LISBON — Residents of this port city of faded beauty and ornately tiled facades have welcomed a surge of tourists in recent years who have helped turn around its economic slide.

But the foreign visitors, they will tell you, have also come with their share of trade-offs. Rapid redevelopment, spurred by tax breaks granted to foreign property buyers, has driven up rents and widened disparities. Streets are more crowded, the traffic worse.

And then, there is the tuk-tuk.

In just a couple of years, about 300 of the motorized, three-wheel vehicles have swarmed Lisbon’s narrow cobblestone streets, offering tourists an alternate way of navigating this hilly city, famous, too, for its network of trams and funiculars.

While visitors have flocked to the tuk-tuk, those who live in this city of about 550,000 have begun to fume about pollution, noisier streets and a verging “quality of living problem,” according to Miguel Gaspar, a Portuguese transportation consultant.