When it comes to getting around Boston on four wheels, there’s an app — apps, actually — for that. The question, in this competitive and fraught market, has become: which one should you use?

The list of options was set to grow by one this week, as ride-hailing underdog Lyft announced a new service called “Lyft Line,” offering carpoolers discounted rides – for $7 or less to start, provided they’re heading in the same direction and have destinations in a Lyft-approved zones (Harvard Square to the South End, Allston to the North End). It launches in Boston on Thursday.

RELATED: Uber launching water taxi service

But lots of companies are doing the same thing.

Uber launched a similar carpooling service in August, called “UberPOOL.” Sidecar, the least known of the three, has one, too: “Shared Ride.”

The Lyft announcement comes as changes brew in Massachusetts to the ride-sharing scene.

The Legislature is mulling new rules for ride-hailing companies, which could tighten requirements for insurance, background checks, among other provisions.

RELATED:   Braintree halts ride-hailing crackdown

And Boston cab drivers, who’ve seen their business crippled by smartphone-enabled services, plan to welcome the launch of a cab-friendly app sometime soon: Way2ride. The app, by Californian e-pay company Verifone, is live in New York, and the company said on its website it would launch in Boston and three other cities before a nationwide rollout in all U.S. Verifone markets in 2016.

Uber is already doing its own version with "UberTAXI."

Outside Boston, there are other apps to watch that hook riders up with old-fashioned cabs.

RELATED: Uber and Lyft opponents push for more ride-share regulation

Remember Hailo?

Remember Hailo?



For example, here’s a name you may not have heard before: Flywheel, another taxi-hailing app that isn’t in Boston but is active in cities on the West Coast. Curb, a similar company, operates in 60 cities, but again not in Boston.

But the battle for dominance in ride-sharing is never over because new tech in the industry isn't a sure thing

Remember Hailo, the London-based service connecting riders to cabs? It pulled out of North America in 2014, saying it couldn’t compete.