青信号

青(あお) (ao, “blue”) + 信号(しんごう) (shingō, “signal”).

• (Tokyo) あおしんごー [àóshíꜜǹgòò] (Nakadaka – [3])
• IPA^(key): [a̠o̞ɕĩŋɡo̞ː]

青(あお)信(しん)号(ごう) • (aoshingō) 

1. a green traffic light, a green light (abbr. 青), green signal

This is literally blue signal which leads Japanese speakers of English to say "blue signal" when they mean green light more often than not.

• 赤(あか)信(しん)号(ごう) (akashingō, “red light”)
• 黄(き)信(しん)号(ごう) (kishingō, “yellow light”)

• 信(しん)号(ごう)機(き) (shingōki, “traffic light, the signalling device”)