The Diet passed into law Tuesday a bill allowing drivers to use their smartphones while their cars are traveling autonomously under certain circumstances and if they are able to shift to manual driving immediately during an emergency.

The bill to amend the road traffic law, which includes rules on so-called Level 3 self-driving of vehicles under certain circumstances, passed the House of Representatives. The amended law will come into effect by May next year.

In Level 3 situations, automated driving is permitted under conditions that have to do with the type of road, the vehicle speed and other factors. A Level 3 situation includes a traffic jam on an expressway. Drivers will need to switch to manual driving if the conditions are not met.

Under the current road traffic law, people are banned from talking on their mobile phones and looking for long periods of time at navigation systems, televisions or other devices.

The amended law will allow such actions if drivers are able to change over from automated to manual driving immediately.

While the revised law will allow reading and eating, it will prohibit people from drinking alcohol, as there is a possibility that they will have to drive their vehicles manually.

The amended law will also require people to equip their vehicles with a device that will record the operating situation of cars and save the data, in order to detect a system malfunction at an early stage and identify the cause of any accidents.

Police will be able to ask drivers to disclose such information if their car is found to have a defect.