I was referring to street traffic too. And you still dont have whats referred to as "right of way". If you're turning left acrost traffic into a parking lot & someone is turning left out of it. Then you have "right of way". If you're an ocean liner & are sharing a bay with a dingy, then you have "right of way". You dont have to allow someone to merge in front of you. But it's considered bad form not to.
You dont actually have to stop to let someone over btw, maybe thats your issue. You can just slightly depress the break pedel for aprox 2 seconds.
However, if they need to get over and say, turn at the next cross street? They will need to stop if no one lets them in, and they often do. Which often does cause accidents. Unlike yeilding to someone trying to merge, which is generally considered good driving habit & proper etiquette.