The CDC say that, from 1999-2012:
Total drug-poisoning deaths rose from 16849 to 41502 (246%)
Opioid analgesic deaths rose from 4030 to 16007 (397%)
Heroin deaths rose from 1960 to 5925 (302%)
and that there were 36415 motor vehicle accident fatalities in 2012.
That would suggest that prescription drug overdose is rather more of a problem than heroin overdose, both in numbers and in rate of increase.
