Are there any recommendations for pair-driving long distances? [closed]

After chatting with some sailors about their watch schedule (the group happened to do 4 hours on, 12 hours off), it got me to wondering if there is an optimal way to split up driving long distances between two or more people.

For example, if my wife and I had ten hours of driving in front of us, is there a way to split the driving that is the safest and least fatigue-inducing? Perhaps we each take 2.5-hour shifts. Or we could each drive five hours straight.

Since this is kind of a vague question, I'm looking for answers supported by recommendations from groups (maybe a long-haul tandem truck driving group?) or scientific research that would be a general answer for a group wanting to split driving responsibilities.