The question of whether Gwinnett County’s referendum to increase the sales tax by one percent to fund additional public transportation measures – including a MARTA rail line – may very well depend on heavy voter turnout on Wednesday.

And more precisely, the election could depend on whether enough younger, more diverse voters show up on Wednesday to help overcome the heavy early voting of the county’s white, older residents who tend to oppose the measure.

All involved with the issue initially agreed it would be a close vote, with most betting that it would be 51-49 in favor of passing. But, with a strong surge in early voting, the pendulum may have swung the other way. According to Georgia Votes, to a voting analysis site, just over 60 percent of early voters were white as of press time; 75 percent were over the age of 50.

Historically, this is the demographic opposed to any MARTA expansion. As CityLab recalled in an article last week, a similar vote in the 1970s was divided along racial lines, and proponents of the referendum hope that Gwinnett’s changing demographics will push it through. Of Gwinnett’s nearly 1 million residents, roughly 60 percent are black, Latino or Asian residents. More than a quarter of them are foreign-born and the county, once a staunch Republican stronghold, voted for Hillary Clinton over Donald Trump in the last election.

This will be the first time that this younger, more diverse population will have a say about public transportation, though. The last vote on bringing MARTA to Gwinnett County, the fastest growing county in the state, was in 1990, when 90 percent of the population was white.

Gwinnett County Transit currently consists of six local bus routes that run almost exclusively on a single end of the county, as well as five express routes to locations inside I-285. If the referendum passes, projects would include a rail line extension from the existing MARTA Doraville station to transit hub in Norcross, near Jimmy Carter Boulevard, as well as the addition of more bus routes and express commuter buses.