Asked in 2018 to pay for a transportation overhaul that would include a new light rail system and a downtown tunnel, Nashville voters bluntly said no.

Six years later, as the city bursts with thousands of new residents and worsening traffic, Nashville leaders are trying again. This time, however, they are focusing on the barest of basics: new buses and routes, more sidewalks and the synchronization of traffic lights, all for the price of a half-cent county sales tax increase.

It is still unclear whether it will be enough to persuade voters.

The modest ambitions of this referendum underscore the reluctance of voters to pay for infrastructure improvements, even in a car-centered city struggling to keep pace with explosive growth.

“This is how we catch up on a generation of underinvestment,” said Mayor Freddie O’Connell, a Democrat who has spent much of his first year in office pushing the transportation improvements.

“Plan B is realistically the status quo,” he added.

The vote, carefully timed to the higher turnout of a presidential election, pits the city’s deeply ingrained aversion to tax increases against a palpable frustration with its poor infrastructure. It also comes at a critical moment, when Nashville is competing against bigger and more developed cities for a rare influx of federal money.