SAN FRANCISCO -- Lyft and Uber’s ridesharing war is raging on in San Francisco, where the two companies are trying to undercut one another by slashing the prices of the carpooling services both launched last year. UberPool and Lyft Line, as the services are called, group together riders who are headed in the same direction into the same car, allowing them to split the cost of their ride.

Uber was the first to announce a price cut, taking to its blog on Thursday to let San Francisco riders know that all UberPool rides within the city would top off at $5. The startup -- which has raised more than $4 billion in funding -- also announced reduced prices for rides going shortly outside of San Francisco, including $15 rides heading as far south as San Francisco International Airport.

Just one day later, Lyft tried to one-up its rival by announcing an ultra-low-cost “Match MUNI” campaign designed to get riders to skip using San Francisco’s public transit system and use Lyft Line instead. Lyft customers who use the special code MATCHMUNI will be charged only $2.25 for Lyft Line rides that start and end in areas north of Cesar Chavez St. and east of Stanyan St. -- that includes rides downtown, the Financial District, North Beach and the Mission District.

Both company’s price cuts are for a “limited time,” but neither has said when exactly they will end. Fortunately for drivers, the two companies said they will continue to be paid based on normal time and distance rates.

The price cuts are just the latest example of the bitter rivalry between the two ridesharing startups. In the past year, the two companies have tried to poach each other's drivers, steal customers with price cuts, and even accuse each other of trying to disrupt the other’s system by making and canceling thousands of ride requests.