Question about No Parking signs rule that I never heard mentioned

When it comes to a no parking sign, how far do you have to be away from it in order to avoid being in violation? Can it be 15 feet in front of you and not be a violation? I am not sure if the sign has to be next to your truck to qualify.

 

Yeah I never park next to a fire lane or hydrant, but right now at this Walmart they have wide shoulders where trucks are parked and one part had a No Parking sign on the shoulder. I parked there for five minutes to send a message and the No Parking sign began about 15 feet in front of me and the space beside my truck and trailer had no signs. I went ahead and moved to another spot just to make sure. Even though I know those signs are never enforced lol, I just want to make sure. I have no idea if the sign needs to be beside your truck or if there is a certain amount of feet in front or behind the sign to be in violation.

 

Sorry I mean a Walmart DC not a store. There are a whole line of trucks here as this is one of the rare Walmart DCs that has parking. So no one really knows how far you can park in front or behind a no parking sign? Yeah there were times when I had to park at a Walmart store and I always park behind near the loading dock and no one ever says anything. I wouldn't be surprised if they think that I am supposed to be there.

 

If it is OK can anyone please just answer my No Parking distance question? I am sure all of us had to wonder how close is too close when you are almost out of hours and see a spot available and there is a No Parking sign 20 feet away.