gravity to bring down the water to cities gradually. But some, such as the aqueduct at Aspendos in Turkey, had sections where they had to go uphill. So how did the Romans get water to flow upward?

The Romans used a few methods, including siphons and various water-lifting devices, experts told Live Science.

Inverted siphons

One strategy was a system called an inverted siphon (sometimes simply called a siphon).

At Aspendos, in southern Turkey, there is a second-century-A.D. Roman aqueduct with inverted siphons that scholars have reconstructed with a virtual modeling simulation. To get water through a valley, the Romans built a "header tank" on one end of the valley and a slightly lower "receiving tank" (or "outlet tank") on the other side. In the valley, they constructed two towers between the tanks, Paul Kessener, a researcher in the Department of Language and Culture Studies at Radboud University in the Netherlands, noted in an article published in 2000 in the Journal of Roman Archaeology.

As water dropped down a steep hill, the resulting pressure pushed it up the first tower before dropping it steeply down the other side, with the force allowing it to climb the second tower. The water eventually reached the receiving tank on the other side of the valley and continued toward the city of Aspendos.

It was important to prevent air pockets from forming as the water went through the inverted siphons. The header and receiving tanks were relatively large, allowing air bubbles to escape, Giovanni De Feo, a professor of industrial engineering at the University of Salerno in Italy, noted in an email.

"As the flow entered a relatively large chamber, its velocity decreased, allowing air bubbles to rise naturally to the water surface and escape through the open top of the structure," De Feo explained. This reduced the risk of air pockets forming.

The Romans tried to avoid using inverted siphons, said Charles Ortloff, a research associate in the Department of Anthropology at the University of Chicago who has a background in both engineering and history. When "Roman engineers encounter a valley, rather than construct a siphon, they [preferred] to build a bridge with a top channel to cross a valley," Ortloff said in an email. One example of this is at the Segovia aqueduct in Spain, which has a stunning bridge that still survives today.

Roman water-lifting devices

While the Romans used inverted siphons to move water upward in an aqueduct, they employed other devices to push water out.

Perhaps the best known of these devices is the Archimedes screw, which was sometimes used to help lift water from rivers to fields. (It was allegedly designed by Archimedes, a Greek inventor who lived during the third century B.C. However, it might have actually been invented at an earlier time, noted historians Stephanie Dalley and John Peter Oleson in a 2003 paper.) When "turned by use of animal power, [it] can effectively raise water from lower river heights to higher land area heights," Ortloff said.

The Archimedes screw "consisted of a wooden shaft that had [curves] of thin and flexible willow or wicker branches one stuck on top of the other, so that an endless screw was created," the Kotsanas Museum of Ancient Greek Technology's website notes. This screw was placed within a wooden pipe, and the "device was placed in the water with an inclination of 30 degrees," the museum representatives wrote. As the screw was rotated, it lifted the water.

Water wheels were also used to lift water, including in Roman mines. "The water wheel is a device that raises water and that is made up of several buckets that are fastened to a big wheel," scientists wrote in a 2024 paper. This "kind of wheel resembles a carriage wheel but it is larger and features buckets to catch water in addition to its larger size," they explained.

Another device, sometimes known as Ctesibius' pump, "was hand-moved, operating a wooden lever with a swinging motion," the scientists wrote. It had two cylinders connected to a central chamber through pistons, and the driven water exited through a nozzle connected to the central chamber.

Whatever method was used, the Romans would not let an uphill climb stop them from bringing water where they wanted it to go.

From Augustus to Nero, see how much you know about ancient Rome's famous leaders with our Roman emperor quiz!

'> How did Roman aqueducts get water to go uphill?

"If anybody had said, 'You're going to work with big cats for 25 years of your career,' I would have said 'No, I don't know anything about big cats,'" he told Live Science. "But I learned from scientists and local people," he added. "That was very, very important — that's what, to me, was the biggest change in my life."

Together with his wife, author and environmental journalist Sharon Guynup, Winter has helped change laws around big cats in the U.S.; revealed the horrors of the Tiger Temple in Bangkok, resulting in its closure; and took an iconic photograph of the cougar P-22 beneath the Hollywood sign, which eventually led to the creation of the world's largest highway wildlife corridor over Highway 101 in California.

In their new book, "Big Cats" (National Geographic Books, 2026), Winter and Guynup provide a retrospective of their careers, looking at the fragility of these predators, the conservation work helping to save them, and the challenges they still face. Live Science spoke with Winter about his career, the changes he's seen, and why he's hopeful for the future.

Hannah Osborne: You've traveled all over the world and seen so many things. Is there one photograph that really sticks out for you, one that you come back to and think about?

Steve Winter: I always look at the images that have had an impact at the time. That makes a huge difference to me, because in the end, I know that in taking this [photograph], not only did I succeed beyond my wildest expectations, but it's making a difference in the world. Right now, I have just been putting remote cameras up on what will be the world's largest wildlife overpass, and that was started by my Hollywood cougar picture of P-22, Puma 22, under the Hollywood sign. [Editor's note: The common names cougar, puma and mountain lion all refer to the same species, Puma concolor.]

That changed so much in Los Angeles. I've never seen a city be transformed in their love for the fact that they have a mountain lion in a park in the city. What came of that was [people] thinking, "Hey, maybe we should connect these areas where these animals are living." [Editor's note: The Wallis Annenberg Wildlife Crossing over the 10-lane Highway 101 that was inspired by the cougar P-22 is due to open Dec. 2.]

To think about that is pretty amazing, so right now, P-22 and the Hollywood cougar is my go-to image.

He became a celebrity in the land of celebrities; people loved him. There's a P-22 day; schools are using urban wildlife in their curriculum. The LA Natural History Museum has a permanent exhibit, and what is right in the center of it? The Hollywood cougar picture.

HO: How did the P-22 photograph come about?

SW: As wildlife photographers, we will often go to these meetings where people are gathering to save elephants, to save this, to save that. So I went to meet the scientists that worked with these cats in the largest urban park in the United States. I asked Jeff Sikich, a biologist for the National Park Service, "[Do] you have a lot of trails in that park? Do you have any that the cats walk on where you could see the lights of LA in the background?" He kept saying no.

When you're working with camera traps, it's very important to visualize the picture in your mind that you're after [when] you visit a spot. I just said, "Well, Jeff, you know what would really tell the story of urban wildlife is if we had a mountain lion under the Hollywood sign." He looked at me like I'm crazy, and said, "There's no mountain lions in Griffith Park." I said, "If anything changes, let me know."

Eight months later, I got a text. They had a trail camp set up to census bobcats [Lynx rufus] in the park, and there was P-22.

With camera traps, you don't need to sit, and I learned that from the beginning. For the second story I did, it was photographing a quetzal, which is a sacred bird of the Maya and the Aztecs. I knew nothing about birds, either. It's got a meter-long [3 feet] tail. I was enamored by the fact that it had a historical background — they used quetzal feathers as a form of currency; they were sacred birds.

I loved all that, but working on that story in a cloud forest in Guatemala on top of a mountain all by myself, every morning I'd come down and set my camera up on the tripod [near the bird's nest], and then take it away at the end of the day. I'd walk back, and all of a sudden, the hair on the back of my head would stand up and on my arm, and I'd get this tingling feeling and it's like, what's going on? I'd turn around. You can't see anything in a rainforest or a cloud forest because the proliferation of life is everywhere. One night when I'm reading my book in the one room shack that I was staying in my bunk bed, all I hear is the stairs creaking. Then I hear the floorboards creaking. Then I hear scratching, and then sniffing, outside the door.

I grabbed the walkie-talkie to call Juan Carlos, the naturalist that I was working with. He would find the quetzal nests for me. I asked him, in Spanish, "Juan Carlos, what is this?"

And he said, "Oh, Steve, don't worry; it's just a black panther [Panthera onca]." I've been there five weeks, and I said, "Well, how come it took you so long to tell me there was a black jaguar here?" And he said, "We didn't want to worry you."

HO: Throughout the book, you look at topics like poaching, captive tigers in the Tiger Temple in Thailand, and the way they're kept in the U.S. for entertainment. And a lot of these things are still going on. How do you cope with seeing that side of their lives?

SW: When I was first working on tigers, I was in Thailand. I was wanting to work in Thailand and Sumatra because they were the two subspecies that experts said may go extinct. I was working with the most incredible group of scientists I've probably ever worked with. They were trying to save the Indo-Chinese tiger [Panthera tigris corbetti] in Thailand.

But close by was this place called the Thai Tiger Temple. And I said, "Hey, guys; I'd like to go there." And they said, "No, Steve; don't go. These are bad people, and we think they're involved in the black-market trade of tiger parts and tigers to Laos and then into China."

That's a good reason for me to go if you don't want me to go. The first thing I saw was this huge sign that said "conservation." This was a Buddhist monastery. For some reason, the abbot had been given a tiger cub about 10 years before, and he fell in love with tigers. So they started a tiger tourism operation that brought in at least $3 million a year.

I could see something was fishy right away, because by then, I'd learned a lot about these cats. They kept saying that they always had 150 tigers. But you could pet tiger cubs for Instagram selfies or bottle-feed them 365 days a year. If you're breeding tigers, what are you going to have? More tigers. Something was happening to them, because the death rate wouldn't take over the birth rate when you're speed-breeding cubs, which is what they were doing. A female has cubs; they take them away immediately so she'll be ready to have another litter. You can only use the cubs for three months because after that, they're too big to pet.

They had all these tourist things where you could get a selfie with a head of a tiger in your lap. I was saying, "Why are these tigers acting so sleepy?" They're taking this giant head of a tiger and putting it in somebody's lap that's sitting on the concrete. You would think that if you put the head of a tiger in your lap, you're going to end up with your head in their mouth.

[Editor's note: Winter and Guynup worked together on an investigation into the Tiger Temple in 2016, which eventually led to it being exposed for its abuse and connections with the illegal wildlife trade. Shortly after, the Tiger Temple was shut to the public.]

Sharon did the investigation, and I already had pictures. But we went to do a video and go visit the temple again … By the time we got done, the TV stations in Bangkok had taken the video and showed it all over on the nightly news. We kept working on this, and Sharon wrote four more stories. And after the last one, the Thai government was inundated with people calling for the prime minister to shut it down. They went in with the army and the police, and what they found was horrific. They went to the freezer. There were tigers hanging on meat hooks, cubs in jars, with a little Thai flag on them. They shut it down.

Stopping this is really important. After that, we did a story on tigers in the U.S., which was very difficult psychologically. It was one thing to see them in Thailand, but we had always heard that there were more tigers in the United States than there are in the wild, and people would go, "What are you talking about? We don't have tigers here."

Sharon and I … we found a lot of the same speed-breeding cubs at these roadside zoos, whether it was Doc Antle's Myrtle Beach that was $500 a day, or some dumpy little place on the road down south where you can give them $10 to look at a tiger. They were everywhere.

After that story came out, the National Geographic Society gave a copy of this 30-page story that we had done for the magazine to every member of Congress. We got this text on 20th December, 2022, that President Biden had signed the Big Cat Public Safety Act, which outlawed all that. We were part of getting this law passed, which was incredible.

HO: What are some of the biggest changes in conservation you've seen over your career?

SW: Conservation was changing a lot in the '90s and 2000s. Alan Rabinowitz [a zoologist who served as the president, CEO and chief scientist at Panthera Corp., a nonprofit conservation organization devoted to protecting wild cats] had this idea after he had a lot of scientists in Central and South America give him data on where they were working and where jaguars were. When he took it away and just showed the locations, he goes, this is a corridor, a natural corridor, because now we're talking a lot about connectivity and how roads get in the way. It's like animals are in prison because they can't cross these big freeways or even small ones. Find out where animals are, their migrating paths, and put in an overpass or an underpass or something.

All this was happening, all this new science, new conservation. That was all spearheaded by the work of [biologist and conservationist] George Schaller, who became a friend of ours. What a life that we've had — and are having. We're still working on the connectivity part right now.

HO: Are you hopeful for the big cats in LA?

SW: Oh, definitely. The ones that live in the Santa Monica National Recreation Area will be able to cross the 101 and then go all the way to San Jose. They could actually then hug the top of a certain mountain and get close to San Francisco, which is incredible to think about now. It's a huge metropolitan area, so you're leaving one, going to another. But there's so much land in between, and they can cross safely.

HO: What made you specialize in big cats in the first place, and what's the draw that keeps you coming back?

SW: Big cats are so charismatic and, to me, mystical. And they're an umbrella species, so if you save the largest predator, which is usually a big cat in any landscape, you save everything underneath it.

I was just taken over by these animals. National Geographic had never done a jaguar story before. I found out really quick why: You can't see them. I tried to use remote cameras, camera traps, but they're really smart. They'll go around them, so they don't have the flash going off or they don't like the sound or the smell of meat on these waterproof boxes and the cords and all that.

I just fell in love with big cats, and what a life to be able to work with every one of them. The only one that was on my list that I haven't done is the Amur tiger, Siberian tiger [Panthera tigris altaica]. When I was ready to photograph them with the scientists that had been monitoring them for over a decade, [the tigers] got canine distemper and about 60% died.

Big cats really bounce back when you give them protection, and there was protection given after you lose this many. All the study tigers that had the GPS collars on, the ones they could monitor, died. But the population bounced back, and there's more now than there were before.

I won't get to photograph Amur tigers. And the reason is, there's people — locals — who are working on it, and they're doing an incredible job. I've got a book here that has all the cats that I've worked on. The impact these stories have had, and the change that's come about, is what really makes me proud.

This interview has been condensed and edited lightly for clarity.

Help us improve Live Science Pro: We're always trying to make our content better. Leave us feedback about Pro here.

'> Photojournalist Steve Winter on his iconic Hollywood puma image, the illegal tiger trade and having a black panther knock on his door

So does writing speed up cultural change or slow it down?

Russell Gray, a professor in the Department of Linguistic and Cultural Evolution at the Max Planck Institute for Evolutionary Anthropology in Germany, heads a research project investigating how writing affects the way languages change. His team uses methods borrowed from evolutionary biology to trace languages through family trees — similar to the way biologists trace species.

Language is one element of culture that researchers can measure to determine whether writing speeds up or slows down cultural change.

"The obvious answer," Gray said, is that writing slows culture down because writing "is all codified and specified and people get trained in it." Gray doesn’t think the obvious answer is necessarily the right one. But other researchers agree that writing can lock in ways of thinking.

"Writing can lead to what learning psychologists sometimes call 'canalization,'" Charles Perreault, an associate professor in the School of Human Evolution and Social Change at Arizona State University, told Live Science in an email. "It can narrow the range of ways people think about a problem. When a rule, method, or story is written down, people may come to see it as the correct version … and may not even consider that a better or different way could exist."

Religious texts and legal codes are good examples. In both cases, the interpretation of rules written hundreds ‪—‬ or even thousands ‪—‬ of years ago shapes the way things are done, long after the circumstances that produced them have changed.

This idea shows up in artistic expression, too: A 2017 analysis by ethnomusicologist Patrick Savage looked at more than 4,000 British-American ballads from the 16th through 20th centuries and found that written melodies changed less than those shared through oral tradition.

But there are also ways that writing may speed up cultural change.

"Before writing, much cultural knowledge had to be stored in people's brains," Perreault said. "That has obvious limits."

People forget things they don't study routinely, and when people die, their knowledge often dies with them. Because writing moves information storage beyond the human brain, it can reduce those losses, Perreault said.

"If writing prevents knowledge from being lost, and if it also helps information spread through a society, as with the printing press, then it could accelerate the ratchet effect of cumulative cultural evolution," Perreault said. "But this remains, to some extent, a hypothesis."

By the book

One reason the question of whether written language speeds or slows cultural evolution is that writing is hard to separate from everything that comes with it.

Writing has been separately invented only around four times in human history — although "some people argue there's a fifth in India," Gray said — which means nearly every writing system on Earth descends from that handful. Those systems spread through contact; trade, war, religion and the other ways humans intermingle had their own effects on cultural change that are hard to untangle from the effects of writing.

Also, "mass literacy is quite recent," Gray said. "If you've got these written varieties that are just used by, often, religious elites, that's potentially going to have much less impact."

So which force wins? Both experts think writing speeds up cultural change, though neither can prove it yet.

"I would say that writing probably speeds up cultural change overall," Perreault said. Gray agreed, though he acknowledged that most people would guess the opposite.

Still, Perreault cautioned, "these are empirical questions that have yet to be answered empirically."

'> Does written language speed up or slow down cultural change? 0.5% of samples tested positive during the week ending Sept. 27, 2025.

"This particular year, it appears to be starting early — like right now," Dr. William Schaffner, a professor of preventive medicine and infectious diseases at Vanderbilt Health in Tennessee, told Live Science. Patients at clinics in his area are already testing positive for flu, he said.

The early uptick in flu is mostly unfolding in Western states, including Washington, California and Arizona. In Washington, for example, the share of emergency department visits diagnosed as flu climbed from 0.25% in the week ending Aug. 29 to 1.34% in the week ending Oct. 3, according to CDC emergency department data. That's a more than fivefold increase over six weeks.

Where the flu took off first isn't a warning sign in itself, Schaffner noted.

"There's nothing unusual about flu starting in the West Coast and moving east," he said. Recent seasons have more often begun in the Southeast or Midwest, he noted, but "it can start almost anywhere."

Leading with H1N1

Nowadays, seasonal flu is caused by three subtypes of flu viruses: two subtypes of influenza A, called H1N1 and H3N2, and the Victoria lineage of influenza B. (A second subtype of influenza B used to circulate but is now thought to be extinct.)

Last season, a fast-spreading version of H3N2 known as subclade K dominated. The CDC classified the 2025-2026 season as highly severe for children, as at least 195 children died of flu-related causes.

Schaffner likens influenza A and B to siblings. "They're very related, but they each have their own individual characteristics," he said. Influenza A strains usually cause the biggest outbreaks early in the season, while influenza B strains "kind of smolder along" and account for most cases toward the end, he noted.

This year, H1N1 has taken the initial lead. Of the influenza A samples that public health labs subtyped during the week ending Sept. 26, 96% were identified as H1N1, according to CDC data. That doesn't mean H1N1 will continue to dominate throughout the season; it just gives a snapshot of what's happening now.

The dominant strain matters because flu is "a moving target," said Dr. Paul Offit, director of the Vaccine Education Center at Children's Hospital of Philadelphia. The virus constantly mutates — especially hemagglutinin, the protein on the virus's surface that it uses to latch onto human cells. Hemagglutinin is the main target of flu vaccines.

An early start to the season doesn't guarantee it'll be a severe one, either. In its 2026-2027 season outlook, the CDC projected that this season will likely be moderate, although it has only low-to-moderate confidence in that forecast.

When to get vaccinated

Everyone 6 months and older is recommended to get an annual flu vaccine.

Influenza is especially dangerous for children under 5, adults 65 and older, people with chronic health conditions and pregnant people, as these groups are more prone to severe infections. Serious cases of flu can lead to complications such as pneumonia, sepsis, and brain or heart inflammation, and in some cases, they can be deadly. Tens of thousands of people die of flu each season in the U.S.

For flu vaccination, timing matters. The CDC generally doesn't recommend vaccination in July or August for most adults, because the shot's protection can wane over the course of a season. But with flu arriving early, "October is the ideal time to get vaccinated, and even more so right now," Schaffner said.

When circulating strains' features differ from those captured in the vaccine, "that usually predicts a more difficult season," Offit said. That said, it's too early to know if this year's flu shots are a good match for the circulating flu viruses.

Protection begins building right after you get the shot, but it takes up to about two weeks to reach full strength.

How much protection a flu vaccine offers varies by season, depending partly on how well its formulation matches the strains that circulate. Offit said that protection against symptomatic illness varies by age group and that the vaccines are "a little more effective" at preventing more severe illness. In terms of flu cases that prompt people to seek medical care, the shot has been 29% to 56% effective over the past decade, the CDC estimates.

While the vaccines are less reliable at preventing mild cases of flu, Schaffner said, they work best at "keeping you out of the hospital, keeping you out of the intensive care unit, and keeping you out of the cemetery."

The CDC's 2026-2027 guidance keeps its recommendation of an annual flu vaccine for everyone 6 months and older, with high-dose and adjuvanted shots preferred for adults 65 and older. (Adjuvanted shots contain an extra ingredient to help rev up the immune system.)

There's also a new option: In August, the Food and Drug Administration approved mFlusiva, the first mRNA flu vaccine, for adults 50 and older. (You can find out where mFlusiva shots are available near you using Moderna's vaccine finder.) With the mRNA shot, "you're less likely to get symptomatic disease," Offit told Live Science.

Traditional flu shots contain purified pieces of the virus itself, Schaffner explained. With mRNA, the vaccine contains a "blueprint" of those proteins — essentially a set of genetic instructions that the body's cells then use. In mFlusiva's case, those instructions code for hemagglutinin (the protein on the virus's surface that it uses to latch onto human cells) from each of three flu subtypes, Offit said. The mRNA then breaks down in the body, Offit noted. It "cannot influence human genetic material," Schaffner emphasized.

Whether this early start gives way to a heavy flu season should become clearer in the coming weeks, as the CDC's weekly surveillance reports will show whether cases keep climbing beyond the West.

This article is for informational purposes only and is not meant to offer medical advice.

'> 'October is the ideal time to get vaccinated': Flu season is kicking off early, experts say

Your eyes are on the stunning scenery, taking in the vistas along Route 66 or the grandeur of the Rocky Mountains, or you're catching up on messages. Your hands barely touch the wheel, and your foot doesn't push a pedal. Your car communicates with others on the road, so there's no need to brake suddenly or swerve. That's because it knows a vehicle five cars up from you has done so, and all those in between are slowing at exactly the right pace to avoid dramatic changes in trajectory.

And when you park for the night, your car makes you money, selling the excess energy it's harvested from its paint back to the grid. Or maybe you don't feel like being in the driver's seat at all, so you hail a self-driving car and take a nap in the back seat in between adventures.

Some of that scenario may become a reality in the next 10 years, at least for those who are using the most cutting-edge cars on the market. Although there's some heavy speculation involved in that futuristic vision, vehicle manufacturers are already incorporating increasingly sophisticated automated driving technology into high-end personal vehicles, and self-driving taxis are coming to dozens of U.S. cities.

What's more, dramatic changes in range, cost and charging speed for electric vehicles (EVs) are arriving at a rapid pace. While some of these technologies may not wind up in personal cars, others are already taking to the roads.

An ecosystem of connected vehicles

Some car models within the next decade may interact with their surroundings in new ways, including by communicating with other cars to avoid collisions, drawing energy from natural sources, or letting drivers get paid for sending their cars' unused energy back to the grid.

If you're driving an EV, you might avoid the hassle of finding a charger when you're at work or running errands. In 2024, EV company Aptera unveiled a prototype car equipped with solar panels. Those panels — on the car's hood, roof, dashboard and hatch — allow the vehicle to travel about 40 miles (64 kilometers) per day on solar power. That's more than the average American drives per day. Aptera's vehicle can also travel up to 400 miles (640 km) on a standard electrical charge.

Some sunlight-powered cars might ditch the solar panels altogether in favor of a more integrated design. In 2024, Mercedes-Benz revealed it was researching a photovoltaic paint that could convert sunlight into energy for electric cars. In sunny cities such as Los Angeles, the company calculated, the paint could draw in enough energy to power the car for nearly 7,500 miles (12,000 km) per year. The tiny particles in the paint convert about 20% of the energy from sunlight into electricity, which is comparable to the efficiency of existing solar panels.

You might even be able to sell some of the energy stored in your car's battery back to the grid. EV owners could charge during the day or late at night, when the demand for electricity is lower and pay lower rates for electricity. Then, in the evenings when the electrical grid is under more strain and the price of electricity is higher, they could sell that stored energy back at a profit.

Standardized software programs that throttle EV charging speeds during peak hours already exist. Drivers can use them if, for example, they want to keep charging costs down by primarily charging their cars during off-peak hours when electricity costs are lower, or if they want to use electricity only from solar power to charge, said Rajit Gadh, a researcher who studies EV charging and scalability at UCLA. But the process for sending energy back to the grid is a different story. Individual manufacturers haven't yet landed on a standard way to tell cars when and how much energy to discharge, Gadh said.

"What is needed is really [for] every EV charging vendor ‪—‬ and every EV manufacturer, actually ‪—‬ to have this protocol built in, adhere to it in its full specification, and make it available," Gadh told Live Science.

With the right protocols, though, cars of the future will be able to do more than interface with the electrical grid. "Vehicle-to-everything" technologies could enable cars to communicate with infrastructure and other vehicles to avoid traffic and collisions.

Some cars today are already equipped with vehicle-to-vehicle (V2V) communications. These systems use short-range radio signals to alert other V2V-equipped vehicles of the car's speed, direction of travel and braking patterns. The radio signals can travel about 1,000 feet (300 meters), allowing the vehicle to receive data from cars that are not in the driver's line of sight.

V2V systems could help reduce traffic collisions by warning drivers about oncoming cars they can't see yet — for example, by alerting a driver to another car speeding toward an intersection or coming around a bend as the driver is passing another vehicle on a twisty, two-lane highway. Not all cars have the technology, though, so its practical utility is limited for now.

Hands off the wheel; eyes off the road

Some driver assistance technologies, such as lane departure warnings and cruise control, have been on the market in personal cars for decades. These technologies and more recent assistive features require the driver to be in control of the vehicle, but theoretically, they make driving easier. For example, Tesla's Full Self-Driving (Supervised) mode handles most steering and braking tasks, but safe operation requires the driver to keep their eyes on the road and be ready to take over at a moment’s notice. In the next several years, drivers will likely see new features that automate driving in more contexts.

Some of these features will allow drivers to take their attention off the road entirely and enjoy some in-car entertainment, as long as they're alert and able to retake control of the vehicle within a few seconds if conditions change. Technologies that fully automate driving in many circumstances within certain service areas will likely be in about 4% of cars on the market by 2035, according to a white paper from the World Economic Forum.

In cars equipped with these features, "you're still going to have driver controls, but under certain circumstances, it will be effectively an automated vehicle," Luke Neurauter, who leads the Division of Vehicle, Driver and System Safety at the Virginia Tech Transportation Institute, told Live Science.

Mercedes-Benz introduced its Drive Pilot system for two consumer car lines in 2022. On the entire German Autobahn network and on certain freeways between and around Los Angeles, San Francisco and Las Vegas, during heavy traffic, the system lets the driver turn their attention toward other activities, such as reading a book or eating lunch, while the car handles steering and keeping pace with other nearby vehicles.

But as the artificial intelligence (AI) models that control autonomous driving improve and become better able to handle unusual scenarios — often called "edge" or "corner" cases — on the road, drivers will be able to hand over control to their cars in more situations, said Rahul Jain, an electrical and computer engineer at the University of Southern California.

Future AI systems might "have some reasoning ability, and then because of that, it can handle these corner cases much better than current systems are able to do," Jain told Live Science. For example, a car might be able to better respond to an indecisive pedestrian who suddenly enters a crossing, assess whether to enter potentially hazardous conditions such as flooded roads, or safely navigate around unusual circumstances, such as construction work, on a highway.

While some systems will enable drivers to make fewer decisions, others that may roll out in the next several years will track a driver's attention and alert them with sounds, an indicator light or haptic feedback when their focus falters. These systems use cameras and software to track head position, eye movement and steering-wheel input to ensure drivers are focused on the road even when they're using assistive features such as lane centering, Neurauter said.

In addition to looking for distracted driving, the technology might expand to monitor drivers for fatigue and alcohol impairment, he added. That information could then affect "whether or not other features become active, or change how they act, based on the driver state at that moment in time," Neurauter said. Proposed legislation could make this technology a requirement in new vehicles as early as 2027, but technological hurdles and concerns over privacy and false positives could stall its implementation.

The technology could also assist drivers who become unable to safely operate the vehicle — for example, if the driver falls asleep or experiences a medical emergency. If a car detects that the driver is not holding the steering wheel or actively controlling the vehicle, it could send a series of visible, audible, or tactile alerts. If the driver doesn’t respond to those cues, a car might turn on its hazard lights and come to a stop. Some vehicle manufacturers are already rolling out such technology; for example, Volkswagen has made it available in all new vehicles from model year 2025.

Fully autonomous vehicles

While personal cars may not offer full automation, highly automated car services will become much more common as rideshare vehicles in major metro areas. In some cities, like San Francisco, commuters already rely heavily on autonomous vehicles from Waymo. The company has rolled out its cars in nearly a dozen cities —‬ including Dallas, Houston, Atlanta and Los Angeles —‬ and has announced plans to expand service to more than 20 additional locales. Other companies ‪—‬ such as Nuro and Volkswagen’s MOIA ‪—‬ are testing their vehicles with human drivers on board before rolling out full public service.

Currently, autonomous vehicles navigate by combining information from preloaded, high-resolution maps and real-time radar, lidar and visual data collected by cameras and sensors attached to the car. An onboard computer uses that information to build a 3D map of its surroundings. Right now, the cost of these sensors makes them impractical for consumer vehicles, Jain said, but they’re becoming cheaper as manufacturers scale up production. The cars also use an AI model trained on both common and unusual driving situations to anticipate how other vehicles and pedestrians will behave and plot a safe path forward, Jain added.

Developing those high-resolution maps takes time, which is one of the main reasons autonomous rideshares aren’t available everywhere yet. Mapping usually involves decking out a car with high-end visual sensors and lasers and driving it throughout the region. Although cities like San Francisco have been mapped with this level of precision, much of the U.S. has not.

"It's very difficult to do overnight," said John Dolan, an autonomous-driving researcher at the Carnegie Mellon University Robotics Institute.

Complexities also tend to arise in city environments, where unexpected stops are more common and there are many pedestrians who behave unpredictably or jaywalk. But interstate highway driving doesn't face as many of those obstacles, and that could enable autonomous long-haul drives.

"[Autonomous] trucking, I would expect, would be the first thing that's going to happen" in terms of autonomous travel outside of major cities, Jain said. A few driverless trucks are already on the road: Pittsburgh-based company Aurora deployed the technology on I-45 in Texas, between Dallas and Houston, in 2025, with plans to expand across the southern U.S.

Longer range and faster charging

While there's speculation involved in predicting the range of self-driving capabilities available in a decade, the picture for EVs is a little clearer.

Right now, lithium-ion batteries dominate the EV market. Each cell in a lithium-ion battery has two electrodes, commonly a layered graphite electrode and a metal oxide or phosphate electrode, separated by a liquid electrolyte solution. Lithium ions migrate back and forth between these two electrodes when a person charges and discharges the battery.

Many electric cars with lithium-ion batteries can already travel more than 300 miles (480 km) on a charge. But that's not ideal for a long-range car trip, because charging stations are few and far between in the country's vast interior and charging takes longer than filling up a gas tank.

Solid-state batteries, which replace the liquid electrolyte with a solid electrolyte made of ceramic, polymer or sulfide materials, could make that cross-country trip in an EV a practical option, allowing an electric car to travel more than 750 miles (1,200 km) on a single charge. Some prototype battery packs can already achieve this range under controlled conditions. If a solid electrolyte were paired with an anode made of pure lithium, rather than graphite or hard carbon, it would allow the battery to store more energy than a lithium-ion cell of similar mass can.

Solid-state batteries may also enable faster charging. In current batteries that use liquid electrolytes, charging and discharging the battery too quickly can cause dendrites, thin branches of lithium that stretch across the cell and short-circuit the battery. A solid electrolyte could, in theory, block those dendrites, which would enable cars to charge fully in just 10 to 15 minutes. The higher energy density from a lithium metal anode also translates to a greater range than that from a similarly sized lithium-ion battery, Eric Wachsman, director of the Maryland Energy Innovation Institute at the University of Maryland, told Live Science.

Cheap EVs

Many of the raw materials that go into existing lithium-ion batteries are concentrated in a handful of geographic areas. In 2023, Australia, China and Chile mined about 85% of that year's lithium supply; China mined the majority of graphite used that year as well. And battery materials still make up a significant portion of an electric vehicle's cost.

Sodium-ion batteries could be cheaper and easier to source. Sodium is plentiful in Earth's crust, which means mining could be done throughout the U.S., potentially with a comparatively low environmental impact.

Such batteries also rely on a more widely available electrode material. Sodium ions are larger than lithium ions, so they don't fit in between layers of graphite like lithium ions do. Instead, sodium-ion batteries use hard carbon electrodes.

"When you cook at home and your soup boils over and you get this black ring around your pot, this is hard carbon," Maximilian Fichtner, a solid-state chemist at the Helmholtz Institute Ulm for Electrochemical Energy Storage in Germany, told Live Science. "You can produce this from sucrose or from biomass, from whatever. You can do that everywhere."

The downside is that hard carbon holds less sodium than graphite holds lithium, said Eric McCalla, a battery materials chemist at McGill University in Canada. That means sodium-ion batteries can't store as much energy relative to their mass, and they don't last quite as long as their lithium counterparts.

"The range won't be as large," McCalla told Live Science. "It'll be a fantastic commuter car, but you're not going to go on a family trip from Montreal to California so easily."

Manufacturers are already bringing sodium-ion technology to market. For instance, the Chinese company CATL began mass-producing the batteries in February and claims that their battery packs enable EV ranges over 250 miles (400 km).

But new technologies are being developed rapidly. For example, some scientists are making sodium-ion batteries that use solid electrolytes, combining the higher energy density of solid-state lithium batteries with the cost savings of sodium batteries.

This hybrid battery chemistry is still in the early stages of development, experts told Live Science. "I would be surprised to see them in cars in the next decade," McCalla told Live Science in an email. "I've been surprised before, though."

Bumps in the road

The future we're describing is the utopian scenario. But the biggest obstacles are likely not technological but rather regulatory, economic, political or cultural, experts said.

"We're going to try to guess at a timeline of when some of these things are going to come in, and odds are, we're going to be wrong," McCalla told Live Science. "Odds are, we're going to be slower than we think."

Solar panels may not wind up being the most economic or practical way to increase EVs' range, while scaling up manufacturing capacity for next-generation batteries is expensive and could slow EV adoption in the U.S. The utility of vehicle-to-vehicle communications, meanwhile, could be limited by a slow rollout and adoption of V2V-equipped cars among drivers.

Whether EVs will be ubiquitous will likely come down to their affordability relative to gas-powered vehicles, which is affected not just by manufacturing and technological advances but also domestic policy choices, such as whether to subsidize EVs or their charging networks.

One challenge for manufacturers is that the automated features drivers prefer may not always be safer. A recent review of automated systems found that those focused on driver safety, such as automatic safety or lane centering, tend to reduce crashes, while those focused on comfort, such as adaptive cruise control, can increase accidents. The authors proposed that such systems make it easier for people to disengage or become distracted while driving and possibly overestimate the capabilities of the system.

And there are other kinks to work out for autonomous rideshare vehicles. In December 2025, a horde of Waymos stalled during a power outage, clogging San Francisco intersections. The cars are programmed to treat dark traffic signals as four-way stops, according to a statement from Waymo, but they occasionally ping human operators for confirmation. During the outage, the number of confirmation requests spiked, leading to delayed responses — and lengthy traffic jams. The company says it has since released software updates that allow its vehicles to act more decisively at dark signals. But questions remain about how the fleet will respond in natural disasters, and some have expressed frustration that autonomous rideshare vehicles already slow down ambulances, fire trucks and police cars responding to emergencies.

One of the biggest roadblocks to automated driving is the regulatory environment, Neurauter said. Regulations on self-driving vehicles vary by state, and some, such as New York, effectively prohibit driverless vehicles entirely. Where they are legal, they often must carry higher insurance and pass testing, which could limit their rollout.

"When we get into automated driving, the driving behavior is being governed by software that's installed on a computer that's in the vehicle," Steven Shladover, a research engineer at the University of California, Berkeley, told Live Science. "That gets us into a messy gray area where both the federal and the state roles kind of overlap, and that's politically very complicated." For example, different states could end up with different rules for establishing who's legally responsible for an accident involving automated driving.

In 10 years, you'll almost certainly be able to drive from Los Angeles to Las Vegas in an autonomous vehicle. But if you want to drive to New York City, you might have to stop in New Jersey — and take a train into the city.

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'> Self-driving, solar-powered cars that talk to each other? What vehicles might look like in 10 years.