Why did the 黄色い線 become the 黄色いブロック?

Question

Until a few months ago, I am absolutely sure in every single train station I had ever been the announcement was something along the lines of "黄色い線の内側でお待ちください".

Then, out of the blue, one day the word 線 became ブロック. If I'm not wrong, I would say that I noticed this mostly at Tokyo Metro stations, while JR seems (thank god) to still be using 線. This is just based on personal experience and I might be wrong.

My question is, why this sudden change? When exactly did it happen? Is there a particular reason why what has always been a "line" needs to become a "block"? More generally, is the choice of a loan word a coincidence? A very wild guess could be that with the approach of Tokyo Olympics loanwords will increase even more and hence that choice.

Anyway, this has been bugging me for a while and I'm just curious to know if there is any specific reason for this change.

PS. My experience so far is only in Tokyo.

Answer 1

I doubt it's related to Olympics or internationalization; changing one word to an (English-origin) loanword will not help foreign tourists at all. Some native speakers seem to have noticed the same trend, but I could not find the authoritative reason.

One reason I can think of is that this yellow paving is currently becoming wider to the point where it's hardly called a "line". Until recently, this yellow 点字ブロック was made only of dotted blocks. But a recent government guideline says the dots should be accompanied by "bars" to indicate which side of the paving is safer to visually impaired people.

(image from 京阪電気鉄道's press release)

Now this looks almost like a yellow area rather than a yellow line. These bars are called 点字ブロック内方線, and an increasing number of stations are installing new 内方線. So this may be why they started to call them simply as ブロック instead of 線. (Still, this is my guess.) Tactile paving has been called (点字)ブロック ever since it was introduced, so I don't think it has something to do with "recent overuse of loanwords".

EDIT: This chiebukuro question shows another reason why ブロック is better. 黄色い線 is confusing to visually impaired people because a 線 can possibly refer to something they cannot perceive. By clearly saying 黄色いブロック, they can be sure that it refers to the thing they are absolutely familiar with.