A question about merging

Arizona

I would like to know what aspects would be used to determine fault or liability if two cars should merge into the same lane at once and collide.

This is not a question about a past situation. I would just like to be well informed as near misses of this nature occur in my city, Phoenix, on a near daily basis and I am a firm believer in Murphy's Law. We have highways with at least three or four lanes (and more!) in each direction and traffic flows that have to cross through each other. Drivers often take an available hole from the opposite side of the lane as another driver who is also trying to take it. They do this very quickly as many Phonician drivers drive according to "I'm not tailgating, I'm drafting!" so holes are a rare and valuable occurance.

The only thing I can think of is if one of the drivers failed to signal. However, that would be a he-said-she-said by the times the cops arrived. Does anyone have any experience pertaining to this?

[racer72]

Except for instances when the vehicles on the right have signs to yield to the flow of traffic, the vehicles on the right always have the right of way.

Thank you, Racer. That is helpful.