In Japan, road signs are standardized by the "Order on Road Sign, Road Line, and Road Surface Marking" established in 1968 with origins from the Tokyo Metropolitan Police Department's "Order on Standardization of Road Sign" of 1934 and the Home Ministry of Japan's "Order on Road Signs" of 1942. The previous designs have been used since 1986 after several amendments of order. They are divided into "Principal Sign" and "Supplemental Sign".
Principal signs
Principal Signs are categorized into 4 types; guide, warning, regulatory and instruction signs.
Guide signs indicates directions or distances of the road. Guide signs have dark green backgrounds and white text for expressways. In urban areas and on national highways, direction signs have dark blue backgrounds. The signs are normally written in Japanese and English. Since 2014 Vialog is used as the typeface for English words and Place name Transcriptions.
Warning signs
Warning signs warn drivers of dangers or situations that they must pay attention to. Their design, black pattern and border on yellow diamond, is based on the U.S. MUTCD.
Regulatory signs
Regulatory signs show the regulations of each roads in order to keep road condition and prevent dangers of traffic. The stop sign is a red, downward-pointing triangle, with the text & "stop" in white. Prohibition signs are round with white backgrounds, red borders, and blue pictograms. Mandatory instruction signs are round with blue backgrounds and white pictograms.
Instruction Signs
Instruction signs show points and devices on the road that drivers should pay attention.
Supplemental signs
Supplemental signs are usually put just below the principal signs, and shows their valid range like time, day and category of vehicle. They are equivalent to the "plaque" of the American MUTCD. The width of the plates is usually 60 cm, and the sentences should be less than 7 characters per a line or 3 lines. When the sentences can not be shortened less than the limitation, they should apply changeable signs.
Other signs
"Stop" sign changes
In 2016, it was announced that the Japanese National Police Agency was considering changing the design of the "Stop" sign used on Japanese roads since 1963 from the inverted red triangle sign to an octagonal design more closely conforming to the recommendations of the 1968 Vienna Convention on Road Signs and Signals. The inverted red triangle sign was introduced in 1963 ahead of the 1964 Tokyo Olympic Games, and replaced the earlier red octagonal sign used from 1960, which in turn had replaced the yellow octagonal sign used from 1950. It was later decided to make the stop sign bilingual in both Japanese and English, but to maintain the inverted triangular shape.
