Steven Gacin & Bob Salemme

Steven Gacin

Q. Tell us about what led you to be an engineer. Was there a moment or a person who inspired you to pursue this career?

SG: There was no one moment, but it started at a very young age. Like every developing engineer, I was fascinated with how things worked and I tinkered, and broke, many household items in order to understand exactly how they ticked and why. To calm my idle hands and mind, my father, who was a carpenter, would frequently take me with him on build activities. This only fueled my passion for creating, shaping, forming with meticulous attention to detail and ultimately becoming a “maker.” The STEAM (science, technology, engineering, art and math) programs and the rich and vibrant creative culture that I grew up with in Providence, Rhode Island nurtured my passion for art and design. Combining my love of tinkering, my fascination with creating, and my passion for the arts, science and technology, it’s no wonder that I ultimately became a design engineer!

BS: My high school counselor recommended I give engineering a shot because I did well in math and physics classes. During my first year of college, I was still undecided about what major I wanted to pursue. My academic advisor recommended that I take the Strong Interest Inventory. You answer 300 questions, and based on your likes and dislikes, the results tell you “here are the top ten careers you may enjoy the day-to-day grind of.” Mechanical engineer was third, after college professor and photographer, so I decided to go for it. It has been a tremendously satisfying journey so far.

Q. Your jobs are pretty cool. Which came first – a love of cars or a love of engineering?

SG: My love of engineering came first, and then came my love of cars. Vehicles are a great feat of engineering, the effort and complexity required to make a vehicle and to do it well takes a lot of time. The complexity of design and engineering is especially true for vehicles designed for the consumer market, where you are not just making a metal box with tires to get from point A to point B.

So much needs to be considered to make a vehicle catered to the customer’s needs and satisfaction, from the meticulous design of the transmission, suspension and programming systems for optimal performance on the road, to the extensive crash testing to provide the safest cabin space, and that small seemingly insignificant radius on the center console where your thumb may rest! To create a truly well-crafted vehicle, there is no one field of engineering to get you there. We need individuals from all backgrounds — mechanical, electrical, process, industrial and human factors engineers — to create something that consumers will love. It’s a great way to learn about methods and detail outside your field.

BS: My love for engineering came first, too. I always really enjoyed the lab portions of my engineering classes. There is something really fun about finding different ways to solve open-ended problems. When I started at Honda, my car knowledge was limited – I knew they had four wheels and an engine. As soon as I started the job, I bought myself a car with a manual transmission. I purposely bought a hoopty with the goal of learning how to fix it as it broke down. Honda also provided extensive training programs which enabled me to gain the necessary experience to confidently do the job of a crash test engineer.

Bob Salemme


Q. Steven, what is it about vehicle and occupant safety that you find most interesting? Most challenging?

SG: What I find most interesting about occupant safety is the challenge and complexity of it all. To develop a vehicle that will protect people in a worst-case scenario crash event is no easy feat, and there’s a lot to consider. Every aspect of every vehicle component, from its material selection, to its structure, shape, breaking strength and position, plays a role in a vehicle’s final crash performance. We can’t prevent all crashes from happening… yet. So, we’re tasked with trying to reduce the overall impact to the people in the vehicle, which can be generally done by slowing down the crash event.

How do we do this? First, we must understand that every crash event has three main phenomena:

  • The vehicle crashing into a moving or stationary object
  • The occupant crashing into the vehicle interior once the car’s motion has been affected
  • The occupant’s internal organs crashing into their own skeletal frame.

Injury generally increases as time to decelerate decreases. The faster a vehicle stops during a crash event, the higher the probability for injury. But, if you can increase the time or duration of each phenomenon, you can mitigate the severity of the impact. The longer it takes the vehicle to come to a full the stop, the more delay we see in the speed of impact of the person against the vehicle interior. That allows for the deployment and functionality of the airbag system. The airbag system then reduces the speed of impact of the person’s internal organs against their own skeletal frame, thus reducing injury. Each of these steps adds time to the event; you can think of it like the dream states in the movie Inception. In each of the three main crash phenomenon or “dream states,” there is a small compounding time difference (milliseconds or so) which ultimately accounts for a major difference in the crash that can positively or negatively impact the overall event, depending on how you design and control each part.

Every aspect of every vehicle component, from its material selection, to its structure, shape, breaking strength and position, plays a role in a vehicle’s final crash performance.

– Steven Gacin

Q. Bob, as a front crash engineer for many of Honda’s top-selling vehicles (Accord, Crosstour, Pilot, Odyssey), how do you collaborate with teams across the company to improve vehicle safety?

BS: With over 30,000 parts on the car, there are many different groups involved in bringing a final product to customers. Each group is focused on a different aspect– durability, dynamic performance, crash testing, and fuel economy just to name a few. Each group has priorities which have the potential to negatively impact other groups. For example, if the vehicle was built like a tank, passing safety targets may be easy, but the fuel economy folks may have trouble meeting their targets. The “trick” is finding a balanced system that satisfies all the various groups.

Steven Gacin


Q. Steven, what engineering principle(s) do you apply most to your work on steering wheel feasibility and restraint systems?

SG: The engineering principles I use most generally are manufacturing, testability, integrity, integration, ethics, and design/form.

Manufacturing: The steering wheel or restraint system should be easy and cost effective to create.

Replication: We need to be able to replicate the results and identify those items that can remain constant and isolate others – consistently.

Integrity: The steering wheel or restraint system should have structural integrity. Material selection and part structure are carefully considered.

Integration: The steering wheel or restraint system should have clear “one-way” integration into the system. It cannot be mis-installed, misaligned or misused.

Ethics: The parts should be developed with the best interest of the customer and the company in mind. NO SHORTCUTS.

Design/Form: The parts should be designed for a purpose and it’s GOTTA look good!

Q. Bob, a big part of engineering involves modeling & simulation (M&S) and test & evaluation (T&E). What M&S and T&E processes and technologies does Honda use in its vehicle safety programs?

BS: Prior to crashing any of the cars, there is extensive modeling done to simulate crash tests. We use various software packages to create, run, and post-process the models.

On the test side, during development, we run many component tests & front crash simulator tests (sled tests). Once we have demonstrated that the restraint system has prospect on the sled, we can then run the full-scale crash test. Once the full-scale crash test has been run, the simulation model can be validated. Did the simulation match the test? Why? Why not? How does the simulation need to be tweaked to closer match the physical test?

Once the simulation has been validated, we can confidently use the model to predict the effect of various changes.

Oftentimes, we get emails from people who have been in terrible car accidents. They will send us pictures and thank us for building a car that was safe enough for their family to walk away from after an accident. Moments like these really cement the realization that the work I am doing is helping to save lives.

– Bob Salemme

Q. How does a front crash simulator work? What capabilities does it have that would surprise or impress people?

BS: The front crash simulator uses a hydraulic piston to push a vehicle rearward on a track. As the vehicle moves rearward, the occupants engage the restraints (seatbelts & airbags). Here’s a good video link to demonstrate.

Front crash simulators are an important tool in a crash test engineer’s arsenal. They are a cost-effective way to try many different restraint tuning knobs before going to the full-scale crash test. A sled test may cost just a few thousand dollars whereas early prototype full-scale crashes can sometimes cost up to a million dollars.

Q. What’s it like to know that the work you do every day helps save lives?

BS: Oftentimes, we get emails from people who have been in terrible car accidents. They will send us pictures and thank us for building a car that was safe enough for their family to walk away from after an accident. Moments like these really cement the realization that the work I am doing is helping to save lives.

SG: It is one of the most rewarding experiences. When you work on a vehicle’s development for years, with the need to meet deadlines, cost and weight requirements, industry requirements, government requirements and consumer market trends, it’s easy to get enveloped in the process and lose sight of the underlying reason why you’re doing what you’re doing. But, when you receive that letter from a family you’ve never met, who has just been in an awful accident but walked away alive and with few or no injuries, it helps put things back in perspective and further justify what I do, and who I do it for.

Steven Gacin and Bob Salemme contributed to this Q&A in their personal capacity. The views and opinions expressed are their own, and do not necessarily represent the views of Honda R&D.