Will electrified vehicles dominate our highways in the future? It’s a question on the minds of many these days as an increasing number of battery electric and plug-in hybrid models come to new car showrooms. The answer is not an easy one, especially since there’s the potential that future CAFE (Corporate Average Fuel Economy) requirements could be modified. CAFE has been a driving force in the accelerated research and development in plug-in vehicles and new model introductions.

Automakers as a whole have said the current CAFE requirement of 54.5 mpg by 2025 cannot be achieved without a serious emphasis on electrification and the efficiencies these models bring. Thus, there has been an undeniable momentum for plug-ins underway as witnessed by the 39 battery electric and plug-in hybrid models from 20 automotive brands available in the U.S. market during calendar year 2017.

It has been a long path to get to this point since modern electrics emerged in the early 1990s. Along the way, early battery electric vehicles have been constrained by the limitations imposed by the very nature of battery electric propulsion. Simply, batteries are very heavy and costly, which result in two distinct penalties – greater weight that saps overall efficiency and high production costs that either make these vehicles expensive to buy, or require automakers to absorb much of these costs.

Those were the issues in the 1990s and, not coincidentally, these remain the issues today. Battery electric cars in 2017 are an order of magnitude better than those of a few decades back. But driving range and cost remain significant challenges. Plug-in hybrids are another matter.

Since these offer both all-electric driving and hybrid operation after batteries are depleted, there is no ‘range anxiety’ – the concern that a battery electric vehicle’s battery power could be insufficient for daily driving needs. Automakers are into plug-in hybrids in a big way and this has become a very competitive part of the automotive landscape.

So what does our driving future hold? There are nearly 40 plug-in vehicles for sale this year and that’s a big statement. Most major automakers have thriving electric research and development programs underway with electric model launches of one type or another in the pipeline. We will see an expanding offering of plug-in hybrids with battery electric models featuring greater driving range, as witnessed by the benchmarks being set by Chevrolet and Tesla and the new commitment to electrics by Volvo.

One wild card is that internal combustion continues to achieve surprising efficiency gains, at reasonable cost compared to electrics. That means the combustion vehicles we’ve had on our roads for more than a century will continue to ply our highways for some time to come, at approachable cost and without the need for the federal and state incentives that now help motivate buyers to go electric.

Still, there’s a growing desire for the emissions and inherent efficiencies of electric drive so there’s every reason to expect this interest to increase. We don’t yet know if plug-in vehicles of one stripe or another will dominate the market in the years ahead. But what is clear is that electrification is poised to play a major role moving forward.

There are many outspoken and polarizing proponents of the various fuels and technologies at play today. This has been the case for several decades now and isn’t likely to disappear anytime soon. Many electric car enthusiasts do not see a future for internal combustion or even hydrogen fuel cell vehicles. Hydrogen proponents point out that fuel cell vehicles make more sense than battery electrics since hydrogen generally offers greater driving range and fuel cell vehicles can be refueled in under five minutes, while battery electrics cannot. Biodiesel enthusiasts point out the obvious benefits of this biofuel and even as this fuel gains momentum, wonder why support isn’t stronger. Natural gas advocates see huge and stable supplies of this clean-burning fuel now and in our future, without the truly significant commitment to natural gas vehicles this should bring. And those behind internal combustion vehicles achieving ever-higher efficiency simply wonder what the fuss is all about when conventional answers are here today.

So in the midst of all this, where are we headed? Simple. In the right direction, of course.

As I was writing about these very fuels and technologies some 25 years ago, it wasn’t lost on me that the competition for dominance in the ‘green’ automotive world of the future would be hard-fought and long, with many twists and turns. As our decades-long focus on the ‘green car’ field has shown us, the state-of-the-art of advanced vehicles in any time frame is ever-changing, which simply means that what may seem to make the most sense now is likely to shift, and at times, shift suddenly. This is a field in flux today, as it was back then.

When Nissan powered its Altra EV back in 1998 as an answer to California’s Zero Emission Vehicle mandate, it turned heads with the first use of a lithium-ion battery in a limited production vehicle, rather than the advanced lead-acid and nickel-metal-hydride batteries used by others. Lithium-ion is now the battery of choice, but will it remain so as breakthrough battery technologies and chemistries are being explored?

Gasoline-electric hybrids currently sell in ever-greater numbers, with plug-in hybrids increasingly joining their ranks. Conventionally-powered vehicles are also evolving with new technologies and strategies eking levels of fuel efficiency that were only thought possible with hybrid powerplants just a few years ago.

What drives efficiency – and by extension determines our future path to the high efficiency, low emission, and more sustainable vehicles desired by consumers and government alike – is textbook evolution. Cars are adapting to meet the changing needs of future mobility and the imperative of improved environmental performance. Some of these evolutionary changes are predictable like lightweighting, improved aerodynamics, friction reduction, and enhanced powertrain efficiencies. Other answers, including the fuels that will ultimately power a new generation of vehicles, will be revealed over time.

So here’s to the cheerleaders who tell us quite vocally that their fuel, technology, or strategy is the answer to our driving future. One of them may be right. But the fact is, the evolutionary winner has yet to be determined.