Lack of sleep: hired drivers (cab drivers, lorry drivers, etc) don't take enough rest, thereby contributing to deadly crashes at night.
Unsafe parking on high ways: During nights, often bikes and other vehicles ram into parked trucks in the middle of no where. These parked vehicles should leave some kind of flasher cones for 400 feet or so. Another result of bad driving practices, along with no traffic enforcement.
Auto-rickshaws (3 wheelers) and motor bikes (2 wheelers): whenever I hear about accidents in India, there is a 85% chance that these deadly vehicles are involved in accidents. These auto-rickshaws (esp during day time) just swerve at last minute on Indian highways. Either ban these vehicles on highways or build a special lane for these 2-, 3-wheelers.