When a family was traveling in the night they met with an accident and with the grace of Almighty Allah escaped without hurt Al-Hamdu Lillah. Also, they give Zakah and Sadaqa. In order to thank Allah (SWT) can we give Sadaqa or sacrifice an animal? Kindly advise what we can do according to Qur'an or Ahadith (Please give reference).

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

No doubt, by only Allah's favor and blessing you were kept safe in this accident. So, you have to be thankful to Allah for this great blessing. The most important part of being thankful to Allah is following His Commands through practicing obligations; giving Zakah is one of them, performing as many voluntary acts as possible and avoiding prohibitions, leaving dislikable acts as much as one can.
Among the forms of being thankful to Allah is giving charity to the needy; feeding needy people is a form of giving charity and slaughtering an animal to feed them is in fact, a form of feeding. However, slaughtering is not an obligation.
You must renew your repentance toward Allah and should remind yourself of death. The Prophet (Sallallahu Alaihi wa Sallam) said: "Keep much in remembrance of cutter-off of pleasure, i.e. death" . [ al-Tirmizi and others].
Whoever frequently remembers death will be away from sins and will work for the Hereafter.
Allah knows best.