The incident took place at around 11 AM, when one Sanjay was going with his family towards Kharkhoda in Haryana.
"When they reached near Kanjhawala, their car suddenly hit a roadside tree seriously injuring the family members" said a senior police official.
All of them were rushed to hospital, where Sanjay (35), his wife Sangeeta (26), son Abhishek (5) and brother Sonu (30) were declared brought dead, he said, adding, rest five are recuperating from their injuries.