I doubt you'll kill the Ajuga but you will squash the stems which won’t be very aesthetically pleasing.

Without a photo it is hard to judge, but typically pea gravel is a terrible choice for gardens, patios patios, and pathways. It gets stuck in shoe treads, migrates into the nearby lawn or planting beds (even with edging), shifts underfoot, collects weed seeds. It looks gorgeous in pintrest photos and other garden imagery, but IRL but unless you have a gardener, I wouldn’t ever suggest using pea gravel on any part of a path.

Oh, @NHBabs z4b-5a NH, all of that has been my worry with pea gravel! What to do, what to do?!!? My next door neighbors have a pea gravel/ stepping stone path and it looks nice, but they do have gardeners that are over there tidying everything ALL THE TIME. (I can't imagine the cost!). Anyway, thank you. Do you think ajuga might work, or would you be concerned about crushing the stems on garbage day and making them unsightly? Any other ideas? Otherwise, perhaps I am back to the drawing board . . . . Thank you!

I only wish you could kill ajuga.Unfortunately someone planted some in my yard long ago and it spreads everywhere if I don't kill it. I do agree with @floral_uk z.8/9 SW UK that the squashed stems will not look good. Something like dwarf mondo grass might be nice and it stands up to traffic as you describe although it may be too clumping for your application. It's supposed to grow in Zone 6.

Thank you, @gardengal48 (PNW Z8/9), I was interested in ajuga because I read it is evergreen, but maybe that is not the most important characteristic. I will look into the options you suggested!

Pretty sure ajuga will survive...i used it in Aspen ,Co. successfully...spreading growth depends a lot on soil quality..mosses work really well...and if you like pea gravel you can lay weed cloth.....beneath it...over time ....walking thru with a squirt bottle of weed killer will curb growth...it all depends on your philosophy about keeping your garden organic...on which case a squirt of water with salt and vinegar works safely....personally i love the pea gravel look as it can be so free form and graceful...but you will always need to maintain it...for me I find it sort of a zen experience that i enjoy

All of the GC's I suggested are evergreen. I don't see any point in a groundcover that is not :-) In a particularly cold winter the blue star creeper may be only semi evergreen.

Awesome, thanks @gardengal48 (PNW Z8/9)!!