An issue has come up recently with our new son, in that he is at his most vocally unhappy when in the car.
It's not 100% of the time, but it happens daily. It's only rarely because of dirty diapers or being hungry, so we're having a hard time figuring out if there is a physical reason for his displeasure, or if it's simply emotional.
Regardless, he gets incredibly distressed during these times, which is highly unusual for him. We've tried everything we can to soothe him during this times, and any successes have yet to be repeatable. We've even tried adjusting the straps on the car seat itself to make him more comfortable, but it doesn't do much. He has no problem with the car seat when it's not in the car, even if the 5-point is fully tightened, anyway.
If it were a long road trip, we'd pull over and soothe him out of the car seat. But, this is occurring during the short trips in town (usually <15 minutes).
So instead, I ask what we can do for ourselves?
The primary issue I have while driving with him like that is that I end up distracted, no matter how much I try to focus on my driving. Since we're primarily driving in-town in areas with high pedestrian and biker traffic, I'm not keen on losing my focus.
We try playing the radio or music as counter-noise, but we've found that only seems to help the passenger, not the driver.
I am really asking for solutions for us parents when we're driving, rather than asking for ways to assess our baby. We've been trying everything we can think of, and will keep trying, but we've not got any ideas for ourselves. Half the time there's only one driver, so the other one of us can't distract/soothe him.
I think my wife fairs better than I, when it comes to being distracted. I personally have trouble trying to do anything but focusing on the road. Even adjusting the radio dials makes it very hard for me to focus.
We haven't ruled out a physical cause for his distress (motion sickness, ear pressure, reflux, strap soreness, gas, etc.), because they're very hard to test when it's only happening in the car. However, he's not crying as if he's in pain or ill, but only as if he's unhappy (it's the same cry as when he's set down when he wants to be held, but cranked up a notch). I have a feeling we'll see him outgrow this issue before we can solve this 100%. There are still going to be those times where he cries anyway, because of dirty diapers or hunger, where we need a solution for the driving parent.
Update: I've accepted the top-voted answer, but unfortunately nothing suggested has worked, neither has anything else we've tried. Since there are usually two adults in the car, we end up reaching over and physically distracting the little guy and talking clearly to him. It's an uncomfortable position, but it's the only thing that stops the crying when he gets like that. (That same type of crying has migrated to outside of the car, and the only thing that works is close-up play with one of us, until he gets tired out enough to eat and/or nap)