When Ed Welburn retires from his post as General Motors' global design chief this July, he'll be leaving behind a 44-year legacy that cuts right through the most turbulent era in GM's long history. There was the culling of the Pontiac, Oldsmobile, and Saturn brands; bankruptcy and a federal bailout; the 1973 energy crisis that flipped the American auto industry upside down and heralded the rise of fierce Japanese competition.

Basically, Welburn had an interesting career (to put it mildly). But his successor — 33-year GM vet Michael Simcoe — is likely in for an even more interesting run. Automakers of all sizes have started tripping over themselves in a bid to reinvent their businesses as quickly as possible, preparing for a world where we live in carless megacities interconnected by vehicles that have no drivers. Gasoline has started giving way to battery packs. Silicon Valley versus Detroit has overshadowed GM versus Ford. The challenges are very different — and arguably, more hostile to legacy automakers like GM — than the ones Welburn dealt with at the drafting table inside Buick's design studio circa 1973.

I had a brief chat with Welburn recently to talk about his retirement, and he agreed that car design is about to shift dramatically — but he argues that the self-driving revolution is still a ways off. "Everyone's talking about autonomous vehicles, and it's still a few years away. There's a lot of work to do between now and then," he says. "It depends on what level of autonomous technology the vehicle has, but the driver of the car will bring about a very different way of thinking about an automobile. That change will then have an influence on other vehicles that may not be autonomous at all."

He also thinks that Simcoe is well positioned to take those challenges on. Of course he does; Simcoe almost certainly wouldn't have been chosen without Welburn's full blessing. But in the process of praising him, Welburn also makes the case to me for why they promoted internally rather than looking outside General Motors' studios. "The advantage he has is that he knows the people. He's been a part of GM Design his entire career, and a part of the leadership team in Design for I guess a decade now," he says. "I've worked very closely with him in the past few years, so he knows the team. He knows the organization. He knows the leaders of the company, they know him. He knows our engineering partners, which is a huge advantage, and that should help him."

"That relationship with engineering is extremely important, and keeping that relationship intact, you know, it's not easy," he continues. "They're very different people — engineers are very different from designers. But that collaboration is what really brings winning products."

But even though he asserts that working well with engineering is critical, Welburn doesn't believe that GM's technology (or any automaker's technology) is the great differentiator — even in the age of autonomy and the connected car. "At the end of the day, no company is going to have a huge technology advantage over everyone else for long. They will for a while, but not for long. Design will still be the great differentiator in the marketplace," he says. (I'd be willing to bet there are a few technologists inside GM who don't see eye-to-eye with him on that.)

He cites the Buick Riviera, the Oldsmobile Cutlass Supreme, and the Oldsmobile Aerotech — which is still an incredible car by modern standards — as some of his favorite design projects in the course of his four decades at the company. ("It's a personal luxury car that's got a lot of flair, which is really cool; I like very sculptural designs," he says of the Riviera.)

But those are all relatively old cars; techniques and tools have changed drastically for designers in recent years, and when I bring it up, I can hear the passion build in Welburn's voice. "Back in the ’30s, there was an incredible level of detail in a vehicle. And that gradually went away when the cost of having craftsmen hand-carve and shape things became too costly," he says. "But in more recent years, technology has allowed us to bring back, in a very contemporary way, a level of detail and refinement in our cars that we haven't had since the 1930s. It's technology that has brought it back — when you look at the surfaces, the fabric, the textures, the finishes in the interior, the attention to details in our lamps. Our lamps are no longer just a big bulb — you know, you open up a cardboard box, take the light out of the box, and stick it in the clay and you're done. The design of a headlamp or a taillamp is an incredible project, with layers of detailing that is pretty spectacular."

Lamps! His hyper-specific form of enthusiasm is a little contagious. Welburn isn't just excited about lamps; he manages to get me excited about lamps.

As our chat wraps up, I mention the Buick Avista, the gorgeous concept coupe that some people (myself included) thought won NAIAS in January. What sucks is that — like far too many beautiful concept cars — the Avista doesn't seem to be in the production plan, and I was desperate to get Welburn's take on it. "When we developed [the Avista], naturally it was not in the plan for production," he insists. "It was really a labor of love within the Buick studio to create a vehicle, a vision of what's possible for the brand, a vision of the evolution of the design language of the brand — the grille shape, the lamp shapes, the body side, the interior — all those elements came together in really this labor of love in the studio to express the future face of Buick design. And they did it in a very well-executed way. So if in fact there's a possibility of going into production, you could do that. It has been very valuable for the studio team, and every production vehicle that is under development in the Buick studio has been impacted by that car."

I want to buy his suggestion that future Buicks will have the Avista's styling elements, but as a longtime car nerd, I also know that reality can cast a harsh light on an auto designer's fantasies. We'll see; Welburn says that the last cars with his direct influence will probably come to market in a couple years' time.

And does he have any regrets? Anything he'd design differently? "They were all perfect. I'm only kidding!" he chuckles. "But seriously, I really feel good about the work that the team has done in my tenure. I feel very good about it. I guess if I searched through, I'd find some difficulties here and there where you'd like to make an adjustment in a design. But for the most part I feel good about it."

It's worth noting that Welburn did not design the Pontiac Aztek.