A recent study from the University of California, Davis suggested that awareness of available plug-in electric cars among potential buyers was no higher in 2017 than it had been in 2014.

Worse, only California car owners were surveyed—and that's the state in which roughly half of all the battery-electric and plug-in hybrid vehicles in the U.S. have been sold.

The report should be a wakeup call for electric-car fans, advocates, and drivers.

DON'T MISS: What if car buyers aren't ready for electric cars, even in California?

It highlights the uncomfortable truth that there remain huge hurdles before even a substantial percentage of mass-market car buyers will be willing to consider electric cars.

UC-Davis research has previously shown several different motivations for buying a plug-in car, from early tech adoption through environmental concerns to sheer cost-saving over the lifetime of the electric vehicle.

But we wanted to see what our Twitter followers thought would be the most important issue that would get the the rest of the U.S. over the hump.

Our latest Twitter poll offers four choices for what will get more buyers to consider buying a plug-in electric vehicle over one that runs only on gasoline.

We know that all of them will play some role, of course, but the poll is set up to allow only one choice—the one participants feel will be most important.

READ THIS: Car buyers have no idea electric-car charging stations even exist

First is lower prices for plug-in cars, the sticker price (or monthly payment) being perhaps the most important factor in selecting which vehicles buyers will even consider.

Then there's marketing and promotion, specifically by carmakers. As readers of this site, you may well have seen ads for plug-in cars, but we can guarantee you most U.S. drivers never have.

Tesla Supercharger for city centers

Tesla Supercharger for city centers

Another option is more public charging. Survey after survey shows that the general public has no idea that electric cars can already be recharged at tens of thousands of public stations today, because they don't see them and they're virtually never signposted.

The last choice is the environmental benefits that accrue from driving on grid electricity, which by this point are well-established and hardly in debate.

CHECK OUT: Plug-in hybrid problem: buyers don't understand them at all

We have our suspicions as to what survey participants will choose, but we'll save those for next week's report on the actual results. Vote now!

As always, please note that our Twitter polls are far from scientifically valid, due to small sample size and self-selection by those who choose to participate.