SAN FRANCISCO, Aug 20 (Reuters) - Alphabet's

Waymo said on Tuesday it had doubled its paid rides to 100,000

per week in just over three months as the autonomous

ride-hailing firm expanded its areas of service and allowed more

people to ride its robotaxis.

Waymo's expansion comes just a month after Alphabet said it

was planning a multi-year $5 billion investment in the company

even as autonomous vehicle technology continues to face

widespread skepticism, tight regulatory scrutiny and federal

investigations.

Waymo, which has about 700 vehicles in its fleet, is the

only U.S. firm operating uncrewed robotaxis that collect fares.

The company opened its service to everyone in San Francisco in

June without joining a waitlist while expanding its operations

in metro Phoenix. This month, Waymo extended services to the San

Francisco Peninsula and to certain parts of Los Angeles.

"People still think of autonomous vehicles as the faraway

future, but for more and more people they're now an everyday

reality," Chief Product Officer Saswat Panigrahi said in a

statement, adding that Waymo's expanded "deliberately" and by

"optimizing costs".

That is critical as competition for Waymo is expected to

intensify. Tesla CEO Elon Musk is expected to unveil

the electric vehicle market leader's delayed plans for its

robotaxi product in October.

Others in the race include General Motors' ( GM ) Cruise,

which is finding its way back to U.S. roads with safety drivers

after a major accident last year; Amazon's ( AMZN ) Zoox, which

is expanding testing for its vehicles built without steering

wheels and pedals; and China-based WeRide, which is seeking a $5

billion valuation from its New York IPO and got approval from

California to conduct tests with passengers.