Lyft will roll out Line service to 6 new cities, including Seattle and San Diego

Expect a new boom in low-cost ride-sharing: Lyft announced today that it will roll out its Line option to six new cities over a five-day period. By April 15, Lyft will have Line in 15 cities total, serving 25 percent of the U.S. population.

Starting on April 11, Line will come to Denver, Philadelphia, San Diego, San Jose, Seattle, and Newark. So if you’re traveling to those areas, you’ll now be able to get a ride at a 40 percent discount if you share with another rider.

Line makes up for almost 40% of total rides in communities where it’s available, so it’s not surprising that the option will be headed to what Lyft considers its fastest-growing cities. The more incentive a rider has to take a car over driving themselves, the higher likelihood a car will be called.

It’s also a tactic Lyft can take to exert a little more dominance over Uber in small cities. To date, Uber’s similarly-functioned Pool service runs in 15 cities nationwide — but none of the cities where Line will be expanding. That might give riders a big push to pick one over the other in rapidly growing markets.