Anthony Joseph, 55, and his wife Sagai Mary, 52, were on their way home on their scooter with their six-year-old granddaughter from St Johns Hospital, where they had taken her as she was running a fever.
On Mysuru Road flyover, Mr Joseph applied sudden brakes on seeing a huge pothole and lost control of the two-wheeler.
A speeding bus of the Tamil Nadu Road Transport Corporation coming from behind hit their vehicle, killing them on the spot. The bus driver fled from the accident site, police said, adding they have seized the bus and have sent out teams to look for the driver.
After the accident, the opposition BJP in Karnataka criticised the government for allegedly not improving the roads in the state. BJP leader NR Ramesh alleged there was a large-scale "road repair scam" in the Congress-ruled municipal agency Bruhat Bengaluru Mahanagara Palike.