Nominally, 1/48 scale is commonly associated with 36mm figures, whereas for 32 (or large 28s) the most popular scale these days seems to be 1/56 to 1/50. By that logic, 1/43 might be a bit on the large size - they definitely are a bit too big for 28mm figures IMHO, but it can be disguised somewhat.
That said, if you want to use them for terrain or cover, it might work, especially if the actual figures are not based on flat washers. Also, it is very difficult to find proper cars in the smaller scales, so if you can get some for a reasonable price, the slightly larger size might be an acceptable tradeoff.
And finally, the Fallout aesthetic (even described so in one of the artbooks, if I am not mistaken), in line with the 1950s retrofuture look, pretty much aimed for "either huge or tiny cars - nothing in between", so you'd get that "land yacht" (in German, "Strassenkreuzer", i.e. "road cruiser") feeling sorted out.