This blog post also appeared on Edmunds Auto Observer 
In movies like the iconic Demolition Man , we’re led to believe the future will be filled with cars well advanced from those on the road today (in the case of the Sylvester Stallone action flick, our cars will instantly fill with foam upon a collision). But what do the real experts think about the cars we’ll be driving in the future? For example, will our cars drive themselves like Google’s modified Toyota Prius ?
We answer some of these questions in our recently released report  that focuses on reducing the U.S. transportation sector's greenhouse gas emissions and oil use. The report details options available to automakers for building the cars of the future. It doesn’t attempt to predict the makeup of the car market in the future – that’s up to the consumer. Instead, the report highlights that many combinations of vehicles could significantly reduce oil use and greenhouse gas emissions in the future.
From much improved fuel economy to alternative drivetrains, a car in 2035 will look a lot different on both the inside and the outside if we embrace calls to move away from oil and reduce the environmental impact of our passenger vehicles.
In addition to simply driving less, there are three key factors in saving oil and reducing greenhouse gas emissions from cars: reducing friction, making lighter cars, and building more efficient and alternative drivetrains.
One way to improve fuel economy is to make cars more aerodynamic. Air and the road are the primary forces that act against propelling your car forward. If car makers reduce the aerodynamic drag (the resisting force of air) of a car by 10 percent, its fuel economy improves about 2 percent.
The Mercedes-Benz E-Class Coupe, and the Toyota Prius have the lowest aerodynamic drag of any cars on the market today, but General Motor’s EV1  bested the Prius by a wide margin.
The other factor holding your car back is the rolling resistance of your tires. Here too, a 10 percent decrease in rolling resistance increases fuel economy by about 2 percent. Many tire makers now offer tires with lower rolling resistance.
The next factor to consider is the car’s body weight. In this case, reducing weight by 10 percent yields a 7 percent increase in fuel economy. We will need a lot of help from scientists and engineers to achieve the substantial weight reduction, though. One possibility is manufacturing our cars with carbon fiber-reinforced polymer. We could achieve weight reductions of 40 to 45 percent with this strong and light material, which could improve fuel economy by about 30 percent.
The last factor covers the most ground – more efficient and alternative drivetrains. Here is where we have to introduce the alphabet soup of car types (see the table below).
First, it’s important to understand that there is still much room for improvement in the fuel economy of conventional vehicles. Primarily, this is because carmakers have spent the last two decades investing most of their research and development in acceleration performance and other attributes that were more important to consumers than fuel economy.
With a renewed focus on fuel economy standards  by the federal government, automakers are quickly responding to meet the new goals. If these standards continue to be ratcheted up over time, it is reasonable to expect that conventional cars will deliver 50 mpg by 2035.
A conventional hybrid electric vehicle (HEV) could get upwards of 75 mpg by then. These vehicles will be fierce competition for other alternative technologies in the future car market.
The alphabet soup of alternative cars
Major Market Barriers
Range in miles
Internal combustion engine vehicle fueled by gasoline or diesel
Ford Fusion 
Hybrid Electric Vehicle; vehicle with both an internal combustion engine and an electric propulsion system
Toyota Prius 
Electric Vehicle; electric propulsion vehicle powered by a battery
Cost, range, charging infrastructure, consumer acceptance
Nissan Leaf 
Plug-in Hybrid Electric Vehicle where XX is the maximum amount of miles that can be driven on battery power; the remainder of miles rely on an internal combustion engine fueled by gasoline
Cost, charging infrastructure, consumer acceptance
Chevrolet Volt 
Hydrogen Fuel Cell Vehicle; electric propulsion with power supplied by hydrogen-fueled fuel cell.
Cost, refueling infrastructure, consumer acceptance
Honda FCX Clarity 
One alternative has been available for some time – cars powered by biofuels. Presently, we blend biofuels with gasoline, and we will continue to do so into the future. Running cars almost entirely on biofuels (such as 85 percent ethanol and 15 percent gasoline, or E85) is possible today, but not very popular because a refueling infrastructure doesn’t exist. Our report expects blending gasoline with biofuels to be part of the future fuel mix but doesn't expect many cars to run purely on biofuels.
Another alternative drivetrain is just now entering the U.S. car market. 2011 is the year of the plug-in electric vehicle (PEV, which includes PHEVs and EVs) – the Chevy Volt, Nissan Leaf, and soon-to-be-released Ford Focus EV, Mitsubishi i-MiEV, Smart ED, and plug-in Toyota Prius are providing consumers a glimpse into the future.
A PEV offers a quiet and responsive ride because it relies on an electric drivetrain. Most people will be able to recharge their vehicle at home or work, removing the need to visit a gas station, but there still are factors that make it difficult for PEVs to compete with conventional vehicles today.
The key areas of progress necessary for PEVs are cost reduction, battery and electric drive improvements, and consumer acceptance.
Pure EVs have a range limited to about 100 miles today. The Chevy Volt overcomes the range limitation of the Leaf and Focus EVs with a backup gasoline “range extender.” But it does so at a cost nearly twice its conventional counterpart, the new Chevy Cruze.
Consumer demand will ultimately determine how many of these vehicles will hit the road. At the beginning, though, incentives provided by government can help. Consumers buying PEVs would allow automakers to reduce costs through the two pillars of cost reduction – learning-by-doing and economies of scale. Advancements in battery and electric drive technology could increase the range of a PEV to nearly 300 miles per charge, which would allow a PEV to compete with a conventional vehicle. To get there, however, automakers will need new kinds of batteries that aren’t commercially available today.
Lastly, consumers must accept things that differentiate PEVs from conventional gasoline vehicles, including rage limitations and the likelihood that refilling future cars may take longer than 5 minutes. The conventional vehicle has a 100+ year head start on the mass-market PEV.
There are millions of Americans who are considered early adopters and will do just about anything to have the “next big thing.” However, mainstream car buyers are more risk averse to new technologies. PEVs will have to appear mainstream in all facets to make a real splash in the car market.
Other alternative drivetrains like hydrogen fuel cell vehicles (FCV) will reach the market in the next few years, but will face a considerable barrier – a lack of refueling infrastructure. They do not have the range limitation of an EV, as you can drive nearly 300 miles on a single tank of hydrogen, but they require a hydrogen refueling infrastructure that is almost nonexistent in the United States today. These vehicles also face similar challenges to PEVs, including high initial cost that will have to be reduced
Our report finds, though, that the car of 2035 could be remarkably different from today's cars - if Americans take action in the public square and the marketplace.
Citizens need to support public policies like fuel economy standards that push us away from oil. And consumers must embrace advanced technologies so that public policy, technological progress, and market success can be mutually reinforcing. In the end, the differences between today's cars and those of 2035 are up to us.
Nick Nigro is a Solutions Fellow