So still the same coworker as my last threads

yes i am going slowly.
We drive alot together at work. I dont even have a licence so she does the driving. Not a problem for me even tho some might see that as a lower value. It's not a problem for her either (well, at least she looks through the fingers on it, or she might even like it. idk, but who cares right? it might even give me a slight advantage, seeing my hands are free to do stuff and i dont have to concentrate on the road and driving or something.)
Problem is nothing really happens in the car (except mundane conversation, some teasing, verbal flirting, work talk etc.) until we get out of it. We stop here and there just to get out of the situation where nothing seems to be able to happen.
we even have a pretty long journey in a while (work related ofc, with a stop in another city). like a one hour drive, each way. that means two hours of what i mentioned above, and akward silences WILL be a fact if i dont step up, or stop the car every 10 minutes lol.
1. How do i step up on the short drives
2. How should i handle the long 2 hour journey.
Other tips/questions?