Thomas Dingus plumbs the fascinating and frustrating depths of human behavior, trying to save lives.

For a quarter century, Dingus has led the Virginia Tech Transportation Institute, which works with car companies, federal agencies and field researchers to understand the forces shaping America’s roads and more. They study truckers and seniors, new car technology in Texas, and Uber users in Washington, D.C. One researcher hid himself in a “seat suit” so the van he was driving looked like no one was behind the wheel, a ruse to gauge reactions.

Dingus, who recently announced he will step down from leading the institute, spoke to The Washington Post about teenage drivers, Tesla deaths and decades spent trying to understand what we do wrong, and right, on the road. The interview was lightly edited for length and clarity.

Q: How has the commute changed in America during the past 25 years, and how do you think it will it change in the next 25?

A: In some ways it hasn’t changed much and in some ways it’s changed quite a bit. One thing the pandemic has taught us is that it can change pretty drastically depending on current events. The pandemic was very interesting from a traffic safety perspective, because the miles traveled were down pretty substantially and still haven’t recovered fully, but the fatality rate went up a lot. … Speeds were much higher, probably because there is less traffic and probably because there was less enforcement. That’s been an interesting experiment in and of itself.

Over 25 years, traffic volume has generally increased, not drastically, but somewhat. That’s sometimes good from a safety perspective, because if you have traffic then traffic is not moving as fast, particularly on something like interstates. And so the fatality rate goes down. Of course it’s frustrating for everybody, wastes a lot of fuel, that kind of thing, and so that’s not good.

A big change has been the emergence of active safety systems. Those are things like lane departure warning and blind spot warning and forward collision warning, and now more automated features, like automated braking. It’s rolling out on new models and will eventually be in all of the fleet. That’s going to be a big plus in terms of crash reduction.

Passive safety systems like air bags and other restraints also have advanced. Side curtain air bags have saved a lot of lives. A modern high-end car has up to 11 air bags now, whereas 25 years ago it was one at most. There are a lot of reasons to be optimistic from a safety perspective. The evolution of automation and electrics, car share, ride share, will continue and that will have a variety of positive impacts. We’re just really starting to see the beginnings of that.

Q: The Governors Highway Safety Association released new data on Thursday projecting 6,721 pedestrian deaths in 2020, up about 5 percent from the previous year. But given the sharp drop-off in driving during the pandemic, the association said the pedestrian fatality rate jumped an unprecedented 20 percent, from 1.9 deaths for every billion miles traveled by vehicles in 2019 to 2.3 deaths by that measure in 2020. What is going on?

A: Part of it is pandemic related, certainly increase in speeds and increase in alcohol. Distraction is a little more tricky, but I’m certain that, in general, there were increases in and distraction as well. We did a study a few years ago that really showed that there is a serious distracted pedestrian problem, due to the increasing use of handheld devices and things like that. We did a study in Northern Virginia — you may remember the seat study. We were really trying to figure out how best for autonomous vehicles to communicate with other road users, like cyclists and pedestrians and other vehicles. But one of the major findings was that for pedestrians stepping off the curb, only something on the order of 22 percent even looked at the vehicle at all. … That was pretty shocking to us.

We have a distracted pedestrian epidemic. The trend was there pre-pandemic, and the other pandemic factors made it worse.

Q: Advocates for pedestrians and bicyclists often reject the notion that distractions on their part are the central problem here, saying the carelessness of motorists driving two-ton deadly weapons is the much bigger problem.

A: Well, my mother and your mother told us to look both ways before we cross the street. You know, that’s just smart. A crash is typically never one factor. It has, typically, error on both sides. The way to avoid a crash is for pedestrians and bicyclists to protect themselves as much as possible, and absolutely the motorists, they’re driving a lethal weapon if they’re not appropriately reacting to pedestrians and cyclists. I’m not necessarily defending them. But everybody in the whole driving ecosystem has to play their role in making it as safe as possible.

Q: What advice do you give to people whose kids are turning 16? As the author of the book “Survive the Drive: A Guide to Keeping Everyone on the Road Alive,” did you let your kids drive when they were teenagers? [The second edition was published last year by Virginia Tech Publishing, and a digital version can be downloaded for free.]

A: I did. The book has a pretty long chapter on teaching your kids to drive. Many states have some kind of graduated driver’s licensing laws. Some are more stringent than others. …. If you look at the literature, you can sort of create your own graduated driver’s licensing program. It depends a lot on where your kids are driving and how far their commutes are and what the purpose of their trip is. But you want to limit the number of passengers and you want to limit the length of their trip, because teens aren’t used to driving while fatigued and they get more fatigued than they expect. … A study in Minnesota showed if you delay high school by some period of time, so that the kids are driving a little later in the morning, it saves lives … A lot of parents trust their kids, they want to trust their kids. But I view it like a treaty with a foreign power. You need to trust but verify. You want to pay attention to things like the condition of the car. You want the kids generally to drive a family car instead of their own car. You want to look for dents and scratches in the car. You want to understand where they are and who they’re driving with.

Q: In an earlier version of your book, you said Americans could cut teen fatalities dramatically by having kids drive the newest car in the family, not older hand-me-downs.

A: This is still true to some extent. The tendency is, ‘I drove an old car when I was your age, and so you get the 1974 Gremlin and I’m driving the Audi A8.’ But there’s a huge difference in all of the safety features associated with those cars. … As the fleet gets newer and newer, there are more and more safety features, so that difference is probably going to decline. But I’m certain it’s still there.

Q: What are things the U.S. government could do to cut the number of road deaths every year, given the persistently high numbers? (Deaths topped 36,000 in 2019 and were up in the first nine months of 2020, the National Highway Traffic Safety Administration reported.)

A: A big one that’s been proven to be effective in Europe and other places is photo enforcement. In the D.C. area, it’s pretty common. It’s not common around the country. But it’s been proven to save lives. I commuted to D.C. a few times, I’ve actually gotten a ticket or two. There around the Kennedy Center it goes from 45 to 25 in a short period of time and the cameras got me. That’s a little embarrassing. But, photo enforcement around intersections, automated speed enforcement, is very, very effective.

In general, greater enforcement is better. As you drive from state to state, you can really tell some of the states don’t do much enforcement, 15 to 20 miles an hour over the speed limit is not unusual. Eighty-five or 90 miles an hour, even in a modern car, that becomes a serious issue. Distraction enforcement, seat-belt enforcement, certainly those are big deals. Seat-belt rates have been climbing over the years, but there’s still a lot of disparity between states. Some states are well over 90 percent and some states are still in the 70s.

If you talk about drinking and driving, which is a terrible thing, in general the laws are pretty severe in that regard. I don’t know that locking people up for longer periods of time would be effective. It’s more just getting those people off the street, and that goes back to enforcement. But alcohol is always a big deal and continues to be.

Q: What are things an ordinary driver can do to reduce the chance of dying?

A: The key is staying alert, attentive and sober. If you keep your eyes on the road, if you only drive sober, and don’t drive when you’re too tired, and generally you’re just engaged in the driving task, it reduces your chance of a fatality substantially. Now, it doesn’t reduce it to zero, because you can get hit by somebody else, but you really can control a lot of the risk.

And it also gets to thinking, What car do I buy? You may want to buy a 2013 instead of a 2010 or a model X versus model Y, just because the safety ratings are so much better.

Q: People keep crashing or dying in Teslas with automated features turned on. Why does this keep happening?

A: There are different levels of automation. Even the definitions of the levels are changing. But what is typically called level two, or mixed-function automation, is where you’ve got significant automation features, but the driver is still supposed to pay attention. If you think about driving a vehicle that more or less drives itself, but you’re supposed to pay attention, it’s really what humans are bad at. This just goes back to Three Mile Island. With not much to do, your job is to pay attention and wait for a rare event to happen and be ready to react at a second’s notice. People just aren’t good at that. They over-rely on the automation, whether it’s a Tesla or other kind of car, and then they get into a lot of trouble. Now Tesla’s a little bit of a unique car, in that Tesla is sort of relying on their users to be their beta testers of new software. That’s unusual in the car industry. I think in that particular case that may be why you get a little more of those kind of issues.

Q: How will fully automated vehicles develop over the next 5 to 10 years?

A: I think they’re coming. I don’t think there’s any doubt that they’re coming. The industry was somewhat optimistic about how soon they would come and how solvable the problems were, but it’s taking significant time. There is a lot of progress being made for sure. But there’s a reason why they’re testing in Phoenix and Austin, because the weather’s always good, particularly in the Phoenix area. It’s more modern, all the roads are laid out in grids. It’s fairly simple to navigate, relative to Boston or Washington, D.C. Washington has weather issues. It has spokes and hubs and bizarre intersections and roundabouts and all sorts of things, and that’s going to be much more of a difficult problem …. Beyond that, if you’re driving in mixed traffic, drivers create a lot of variance in the system, right? They don’t always follow the rules, and they don’t always follow the rules well. A study we did years ago found that when drivers pull up to make a stop and then make a right turn after stopping, less than 50 percent stopped at all. The average speed for those that didn’t stop was 11 miles an hour. … Another example is interstate highways. The average speed on an interstate highway in the U.S. is greater than the speed limit. So do you let the fully autonomous vehicle exceed the speed limit? Does it follow the flow of traffic? Or is it just going to be kind of in the way all the time, as the rest of the traffic is trying to get around it, which could create more risk? It’s a really hard problem for automated vehicles to predict and interact with human variability.

Q: How’d you get interested in transportation in the first place?

A: Even going back to my undergraduate degree, I was a human factors engineer, which means essentially you design systems for safe and efficient human use. That’s always been my interest. But I tended to be on the safety side as opposed to the efficiency side. If you’re interested in safety, sooner or later you’re going to migrate to vehicles, because that’s by far where the most serious injuries and fatalities occur.

Q: What has surprised you the most during decades researching transportation?

A: I am always surprised by human behavior. That’s what makes it sort of interesting and frustrating, in some sense, at the same time. The best most recent example is how people behaved during a pandemic. Traffic goes down. So what’s the behavior change? They drive faster …

Driver behavior over the years has always shocked me, like people making a right-hand turn at an average of 11 miles an hour when they’re supposed to have stopped, or 22 percent of pedestrians even looking up at a novel vehicle. Those are the things that keep us all employed. But those are also the things that make it interesting and challenging to come up with countermeasures to continue to reduce injuries and fatalities. That’s always been the most surprising part, the most interesting part and the most challenging part.