From Richard Russell, who says he "worked on Google Maps Data partnerships"
Like in similar products, Google maps ETAs are based on a variety of things, depending on the data available in a particular area. These things range from official speed limits and recommended speeds, likely speeds derived from road types, historical average speed data ...
Yes on bing maps you can add shapes like polygons to the map. It also seems you have been looking at the wrong Bing page.
This link tells you how to add polygons. On Bing the only way to do it is to edit some code but that page fully explains it!!!
[in XAML] use this to make a triangle.
I also have English OS, Firefox using English locale, and I am in the US.
So to force me to use Japanese map service, I went to www.bing.co.jp (same as I do for Google when I explicitly want Japanese results), the select Maps from the top menu. Since you are in Japan, Bing might be sending you there by default.
Then I entered "10 Downing Street, London" as ...