As long as he/she is not busy dealing with someone else you can ask. Just say, "Excuse me, but can you help me? I need directions." and then tell him/her where you want to go.
If a cop is stopped in a parking lot, is it wrong to ask for directions? How do you approach them to ask
Of course not, as long as he's not busy. Race or sex doesn't matter. Just start walking over to them, wave your hand and make sure you look like you need to ask them something. Be sure you make them aware you have a question before you get to the car so as not to frighten them.
If it's an emergency. If there are other options I would go with that. If you were completely lost, late at night, no gas stations or no map to get directions, then yes.
Out of laziness or convenience, no. Asking a police officer for directions would be my last resort.
My best friend comes from a police officer family. Unless it pertains to their job in some way, they didn't like to be bothered. Even though they might be parked in a car, you never know what they could be doing. If however they were standing around talking then we would talk to them. If they were on the job, no I wouldn't bother them.
I remember a bunch of times sitting in a car next to her family member(s) and they wouldn't even acknowledge us in the car because of concentrating on their job. They are listening to dispatch, looking things up on the computer, observing cars and people behaviors around them and driving. I wouldn't want to disturb that process for directions.
Also when addressing any law enforcement always use "sir" and "ma'am".
Sometimes how you approach successfully depends on your race, culture, or ethnicity. Some police are having increasing concerns about dealing with the public in light of what has been happening to them.
You would ask them just like you would ask anyone .. "Can you help me, I'm lost" .. Or "I'm looking for ??? Street".
Never any harm in asking .. If they can help they will, if they can't they will tell you where to get help. No need to be afraid to ask.