See, this is one of the reasons I hate passing through PA (darn mountains being the other) - them DOT idiots plop a stop sign right where the on-ramp meets the interstate, so ya'll are supposed to floor it and in three seconds reach 60-70mph. About anywhere else I drive there ain't no retarded stop signs like that, and you actually use the on-ramp to accelerate enough to match speed with the main traffic on the interstate and merge nice and easy.
Actually the accident was technically your mom's fault, maybe not to the police but most insurance agencies just automatically assume that the moment you rear-end someone it's your fault - I went through this years ago, lady suddenly changed lanes right about a foot in front of my bumper and immediately got on her brakes, I stood up on mine the moment she got in my lane but it was too late as her car apparently had better brakes than mine. According to the book it should have been my fault as it was me who hit her, however cops wrote it up as a no-fault as it was her who whipped in my lane with no warning and leaving me no time to react - no points on my driving record and oddly enough my insurance didn't go up either, but my insurance company did have to pay for her vehicle to be rebuilt (whereas I spent only a bit over $100 in parts and one day of my weekend and was good as new).
You gotta consider what some people do these days tho, them insurance scams - their own POS econobox has some major mechanical issues that can only be fixed with OEM parts (very common with newer imports) the cost of which together with labor add up to more than what the car is worth, one day while driving they see this big nice and shiny truck behind them and figure the owner must have good insurance on it, so good in fact that it would pay not only for the truck but also for any vehicle that happens to be involved in an accident with it - brake stand, here we go!!!
I was actually with a friend in her dad's F600 hot-shot (all chromed out and lit like a Christmas tree) when some jackwagon decided to pull that one, there was no one else but our two vehicles on the on-ramp and just before he gets on the interstate the SOB just stood on the brakes for no traffic-related reason whatsoever - well an F600 don't stop as fast a small car, my friend managed to slow down good but still hit him. Then proceeded to kill her lights (so he has no chance of seeing the plate), push him out the way, and get the heck outta there as fast as she could - she said she ain't getting punished for someone else's stupidity, and IMHO she was right - she's a pretty darn good driver, but there's only so much she can do when someone is deliberately playing hard against her...
. Wheel arch trim was a little dented but it's a farm truck so what the heck.
Just kidding; I know you are smarter than that. 
