Isn't a yellow light supposed to mean proceed with caution?
Beyond their use in driving vehicles, traffic signals are used as various metaphors in daily life and business. For example, a green light is used as a metaphor for states such as "proceed" or "going well," a yellow light for "caution" or "warning," and a red light for "stop" or "out." Because the everyday image of a yellow light suggests "caution," it is sometimes interpreted in the context of driving as "caution" or "proceed with caution," and there are even books that state it this way.
What is the meaning of a yellow light under the Road Traffic Act?
However, the meaning of a yellow light as defined by law is actually different. The Road Traffic Act defines a yellow light (yellow illumination) as follows.
1. Pedestrians must not start crossing the road, and pedestrians already crossing the road must promptly finish crossing or stop crossing and return. 2. Vehicles and streetcars (hereinafter referred to as "vehicles, etc." in this table)
must not proceed past the stop line. However, this does not apply if the vehicle is so close to the stop line when the yellow light is displayed that it cannot stop safely.
In other words, the basic rule is that when the light turns yellow, if you have not yet entered the intersection, you "must not proceed," and the only exception is when stopping would pose a safety issue.
What is the meaning of a flashing yellow light?
There are several other types of yellow lights. In the case of a flashing yellow light (flashing yellow illumination), the Road Traffic Act stipulates the following.
Pedestrians and vehicles, etc., may proceed while paying attention to other traffic.
At intersections and crosswalks, there are single-light or three-light signals where the yellow portion is flashing, and vehicles may proceed while paying attention to other vehicles and pedestrians.
In places where intersection signals are difficult to see, such as on curves or hills, there may be a signal labeled "advance warning signal" that flashes yellow. The meaning of this is basically the same: it means there is an intersection with a traffic signal ahead, so proceed with caution. There are various types, including single-light, two-light, and three-light versions.
What is the meaning of a yellow arrow signal?
There is also the case of a yellow arrow signal (yellow illumination arrow). The Road Traffic Act stipulates the following.
Streetcars may proceed in the direction of the arrow regardless of whether the signal is a yellow light or a red light.
In other words, this is a signal for streetcars and does not apply to regular vehicles or pedestrians. Occasionally, a single signal unit may contain lights for both streetcars and regular vehicles, so caution is required.

At this intersection, a streetcar runs parallel to the direction of travel, and the yellow arrow on the far left of the lower 3+1 light unit is a signal for the streetcar.
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