Quiet Cabin Etiquette (車内での静粛 - Shizuka)
The courtesy of keeping conversations at a moderate, quiet volume and avoiding making voice calls on mobile phones inside a taxi cabin, ensuring the driver can focus entirely on safe navigation.
Rooted in the fundamental Japanese societal norm of avoiding 'Meiwaku' (nuisance/annoyance) to others in shared spaces. Although a taxi is a private ride, it remains a shared enclosed cabin with the driver.
If you receive a phone call, answer briefly and say 'I'm in a taxi now, so I will call you back later.' Friendly small talk with the driver is perfectly fine, but shouting or playing audio out loud without headphones is a major faux pas.
What is the correct quiet-cabin etiquette inside a Japanese taxi?