The Republic Day Chief Guest normally travels with the President of India in his car from Rashtrapati Bhawan.
Obama, along with wife Michelle, was received by Vice President Hamid Ansari and his wife Salma, Prime Minister Narendra Modi and Defence Minister Manohar Parrikar.
President Pranab Mukherjee arrived soon after.
Since 2012, the President of India travels in a heavily armoured black Mercedes Benz S600 (W221) Pullman Guard. The armour is designed to protect against military rifle shots, bomb shrapnels and other explosives.
The Beast, based on a Cadillac DTS, is the first Presidential limousine not to have a specific model name.
Obama is the first US President to be chief guest at India’s