What if you actually have been drinking? Maybe you had one beer with dinner; you’re not exactly driving under the influence, but if you say no, then you’re lying to the cop. Maybe your not-so-savvy wife or kid in the car with you says “what about that beer you had with dinner,” and suddenly you may have a major legal problem.
If the cop is asking you questions that could incriminate you, you don’t need to insist on consulting a lawyer - you can simply refuse to answer such questions at all.
“Have you been drinking tonight?”
“Sorry officer, I’m not going to answer that.”
“What are you doing over here in [an area far from your home that’s known for drug activity]?”
“Sorry officer, I’m not going to answer that.”
“Are there any illegal drugs in your car?”
“Sorry officer, I’m not going to answer that.” (don’t say no, because if your passenger stashed some weed under the seat, you could have a problem)
“Do you mind if I search your car?”
“Sorry officer, I will not consent to a search of my car.” (this should always be your answer no matter what you believe is or is not in your car; your beliefs may be incorrect)
“Is there any particular reason you won’t consent?”
“Sorry officer, I’m not going to answer that.”
“I can detain you here until the drug K-9 arrives to inspect your car.”
“Acknowledged.”
Now he has to decide if he should waste everyone’s time with what may be an unproductive K9 search. If you’re lucky, he won’t - or he will, but the dog won’t find anything. But you don’t help yourself by confessing upfront, consenting to a search, or lying in an attempt to avoid being arrested.