Driving in Japan: Why Do Japanese Highway Buses Have Blue Flashing Emergency Lights at the Back?

Self-driving road trips across Japan have become an increasingly popular travel style for international visitors. For those who have rented cars in Japan, have you ever wondered why certain intercity highway coaches and public buses feature an additional pair of blue lights installed above their turn indicators?

Chances are, you may have never seen these blue lamps illuminate, leaving their intended function a complete mystery.

In truth, these blue rear lamps remain dark under ordinary driving conditions. Their core objective is to signal following motorists and law enforcement officers that the vehicle has encountered an active “abnormal emergency situation.”

Scenarios that trigger these emergency lights include severe mechanical breakdowns (such as brake system failure), an onboard medical crisis, or even hostile criminal emergencies like armed hijackings.

Furthermore, when these blue emergency lights begin flashing, the exterior digital LED destination display may also alternate with warning text reading “Abnormal Situation / Emergency (異常事態発生).”

Consequently, if you are driving on Japanese roads or expressways and spot the blue lights on a preceding bus actively flashing, immediately maintain a substantial following distance and steer clear to prevent being caught in a hazardous roadside incident.

Because these lights are an optional safety accessory rather than mandatory national equipment, they are primarily installed on long-distance expressway coaches, while remaining relatively rare on ordinary municipal city buses.

Recommended Car Rental Portals for Japan: Rental Cars, Tabirai Japan Car.