Police Sergeant Mostafa Abdel Haseeb shot driver Mohamed Ismail, 25, in the head following the dispute in February.
He can appeal against the verdict issued by the Cairo criminal court.
The shooting fuelled public anger over alleged police brutality and lead to protests at the city's police headquarters.
The anger over the incident prompted Egyptian President Abdel Fattah al-Sisi to announce a crackdown on police abuses.
Other high-profile cases include accusations that police officers beat two doctors at a Cairo hospital for refusing to falsify medical records.
And in February the body of a missing Italian graduate student was found on the outskirts of Cairo showing signs of torture. Activists said that Giulio Regeni's injuries bore the hallmarks of the Egyptian security services. The interior ministry denies any involvement.
Anger over perceived police excesses helped fuel the 2011 revolt that began on a Police Day holiday and ended with then-President Hosni Mubarak stepping down after 30 years in power.
An Egyptian policeman has been sentenced to life in prison for shooting dead a Cairo rickshaw driver during an argument over a fare.