The two certainties in life — death and taxes — may be more intertwined than Ben Franklin ever imagined: A study found that deadly auto accidents increase on Tax Day. Drivers recklessly racing to the post office to meet the deadline might be one reason. Or it could be that stressing over taxes distracts motorists and contributes to human error, researchers said. They looked at 30 years of data and found 6,783 traffic-related deaths on Tax Day, or 226 per day. That compares with 213 per day on one day a week before the deadline day and another day a week after.