I agree with many others here, I believe these parents set off high and died together of an accidental overdose.They pulled over because they weren't feeling well, passed out and died either of exposure or an overdose. People drive high all the time; if you are an addict you LITERALLY drive high all the time.
Couples accidentally overdosing together happens way more often than you'd think, many with children in their home or in tow. Only a few days ago a couple died of a drug overdose, and their infant daughter died of starvation before they were found.
Sometimes something different or extra is added to their drugs that causes death, maybe it's stronger than they are used to, or sometimes they inject too much.
This is just in the past few months:
https://www.washingtonpost.com/news...starvation-days-later/?utm_term=.61bc57ec90f6
http://www.nydailynews.com/news/cri...oses-daughter-alerts-school-article-1.2817758
http://www.nydailynews.com/new-york/queens/young-couple-dies-drug-overdose-queens-article-1.28429457
Last year this couple overdosed in their 7-month-old baby's Children's
Hospital room! Mother died, father had to be revived. If he wasn't in a hospital no doubt he would have died as well.
http://whnt.com/2016/01/07/parents-...on-heroin-in-7-month-old-babys-hospital-room/