system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do the police in the US have you do several tests to determine alcohol consumption instead of using Breath tests?

In most european countries police will just have you blow into a device that then shows your exact alcohol level. 
Judging from movies and other media, in the States the Police use physical tests (touch your nose, walk on a line) instead. Why is that? Is this a false demonstration in media or is there some reason they do not use these devices?
gpt
Police actually do use those tests in the US (we call them sobriety tests). The reason is that you can refuse a breathalyzer test, but police still need evidence to show that you're drunk (the tests are usually filmed by the police car's dash cam). You can also refuse the sobriety tests, but a lot of drunk people think that while a machine will give away their drunkenness, they're not so drunk that they'll fail to touch their nose (they usually are too drunk to pass, but drinking increases confidence).

What happens if you refuse the breathalyzer depends on the state, but in Texas you automatically lose your license and will almost certainly be arrested for drunk driving. However, most lawyers still recommend that you don't blow into the breathalyzer because if it's above the legal limit you'll probably screwed at your trial.

tl;dr - Police use those tests because people can refuse the breathalyzer, even though there may be consequences for doing so, and the police need evidence that the person is drunk. People can also refuse to do the tests, but they often don't.