DETROIT — As transportation planners gear up for a tax request for regional transit next year, debate is percolating about how the explosion of mobility options could influence the vote.

The Regional Transit Authority of Southeast Michigan by January is expected to call for a multibillion tax request to establish express bus lines along major roads, commuter rail service from Ann Arbor to Detroit, airport express lines and rapid bus transit along Woodward Avenue.

Transportation options, though, have skyrocketed since a similar plan was defeated in 2016 by voters in Oakland, Wayne, Macomb and Washtenaw counties. In the past two years alone in Detroit, companies have introduced about 1,000 electric scooters, a bike-sharing system used for 237,000 rides last year and a driverless shuttle system in downtown.

Add in the popularity of ride-sharing services such as Uber and Lyft – and the prospect of self-driving cars hitting the market in the next decade – and some question how the technology will influence the bond request that’s expected to be for $4 billion or $5 billion over the next 20 years.

To transit skeptics, paying big money for regional transit amid fast-changing technology is akin to investing in buggy whips at the dawn of the 20th century. But advocates say the so-called new mobility will complement, not replace, traditional mass transportation.

“There is no silver bullet,” said Megan Owens, executive director of Transportation Riders United, a Detroit-based nonprofit that advocates for transit improvements.

“People always want to oversimplify the issue, and say that autonomous vehicles are going to save us all. Not necessarily. If Uber is any example, the result has been more congestion and more pollution in some of the biggest cities. All of these different pieces work best when they complement each other.”

The discussion comes as RTA leaders continue talks with government officials about when to seek a tax and whether such the request will cover all four counties. Last year, a lack of support from Macomb and Oakland counties killed the $5.4 billion, 20-year Connect Southeast Michigan plan that would have been repaid through a 1.5-mill tax.

In Oakland, the tax is viewed more favorably by government leaders following this year’s death of Executive L. Brooks Patterson and appointment of his interim successor, Dave Coulter, a transit booster.

Resistance remains in Macomb County, whose Executive Mark Hackel has long questioned whether his taxpayers get value from transit and last year’s tax renewal for the SMART bus system passed by only 39 votes.

“You can’t push that square bus peg through the round hole in the suburbs. It doesn’t work,” said Macomb County Commissioner Leon Drolet, founder of nonprofit Michigan Taxpayers Alliance.

In an opinion column this fall, Drolet wrote “Detroit would be foolish to waste resources on a dying transit model.”

Last year, Drolet proposed scrapping SMART’s fleet of buses, instead tasking the agency with issuing subsidized transit cards redeemable for Lyft and Uber rides.

Like almost all transit systems, SMART requires a hefty subsidy: Fares comprise just 10 percent of its $127 million budget, records show.

“We do have a transit system that works for the great majority. It’s the car,” said Drolet.