Mehra, 43, was on his way home in Geeta Colony from a wedding on GT Karnal Road on Monday, when he was fatally shot by one of the occupants of the other vehicle which scratched his car, after he cautioned them to drive carefully.
Mehra was accompanied by his minor son when the incident happened.
During the meeting with Delhi Police Commissioner Amulya Patnaik, Maken demanded police protection for Mehra's son.
Mehra's father Mangat Ram, brother Pramod, and the minor boy also met police commissioner Patnaik, along with Maken.
The Congress leader expressed concern over the increasing road rage incidents in Delhi.
"Road rage has become a major threat on Delhi roads and if such people are allowed to roam freely with firearms, then we must think where this city is headed," he told reporters after meeting the police commissioner.