Cops in the US can also require you to show ID when asked. Technically they need reason/probable cause to do so, but in the last few years
they have come up with many ways (Excuses) to get around this issue. If you fail to show valid ID when asked, they can arrest you for failure
to show ID/comply with a lawful order. Should you start to argue and yell at the officer, they can also get you for Resisting arrest, or any of charges
they can think of. Once your arrested, then they can also search you and your car (Should you be in one) without a warrant, as your failure
to Show your ID or prove your Identity, could be based on other (criminal) circumstances. (Transporting drugs/Open arrest warrant/etc.)

Circuit City Customer Arrested For Failure To Show ID
Denver bus riders forced to show ID or risk arrest and prosecution

Heres the text of a Police Blotter - Link

QUOTE
Feb. 7 - Officer stopped a vehicle for weaving. Driver arrested for driving while license suspended and failure to show I.D. to a police officer.



Then theres also this story, complete with Video.
Arrested for failure to show ID and the Video

And its's not just the US and Germany:

QUOTE
66,241 fines for failure to show ID were handed out by the Dutch police last year, according to the research group MMI. It gathers data on abuse of the legal obligation to carry ID, which came into force in the Netherlands on 1 January 2005. Around half of those fined refused to pay, so they had to go to court. Or will have to go to court. A backlog has been building up. Adjusted for population size, 66,241 fines in the Netherlands is the equivalent of about 240,000 fines in the UK. Meanwhile, Dutch campaigners Geen ID are offering an insurance package against ID fines.
See http://www.geen-id.nl/