At Green Car Reports, we've developed something of a tradition for Earth Day. Back in 2014, we formulated the question: "When will we start to see tailpipes on cars as morally wrong?"

The question came originally from a friend who works in advocacy in public health, who likened CO2 emissions from tailpipes to smoking cigarettes, which has now been frowned upon in many circles for decades.

MUST READ: An Earth Day question: When will we see 'tailpipes' on cars as morally wrong? (2015)

For Earth Day 2019, which happened April 22, we revised the question somewhat to ask: "When will it be socially unacceptable to drive a car with a tailpipe?" Not all readers are that judgmental, but society can be. 

As electric cars have advanced more quickly than some anticipated, we also changed up the answers somewhat to gain insights into readers' thoughts given the current state of the market.

Many of this year's poll respondents, 23 percent, said it is already socially unacceptable to drive a car with a tailpipe. At least in their circles, apparently. That was the second highest number of responses in this year's Earth Day poll.

Most respondents were somewhat more sanguine—or pessimistic depending on your perspective. The largest number of respondents, 44 percent, chose 2030 as the tipping point. That jibes with forecasts of when a wider variety of electric cars will be available and after electric cars are forecast to achieve price parity with gas-burners.

CHECK OUT: When will it be unacceptable to drive a car with a tailpipe? Poll results (2017)

Slightly fewer respondents than those who already find it unacceptable thought it might take longer, until 2040 or later, for society to make such a switch: 21 percent. Perhaps consider them realists deferring to the legions of poorer people who may not be able to afford a new car and for whom a practical electric car may not trickle down to the used car market for a while yet.

Another 11 percent, the fewest in our poll, said it might never be socially unacceptable, perhaps either taking the libertarian viewpoint, or seeing a need for some form of combustion vehicles well into the future.

Despite the changes to the question and the possible answers, the results hewed fairly closely to those from the last time we ran a new version of the survey, in 2017. Then, 26 percent chose 2025 as the year tailpipes will be unacceptable; the largest majority of 37 percent said by 2035; and 19 percent by 2050. The biggest change may have been the larger 18 percent who thought tailpipes might always be OK. Perhaps that's the biggest sign of progress on electric cars for Earth Day 2019.