Diyyat & Expiation

Aslam O Alaikum I have a question which I shall be highly thankful if you can please answer it. A few months ago, I along with my Wife and Daughter were going on a Motor Bike. While taking a Uturn on Road, a Motor Bike hit us. I sustained injuries and so did my Wife and daughter and the other person who hit us. However, my wife could not survive injuries and died. Now about accident, as per the witnesses on the road the other guy was at a high speed on a link road and he because of the speed he could not handle his bike when we came in front of him. As for me, I did look at the road while taking Uturn and could not see anything as long as my eyes could see. However, my mistake was that I did not properly stopped on Uturn and I believe I could have averted the accident if I had stopped the bike and see the road entirely till end. So I believe that may be I was also at fault, I could have averted this accident by being more careful. Now my question is that do I have to pay the Diyyat for my wife's death and if yes then to whom as it is to be paid to heirs? Who would be her heir besides me? Also if I need to offer expiation as well? My wife died because of the mistakes by the Biker and possibly me as well. Please answer and oblige.