July 10 (Reuters) - Tesla reached out to

Arizona late last month to start a certification process for an

autonomous vehicle ride-sharing service, and a decision is

expected by the end of this month, the state's transportation

department said on Thursday.

"They have expressed interest in operating within the

Phoenix Metro area," Arizona's Department of Transportation said

in an email to Reuters. Tesla has applied to test and operate

both with and without a driver, it said.

Tesla last month

rolled out a small test

of its robotaxi service in a limited area of Austin, Texas,

with about a dozen vehicles, a select group of passengers and

many restrictions, including a safety monitor in the front

passenger seat.

Even as social media videos showed

multiple traffic problems

and driving issues over the first few days, CEO Elon Musk

said on Wednesday that Tesla would

expand the service

to a larger area in the city this weekend and, depending on

regulatory approvals, to the San Francisco Bay Area within two

months.