I want to thank you for asking a great question!
My main hesitation in answering the question is how we each understand the words ‘sin’ and ‘mistake.’ I think there are some ways to define a mistake that overlaps with our definition of sin.
For instance, in your example, perhaps it was a mistake to forget to use your blinker, but a sin to be distracted by texting on your iPhone. Or it was a sin to be out driving after not sleeping for two nights and risk driving in a state of extreme fatigue. And so on and so forth - I don’t at all mean to be blaming you and I’m very glad you’re both okay.
To speak more broadly, I have a hard time constructing the scenario where a driver is:
1 - Intentionally doing everything for the good of their neighbor (especially other drivers) and
2 - Not allowing himself to be distracted from what it means to love other drivers in any way, and yet
3 - Forgetting to put on the blinker and/or pulling out in front of someone.
Actively loving others would mean that any driver is putting their interests above their own, fully alert, the car was well maintained, etc. Not being distracted from this task would mean the driver’s phone is turned off, the music is calm, he doesn’t start daydreaming about a challenge at work, etc.
What I can imagine, since I do it myself, is to be driving in a generally responsible way, but not in a morally perfect way, and because I am overall a reliable driver, not fretting too much if I sometimes don’t turn on my blinker. I haven’t been in an accident since… high school? I pay attention to speed limit signs, traffic conditions, etc. The occasional small mistake, given my generally responsible driving patterns, is truly harmless.
At the same time, I think we do need to acknowledge that Jesus was fully human and had human limitations. As I browsed some different takes on this question, I found some suggestions by Conrad Gempf, New Testament lecturer at the London School of Theology, to be interesting:
"But while we do learn from making mistakes, I’m not sure that’s the only way to learn. We don’t have any record of Jesus making a mistake that we can be clear definitely is one, even though the Gospels are willing to say the things that he didn’t know.
“If a learner says with confidence: ‘I know how to spell that word; it is spelled skool,’ that’s a mistake. If the learner says: ‘I don’t know how it’s spelled, but it sounds like it might be skool,’ that’s not a mistake; that’s an experiment or a guess. I think Jesus might have guessed and experimented, but I don’t think that he will have been convinced of the truth of something that was not true.”
I think the starting point of exploring this question, for me, is to attempt to imagine what kind of mindset and approach I would have to literally every decision if I was morally perfect. Given moral perfection, what kind of student would I be? It seems that the complete absence of sin would change so many of my starting points that the room left for what we call ordinary human mistakes would become quite small. And that those mistakes might (might) be better identified as experiments or attempts.
What do you think?