The victim, R Yadav, is posted in Noida.
Last night, Yadav was riding his motorcycle when a speeding dumper hit it. He was critically injured, they said.
Yadav was rushed to a hospital where a portion of his leg had to be amputated, they said.
An FIR has been lodged against the driver of the dumper at Sector 49 police station.
The accused was, however, not traceable till late evening today, they said.