  The recent type Ia supernova data suggest that the universe is accelerating
now and decelerated in recent past. This may provide the evidence that the
standard Friedmann equation needs to be modified. We analyze in detail a new
model in the context of modified Friedmann equation using the supernova data
published by the High-$z$ Supernova Search Team and the Supernova Cosmology
Project. The new model explains recent acceleration and past deceleration.
Furthermore, the new model also gives a decelerated universe in the future.
