Auto Insurance Claims: Accident liability, disinterested witnesses, exit ramp

Question
Hi.  Had a MVA today and can't figure out who's legally at fault (in MA).
Traveling on a 3 lane highway.. I was switching lanes into the exit lane to take the next off ramp.  The person in the exit lane (which was also the same marked lane from the last ON ramp) decided to merge onto the highway lane 1. (I assume he was checking behind him to see if he could merge safely and accelerated.  His front driver's quarter panel contacted with my passenger side rear bumper and turned me sideways - I recovered control and pulled up just past the exit.  My question is who is at fault... He claims he was in Lane 1 travelling and not even in the merge/exit lane but my skid marks and where we contacted on the cars...says different as the skid marks were in the exit ramp's lane.

Answer
Hi Jason,
I am extremely familiar with that type on/off ramp common lane and can mentaly picture every one within a 60 mile radius  that I use on a frequent basis and always use extra caution when I have to use one of those ramps.
Since it serves as a lane for traffic merging in both directions, no one actually "owns" controll of that lane.
Without a police report or disinterested witnesses, it usually becomes a case of "I said, he said", and is usually settled on a 50/50 basis.  Your insurance company may decide to do an 'on scene'
anylisis and diagram  of the accident and measure the skid marks and fight for a different split such as 30/70 or 40/60, but is highly unlikely that either one of you can be found 100% at fault.

Make a report to your insurance company and let them deal with the fault issue.

I hope that you have found this information to be helpful.
Your feedback by rating my answer will be appreciated.

Sincerely,
Bennie
San Francisco Bay Area