What is the max benefits you can receive from rear end accident?

The most you are entitled to is your provable, actual out-of-pocket (not paid by insurance, Medicare/caid, etc.) medical costs, including sufficiently provable future costs; lost wages, if any; provable future diminished earning potential, if any; and if the injury has caused significant life impairment, some amount for "pain and suffering," though that latter is very subjective and hard to quantify; it is generally approximately related to your medical costs, so the greater the medical costs, usually the larger the pain and suffering award. This all together is the most you can get from the sum of insurance and the other party (the other driver personally), though you may well have to sue for this money if it is not voluntarily paid to you by insurer and/or other driver. Obviously, what you can get as a practial matter is limited by insurance coverage (an insurer only has to pay up to policy limits) and the amount of money and assets possessed by the at-fault driver: it is possible that with serious injuries, that the compensation to which you might be entitled exceeds the available insurance and the money which the other driver has, in which case you will only recover part of what might otherwise be coming to you.