State Fish and Wildlife deputy director Lawrence Herrighty says it's the beginning of breeding season when male deer start chasing does.
Herrighty says deer are most active during dawn and dusk.
The Highway Loss Data Institute and wildlife officials say collisions increase in late September and peak in November.
The state Transportation Department removed 6,028 deer carcasses from roads in 2009.
State Farm Insurance told The Star-Ledger of Newark that Garden State motorists face a "medium risk" for hitting deer. The odds are 1 in 183 compared to Pennsylvania, where the odds are 1 in 85.