is there and how do you extract that.

What Kind of Data Is Available After a Crash and How To Extract That?

Steve Grundhoefer:

Yes, their initial data was usually coming from the ECM data that records hard brake event data, is what they call it. On the semi, the airbag system is not involved in this. It’s the engine control module on a semi that records data. So, a lot of the newer semis are set up to record what they call a hard brake sudden deceleration event they each call it something different. It records, if the level of braking reaches a certain level, usually seven to nine feet or miles per hour per second deceleration, somewhere in that range.

Steve Grundhoefer:

If the truck driver applies the brakes and decelerates at that rate, it will record that event up 60 seconds of data like a one second. Then, 15 seconds after the event, it records data. So, that was the initial data that we were getting from a lot of semis. Of course, the ABS system also provided some data. You usually didn’t get as much data out of ABS, unless there was a fault or some failure in the crash, and you’d get spot speeds at that point.

Steve Grundhoefer:

Now, if this keeps evolving, it’s hard to even keep up with what all is being recorded by semis now with the crash avoidance systems and cameras that capture video and crash avoidance and speeds that you can get from the crash avoidance. The ABS now, is also starting to record more and more data from crash events. You can send the information in now, which we didn’t know in the past.

Steve Grundhoefer:

If you downloaded the data off ABS, you now can send that in. Now, unfortunately, it’s taking a year to get the data back. They actually had the technology to interpret that and give you steering and braking and everything. So, that’s becoming more prevalent. So, the technology, it just keeps evolving.

Steve Grundhoefer:

Now, you see more and more cameras be employed by truck drivers and systems, they drive CAM systems. I mean, they’ll show what the driver is seeing forward. Sometimes, what they’re seeing in the back and what the drivers doing inside the cab is being recorded in these incidents.

David Craig – Host:

Yeah, in other commercial motor vehicles, like buses and IFCC videos most buses will have some type of video stuff, and for semis, it is more and more common to see cameras looking outward, can you see, I’m looking back at the driver as well. We’ve got cases where we see both.

David Craig – Host:

I know that preserving evidence sometimes these semis are not totaled. They can kill somebody and still drive away from the scene. What happens when they drive away, and they have other brakes? Does the semi, I know the answer, but the semis will… Can they record over that?

Steve Grundhoefer:

Certainly, yes. The hard brakes, they usually can store at most two hard brake events, and if the driver is going down the road and has another incident where he hits the brakes hard enough to record, it will overwrite that prior event. So yes, if that data is not recorded or downloaded immediately, and if they allow the truck to continue to drive at that, it can be easily lost pretty quickly.

David Craig – Host:

That’s another reason why we send out these preservation letters that say, “Please don’t move the vehicle.” I mean, because oftentimes, the police sometimes, if it’s a fatality or bad wreck, they may impound the vehicle temporarily.

Steve Grundhoefer:

Yes.

David Craig – Host:

Now, unfortunately, what they’re doing usually is just like a level one inspection, they’re not doing anything in a lot of detail. Sometimes, they don’t even have the equipment to download anything, but you send these preservation letters out. So, you try to get somebody like yourself in there, and do the downloads before they drive that vehicle again and have another hard stopper, intentionally or unintentionally.

Steve Grundhoefer:

Yes.

David Craig – Host:

They’re not easy. I’ve seen you and your dad, literally have to tear up a semi-tractor trailer, or tractor, to try to get to that data. So, how do you get the data out of these semis?

How to Get the Data Out of Semis?

Steve Grundhoefer:

Like the other ones, you’re fortunate if it’s not badly damaged, you can plug it under the dash again to that and download the data. But, unfortunately, some of these are pretty severe crashes. You actually, pull modules and have to ship them off possibly to get them downloaded.

Steve Grundhoefer:

I know, like Detroit Diesel, some of them have, a module on the engine you have to remove, you got another one that the speedometer is the instrument that you have to pull out and send in. Then, there’s the module in the dash itself that’s the hard one to get to that really which has the best data. So, you usually, get your hands dirty and usually have a lot of cuts and bleeding when I’m done.

David Craig – Host:

I know that, when we do these, we hire a reconstructionist like yourself that oversees and gets all that information, but then another part of what we do is, you’ll often suggest, or I’ll volunteer to have a mechanic there as well because again, you get one shot to look at these vehicles. So, I know recently, we had you and a mechanic, and I’ve used a mechanic and reconstructionist multiple times, where they’re looking at it, are the brakes working properly? Is the engine running properly? Different types of things like is the accelerator sticking? So, I mean, I guess you as reconstructionist, you work with other people sometimes, to try to figure these things out.

Steve Grundhoefer:

Yes, I’ve got a mechanic I work with quite often. He’s a regular mechanic for a lot of his life, repairing passenger cars, but then he moved into running a diesel shop and repairing heavy vehicles. I consult with him quite a bit and use him on cases where I think there is a mechanical issue with the truck or the car, tractor or trailer, we need to look at, and thoroughly evaluate.

Steve Grundhoefer:

So, because that’s the one thing, I’m an engineer. If I could go back to high school, I probably would have taken more automobile mechanic classes because I was doing all the math and physics, not the mechanical part.

David Craig – Host:

I know the guy that you like to use Gary. Actually, he’s been a guest on the podcast as well and talks from his perspective how things are different, and what he looks for, what he does. But yeah, I mean, it’s a team effort. I mean, depending on what case it is, sometimes I have investigators going out trying to talk witnesses and get witness statements that help fill-in-the-blank, sometimes we talk to the police, and you’ve got reconstructionist, and you’ve got mechanics, and phone downloads has become a big part, there’s download information from phones.

Steve Grundhoefer:

Yes.

David Craig – Host:

There’s a lot more there.

Steve Grundhoefer:

Yes, it’s never ending.

David Craig – Host:

One of the things I want to talk about today is stopping distances. I think about semi-tractor trailers and cars. I sometimes see people driving on the highways, and they cut off semis. I don’t think they realize that these semis just can’t stop on a dime. I was hoping maybe, you could educate people a little bit about stopping distances on semis and cars, and I guess first of all, what factors are involved in determining how quickly can a vehicle stop?

What Factors Are Involved in Determining How Quickly a Vehicle Can Stop?

Steve Grundhoefer:

Yes. There is a big difference between the semi-tractor, a passenger car, and motorcycles, and other unique vehicle when you’re looking at stopping distances. The passenger car is probably, going to be the easiest as far as using the hydraulic brakes, and you don’t get any real delay in the brake system when you apply the brakes. We’ve got pretty good established braking charts and stopping distances for cars.

Steve Grundhoefer:

For semis, they are heavier vehicle, and a lot of people think it’s the weight alone that causes a greater stopping distance. It does go into play of how much force and work you have to do to stop that vehicle, but the brake systems are designed to handle that work and be able to handle the heat that’s generated. Probably, the biggest thing that causes bigger stopping distance on the semi is two things. The tire composition on the truck is a harder rubber. They make that because trucks, they carry such heavy loads. They need to get about 300,000 miles out of each set of tires.

Steve Grundhoefer:

So, they got a heavier tire and harder rubber that doesn’t generate as good of friction and traction as a car tire. So, that reduces their drag factor capabilities, and the air brake system, it’s great for semis, but it does have air brake lags in it. So, those two things combined, generally, make the trucks at least one and a half almost two times greater stopping distance than what you have with the passenger car.

Steve Grundhoefer:

So, yes, you need to allow those truck drivers space. You can’t cut right in front of them because they can’t stop as quickly as you, and they need to maintain the proper following distance for the same reason because if the car stops suddenly, they can’t match that car stopping. So, the stopping distances are quite different.

David Craig – Host:

So, I mean, I think a lot of people probably think if a semi is fully loaded and is carrying his maximum weight that it’s allowed to, then that it is harder to stop. It’s going to take longer to stop than a semi that is running empty, and that’s not necessarily true, is it?

Steve Grundhoefer:

No, it’s actually the opposite. It’s actually, probably, best to have a load in there and weight on the tires because that’s what you’re generating friction between the way you stop the vehicle that momentum is keeping it going, its weight and velocity in the one direction to stop it, you got to put a force in the other direction which is generated by the friction that can be generated between the tire, and the roadway.

Steve Grundhoefer:

The more weight, the more friction that can be and resistance force to stop that momentum. So, it actually helps to have weight in trucks and the less weight, then the less resistance you get from the friction. So, to a point, I guess you don’t want to overload trucks, because then the components, if they’re sustained braking, they overheat and start losing some of their function or their ability to stop. That’s yes, it’s actually better to have a loaded truck than to not have a load in it.

David Craig – Host:

Again, to I make sure I understand. So, one of the reasons that a car can stop quicker than a semi is that they have different types of brakes. Is that right?

Steve Grundhoefer:

The tire composition, I think is the biggest component with the car passenger tire just grips the road better. That’s what you’re looking, that friction that develops between the road surface and the tire itself. So, they generate on an asphalt road, or concrete road, you can get points .7 to .8 they call it Gs, or friction factor, the best probably, gets about .5 to .6. So, that’s one of the big factors.

Steve Grundhoefer:

Then, that airbrake lag time where you don’t see that in a car, you apply the brakes, you pretty much get quick response. We’re getting the air to all the systems and getting everything functioning. There’s usually, a third of a second to half second air brake lag, where you’re starting to apply the brakes, but nothing’s really happening until it gets that force generated.

David Craig – Host:

Some people may have heard the word drag factor or whatever, but certainly, the road surface has an impact on the stopping distance as well. I would assume that if the roads wet, if it’s gravel, or if it’s ice and snow. I mean, talk a little bit about the road surface, how that affects the stopping distance.

How Does the Road Surface Affect the Stopping Distance?

Steve Grundhoefer:

Yes, it is that friction that you’re wanting to develop between the tire and the road versus having a dry asphalt or concrete with fresh new asphalt, that’s where you probably get your best friction where the tire can generate that force to stop the forward momentum of the vehicle. If you get into a rock, you don’t have that. The rocks will slide on each other. You don’t get near the friction and resistance that you would on a hard surface like asphalt or concrete.

Steve Grundhoefer:

When you start throwing a wet pavement in, you’re taking away some of that friction that can develop, and so your drag factors go down. That’s the longer stopping distance on a wet pavement, and substantially, when it comes to ice or snow, you just start developing friction between the slides. The tire will slide on that surface and have very little force to stop the forward momentum, the weight and speed of the vehicle.

David Craig – Host:

Every state has a commercial driver’s license manual that truck drivers have to study and pass to get their CDL, and in that, under most states, CDL manual, it will say that a semi-tractor trailer, if it’s on a wet pavement, it should decrease the speed by third. If they’re driving on packed snow, they should decrease their speed by 50%, and if they’re driving on ice, they need to get off at the first safe opportunity. I assume that the reason they’re decreasing speed is helping the stopping distance on those bad surfaces.

Steve Grundhoefer:

Yes, I mean, with the weight of the semi, the momentum they have is tremendous because you’re looking at 60,000, 70,000 up to 80,000 pounds, if it’s going 60 miles an hour, it’s momentum is the weight times the speed. So, you got that much momentum going. Where our passenger car might be 5,000 pounds at 60 miles. If you do the math, it’s probably 16 times the momentum or I didn’t do the math after that, you get a greater momentum with a semi.

Steve Grundhoefer:

So, trying to get that stopped is going to take, if you have reduced friction, it’s going to take substantially greater distance. You’re not reducing that momentum and that’s really the key. What’s really critical is what causes severe crashes is the momentum, the speed, and the weight is what is critical in a crash. They can do more damage and end up with fatalities, the greater the momentum.

David Craig – Host:

I think it’s helpful for people, you provided me with a chart, and we’ll put that up for folks to look at. Maybe, you can go over it, the stopping distances for large trucks. So, the folks will be able to see that. Can you walk us through that chart and what it means?

Steve Grundhoefer:

Yes, that one shows various speeds, what the stopping distance is for a semi versus a car. They start at 20 miles an hour. Part of the stopping distance is the person in the vehicle. They go out the perception distance that’s on the chart, which is on this instance, they use 1.75 seconds for the person to perceive that they need to apply the brakes.

Steve Grundhoefer:

Then, there’s another distance that they’ve got as reaction distance, which is the physical movement of their foot from the accelerator pedal to the brake pedal. So, that’s a three-quarters of a second. So, those two add up to the two and a half seconds, that the vehicle is not slowing at all. It’s continuing at the same speed.

Steve Grundhoefer:

Then, they have the braking, once the brakes are applied, here’s the distance from 20 miles an hour, it takes a semi to stop, and 20 miles an hour, it would take a passenger car to stop. That’s the slowest speed, and it shows on that chart 103 feet for the semi from 20 miles an hour and 92 feet for the passenger car.

Steve Grundhoefer:

So, it’s not that big a difference with those speeds, but if you start looking up higher speeds, you get up to the interstate 70 mile an hour speed, and you put in there, the distance for the semi goes all the way up to the braking part goes to 490 feet, where the passenger cars 233 feet. The other two stay the same, so you get a tremendous difference in the semi. That’s a combination of having the momentum, trying to stop the vehicle and the airbrake lag time. So, a semi just with the higher speeds takes a greater distance than the passenger car.

David Craig – Host:

I think that the chart shows, from 20 miles per hour, 30 miles to 55 and 70, and you know what people will notice on that is what we call perception reaction time. It’s pretty much going to be the same for the semi driver and the car driver. I mean, they’re going to take the time to perceive that I need to stop.

David Craig – Host:

Then, it’s going to take time to get your foot down the brake, and actually take some steps to do something, but then, you can see, like you said, the faster you’re going, then the harder it is for them to stop that semi.

Steve Grundhoefer:

Yes.

David Craig – Host:

That’s something you need to be aware of, if you’re sharing the roads with semis, which nowadays, we’re sharing roads with lots of semis.

Steve Grundhoefer:

Yes.

David Craig – Host:

I think people need to be aware of that. So, anything else on stopping distance that you think would be helpful for just the average person to know when they’re out there traveling on the highways?

Steve Grundhoefer:

Yeah, one we didn’t really talk about vehicles and motorcycles because that’s a one, it’s a unique one, because you have two separate braking systems on the motorcycle, where the driver, it’s really the skill of the operator comes into big play on that, and because it’s typical, you’ve got a rear brake you apply with your foot, and then you got a handbrake, which controls the front wheel.

Steve Grundhoefer:

So, they’re two separate systems, and the skill of the rider really, comes into play because if you’re in a crash on a motorcycle, you don’t want to jam on the front brake and lock the front wheel because then, you lose all control. The vehicle will end up falling over because you’ve lost your stability. So, a skilled rider really has to know how hard to apply the front brake and the rear brake combined to stop. So, that’s totally different stopping system and it’s very skilled oriented stopping.

David Craig – Host:

Just out of curiosity, is there data in a motorcycle that you can download?

Is There Data in a Motorcycle That Can Be Downloaded?

Steve Grundhoefer:

They are starting to look. I know Kawasaki is now starting to put a data recorder. I think they’re the only one I’m aware of yet, maybe, some of the other high-end. We haven’t heard as much yet. I think it’s coming because motorcycle crashes are about the hardest to do because the old traditional math, you use momentum and energy don’t really apply when you have a 600-pound motorcycle crashing into a 5,000-pound car or even a larger vehicle. The momentums are so much different. The motorcycle has no momentum.

Steve Grundhoefer:

So, it makes the old traditional math hard. So, if they could get the recording, electronic recording, in the motorcycles, I think that would be a tremendous benefit to the accident reconstruction part of it.

David Craig – Host:

Along those lines, sometimes even when you have all this data that’s available in vehicles, I still get cases occasionally where there is no data. For example, I had a school bus that hit a pedestrian and they had not activated, it was disconnected. So, there was no data in the ECM. I had a box truck that the company had chosen not to activate their system.

David Craig – Host:

So, there was no data. We had reconstructionists look at both of those, and there was no data in either one of those vehicles. So, we had to come back and try to figure out the speed of those vehicles. I know you’ve done that as well, and nowadays, we see security cameras all over the place.

David Craig – Host:

There was this in the bus case, there was a security camera that will look back towards the kids and the bus, and we knew the route. So, we were actually able to get out to the scene quick enough that we could go by the shadows.

Steve Grundhoefer:

That was my case.

David Craig – Host:

We recreated that, right? So, we could determine the speed by something that was really unique, because there was no download available on the bus because it hadn’t been activated. We used shadows to show and determine speed, and I’ve had other ones where we’ve used security videos to look at things, major things. Talk a little bit about that. I think you had a case where you’ve had to do that, or you’ve had multiple that you did work on the bus case, and you’ve worked on other cases.

Steve Grundhoefer:

Yes, like you said, the security cameras are everywhere anymore. And I had a case, a really interesting one, probably about a year ago. It was three vehicles that were involved approaching on, two of them were on the one street approaching each other. Another one coming in from a different direction. We got videos from three different angles of the vehicles approaching the intersection. One of them caught all three vehicles approaching.

Steve Grundhoefer:

We were able to capture and get that video and break it in to figure out what the frame, how many frames it is per second. In the video, break it into a frame by frame, and then, when I go out there, with my survey equipment, I located that camera and I shot the location of the camera, and then objects there along the road, so I can figure out where the front of this truck passed between the line, between the camera, and the power pole that’s behind it.

Steve Grundhoefer:

Then, another 80-feet down the road, 100 feet, the front camera of the truck from the truck passes between the camera and this canopy post and knowing he’s driving down this lane of the roadway, I know the distance he traveled from where the front of the truck passes this line to this at distance. We know, it’s so many frames per second of video. So, you count how many frames, and you have distance and time, you can come up with the speed that he traveled during that distance.

Steve Grundhoefer:

So, we had this is on that case where we had both the ECM download, we actually got the download, and from all three vehicles, we got data, and we had camera views, so we could step by step, they had matched up perfectly with the data from the downloads. This one was particularly of interest because there was a vehicle that came, its nose came out from behind the corner of a building and we were trying to evaluate was there any delayed response on the one driver’s reacting to it, and you can start step by step, say, “Alright, right here is where the nose of that car first become visible, and when did we start seeing him respond?” So, it was very powerful tool.

David Craig – Host:

I know you sent me pictures. Was it the truck with the black back on? Or the white truck pulling the black?

Steve Grundhoefer:

Yes.

David Craig – Host:

And so, you were measuring that as it went by the different things.

Steve Grundhoefer:

Yes, it was the nose of the truck. It was a dump truck that was coming into view. You could see it passed by that power pole, and then a little bit further down around. So, we knew his speed from that video, and it did compare almost identical to the speed that was obtained from the download.

David Craig – Host:

I think that it is fascinating. I think that’s why, again, preserving evidence quickly, so you can have those measurements look at that. In the case, on the box truck, it didn’t have anything, but it drove by a car lot. So, if the car lot captured it, so we were able to break it down frame by frame and see that, but sometimes, security cameras they don’t keep that stuff very long. So, if you don’t get it, you’re out of luck, and there’s no download.

Steve Grundhoefer:

Yeah, I had a case recently where the driver was driving without headlights on. He just had his running lights at night, and we got the security camera on that case. You can tell other cars come by and they have their lights fully on, and he drives by and it’s like his lights aren’t on. They have no other way of reconstructing what happened. We got that security camera. It was a pedestrian hit and run. We figured he didn’t have his lights on. Sure enough, he went around the corner and went through the security camera, and he did not have lights on.

David Craig – Host:

Are you seeing more security cameras like whether its DoorDash or even on pole barns out in the middle of nowhere? I mean, are you seeing more of that?

Steve Grundhoefer:

Yes, it’s nearly almost every crash where that’s one of the first things I look around is, is there any security cameras here? Houses or businesses, they just seem to be everywhere now. So, yes, I’m seeing more and more of that.

David Craig – Host:

Anything else? Steve, I appreciate you taking the time to talk to us on this podcast. Anything else that you think ordinary folks that are out there that unfortunately have a loved one killed in a serious wreck, or had themselves or someone else seriously injured? Anything else that you could think of that they need to know from a reconstructionist’s perspective?

Steve Grundhoefer:

Yes. Like you said, you do want to get out there and document all this stuff as soon as possible because that’s how you reconstruct, and the more pieces you have to the puzzle, the more I can help and determine what happened and what the speeds were. Like you said, they have to get a good attorney that knows to preserve, get this stuff preserved with all the electronics and cars, there’s a good chance that the newer cars will have data, you let that be destroyed. That evidence, it’s gone. It can’t be got back. Like we talked about the scene. So, the sooner you get the evidence, the more you document the evidence, the more we can help.

David Craig – Host:

I appreciate it. I know that the first question clients asked me is, why did this happen? How did this happen? And like you said, the sooner I get hired, and I put a team together of people like yourself, or reconstructionists, and mechanics, and private investigators, to look for security cameras, look for video cameras, the easier it is for me to answer that question, and that’s the question they have.

Steve Grundhoefer:

Yes.

David Craig – Host:

So, well, thanks again. I appreciate it, and this will end this episode of After the Crash.

Steve Grundhoefer:

Thank you.