SAN FRANCISCO (KCBS)— San Francisco taxi drivers are trying a new tactic in their war against shared car ride services like Uber, Lyft and Sidecar. They’ve taken to alerting insurance companies that the rival drivers may be committing insurance fraud.

As we’ve reported traditional taxi drivers are losing business to the startup companies who use private citizens driving their own cars to pick up fares who summon them with a mobile device app.

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Barry Korengold, head of the San Francisco Cab Drivers Association, is angry that the state only requires the new services to insure their drivers when they have a passenger, which means they’re covered only by their own, personal car insurance between fares.

Korengold believes few of the drivers tell their insurance companies they are using their vehicles for commercial purposes, which is why his cabbies are photographing every Uber and Lyft car they see.

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“We have collected over 3,000 different license plate numbers of these vehicles,” Korengold said.

And they’re sending them to the insurance companies.

“All of these drivers are committing insurance fraud. If you ask any one of them if they’ve told their insurance companies what they’re doing, you get a blank stare.”

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KCBS tried to ask three different Uber drivers about this issue, but they wouldn’t talk about it on tape.