Mark Campbell loves using Car2Go but sometimes finds the tiny Smart cars that make up the company's entire fleet in Calgary to be a little limiting.

"There's been a couple of times I've wanted to take a Car2Go with some friends to some place but if we had three people we'd either have to find two Car2Go or find another way to go," he said.

So when Campbell spotted a truckload of Mercedes B200s bearing Car2Go logos arriving in Calgary earlier this week, it caught his attention.

The Calgary engineer tweeted at the company to inquire about the five-passenger vehicles, which are similar to the ones it uses as part of its "Car2Go Black" premium service in Germany, and he was encouraged by the reply from the @car2goCalgary account.

"They said it looks like they were getting some sort of siblings and to stay tuned for news," he said. "So it's exciting."

Numerous Car2go-branded Mercedes vehicles outside a dealership in downtown Calgary. (Stephanie Wiebe/CBC)

Car2Go says it expects to make an announcement as early as Monday.

A spokesperson declined to answer questions from CBC about the new vehicles, which are now being stored at a Mercedes-Benz dealership in downtown Calgary. Daimler AG produces both Mercedes-Benz and Smart cars, and owns Car2Go.

The tweet in reply to Campbell's question was later deleted, but speculation had already begun online that the company's existing 550-vehicle fleet of Smart cars in Calgary is soon to be augmented with the larger, more luxurious vehicles.

Tiny Smart cars like this one make up all of the current 550-vehicle car2go fleet in Calgary. (CBC)

After launching in July 2012 with just 150 Smart cars, Car2Go has expanded rapidly in Calgary.

Its membership has swelled to 80,000 people in the city, making Calgary the second-largest market for the one-way car rental service in North America behind Vancouver.

Earlier this year, Car2Go recorded its two-millionth trip in Calgary.

Taylor Olson doesn't use the service often — just once every couple of months — but said she finds it useful for specific purposes.

"Sometimes I would feel a little too lazy in the morning to walk myself to the bus stop," the Calgary resident said. "Or it's great for going out downtown and taking it as a one-way transit option to go out bar-hopping and then find a taxi later."

A closer view of the group of Car2go-branded Mercedes parked outside a downtown Calgary auto dealership. (Stephanie Wiebe/CBC)

Olson doubted the new Mercedes cars would change her own Car2Go usage, but said the city could certainly use more transportation options.

"Given the terrible parking situation in Calgary downtown, and the lack of taxicabs, I think it's great (if) they're expanding — so I welcome that change," she said.

Campbell said the Mercedes vehicles would be better for transporting larger groups of people or goods, and would come with another benefit too.

"They'd be a lot more fun to drive than the regular Car2Go," he said.