Could it possibly be that 信号 （しんごう） is used because it sounds a bit like “signal” as in traffic signal in English?
I don’t think so… 信号 makes sense to me, at least for traffic light. The lights are like a number series and you need to trust it to keep safe and keep the traffic moving.
Huh, I never really thought about traffic lights in terms of number sequences.
I think numbers also have an association with orderliness? Which might explain 交番 a bit as well?
号 does not only mean number, it also means to give instructions (call out) or signal something. It makes sense as a compound. Plus, it seems to be the same in Chinese.
Still, I wouldn’t rule out that it is related, wiktionary even gives samjna for Telegu (whatever that language is), so maybe the concept was exported long ago.
I’ve always been amused at how much 立派 and 突破 sound exactly like Australian slang terms with the same meaning.
As for 交番, it’s supposedly a contraction of 交替 (shift rotation) + 立番 (standing watch).
Occasionally I see beginners ask if things like 名前 are from English… Most cases of this are coincidental.