A future of driverless, electric cars is just around the corner, right?

We're shifting to more sustainable solutions like car sharing, right? Right?

There's been lots of hype about car travel and the promise of greener, more convenient, and cheaper ways to get around.

But where are these concepts actually at right now? And what are the complications and challenges holding them back?

We spoke to some experts to get their take.

Driverless cars

The media's been touting the automotive industry's virtues of driverless cars and presenting an "almost fantasy-like vision" of what they'll look like for years, Ashley Nunes tells ABC RN's Future Tense.

But the senior research associate at Harvard Law School says there are a number of reasons predictions have fallen short.

There's the cost.

Dr Nunes says much of the talk from big carmakers has been around the so-called robotaxi model — the promise that being able to order a driverless car whenever you need one would be cheaper than owning a car.

But he says that's looking unlikely.

"We have done some work in which we estimated these costs to be close to three times more than owning a vehicle today."

He says users will end up paying for the inefficiencies that already exist in the industry (such as the amount of time cabs sit empty), as well as the cost of remote operators who would be needed to step in in the event of a malfunction.

Then there's the cost of infrastructure — ensuring roads are clear and painted so they can be recognised by sensors.

"It's important to remember that you can have the best piece of technology, but that piece of technology, is in a way, worthless if people are unwilling to pay for it."

There's also the challenge of making them — and making them efficient.

Dr Nunes says while the computing systems in cars today have between 80-100 million lines of computer code it's expected driverless cars would need at least double that.

"The challenge here, of course, is equipping the vehicles with enough computing capacity to be able to churn through these gigabytes and gigabytes of data that are being produced."

More computing capacity, he says, means more weight.

"The more computers you squeeze on board these vehicles, the more fuel inefficient you actually make the vehicle."

Electric vehicles

The good news is sales of electric cars are rising.

But there's a catch.

They still only make up about 2.6 per cent of new cars sold each year — that's about 2.1 million cars.

China is buying a lot of those new electric cars. About 5 per cent of their new car sales are electric, in the European Union it's 3.5 per cent.

Australia's at just 0.6 per cent.

Like driverless cars there are challenges standing in the way of an electric car revolution.

There's the need for infrastructure like charging stations, and there are concerns electric vehicle taxes will slow the take-up of the technology.

ABC science and environment reporter Nick Kilvert says if you're charging from the grid in Australia, you're contributing to the burning of fossil fuels (though some states have a better mix of coal versus renewable power).

"How green an electric car is, compared to a petrol car, depends on how green the grid is you're charging it [from]," Kilvert says.

Your home solar might be able to help.

"However, electric cars, they have huge batteries, they need a lot of energy to charge those batteries — more than any household solar system array can provide," Kilvert says.

"So you're still going to need supplementary power … and that usually means some element of dirty fuel."

There are also issues of the demands on the power network. One charging station built in Adelaide a few years ago was equivalent to adding 100 new homes to the grid.

The US is experimenting with using an electric car as a back up battery for excess solar power, that can then be fed into the grid at times of high demand.

Key to some of that technology will be the development of bigger batteries, such as Tesla's promised (but yet to be unveiled) "million-mile battery".

Shirley Meng from the University of California, San Diego says a battery that outlasts the car it's in would open up a lot of possibilities.

"I think this will fundamentally change people's mindset. [That a] battery is no longer disposable is actually an asset," Dr Meng says.

She says the batteries could also be used in the battery banks to store large amounts of power from wind and solar.

Pooling ride share trips

Another much-hyped transportation shake up is pooling ride share trips, where a driver picks up and puts down multiple passengers along the course of a journey.

Dr Nunes says the big ride sharing companies such as Uber have struggled to get people to pool rides.

"Ride pooling is arguably the single best thing we can do to reduce emissions on the road," he says.

"And, of course, we don't even need driverless cars for this. We could pool today."

But he says the challenges are:

• Privacy — being OK sharing a car with a stranger.
• Time — sharing a ride's likely going to make the trip longer, and many people want as quick a trip as possible.

Car sharing

Car sharing services hope that rather than buying a car, you'll hire one of their conveniently parked cars when you need one.

Wulf Stolle studied the use of car sharing across Europe and North America for global management consulting firm Kearney.

He says there had been high hopes in Europe that it would reduce the number of cars on the road, providing a more sustainable way for people to get around, but the reality has been sobering.

Dr Stolle's research found more than half of car sharing members in the UK and the US reported using the service less than once a month or not at all.

He says there's a smaller core group of regular users, but the reason they were using car sharing wasn't so much about being green, it was because:

• They think it's a comparatively cheap way to get around.
• They're expecting a high level of convenience.

He says that combo makes the economics tricky for car share businesses because:

• People are expecting it to be cheaper than alternatives like public transport or taxis.
• People are expecting cars within walking distance, meaning you need big fleets in densely populated areas.

"So on the one side, I cannot earn too much because there is a ceiling because I'm competing with other modes of transportation.

"And on the other side, my customers are expecting a car standing on every corner.

"If I put these two together, these are the ingredients for a very challenging business case and that's also what we are seeing."

The economics of car sharing really only add up in very densely populated urban areas, Dr Stolle says.

He looked at German cities with suitably populated areas and estimated that even if everyone in these areas was to switch to car sharing, the country's car ownership would only be reduced by 5 per cent.

"This simple calculation in itself already tells you that the highest hopes and the hype that car sharing was hoping to live up to were actually, from the beginning, never realistic."

Disappointingly, from an environmental perspective, he says in cities like Berlin and Hamburg car sharing hasn't affected new car sales, but has had an unintended consequence.

"They're using it at the expense of public transportation," he says.

"What we are clearly seeing is car sharing has not been promoting the switch from ownership to shared, but actually has been promoting the switch from using public transportation to car sharing offerings."