particles - この道をまっすぐ行ってください。 Why を and not で?

In a quiz, I got a question where one had to complete with に、を、で or が the following sentence:

この道（？）まっすぐ行ってください。

The correct answer being:

この道をまっすぐ行ってください。

It always seems more natural to me to put で here instead of を as 道 describes where the action will take place.

Could anyone please give me the reason behind this choice in Japanese?

Answer

There are basically four choices with motion verbs in Japanese. Each has a slightly different implication.

• に - "to" indicates the final goal of the travel. If chosen in your sentence it would be slightly nonsensical due to the この "Go directly to the street right here"


• で - "in or around" tends to indicate meandering inside of the boundaries of a location. In other words, で treats the street not as a path to travel along, but as a place to move around inside of. This might be appropriate if you were at a street-fair or similar event (although this would probably be better with a verb other than 行く). In this case, however, the まっすぐ contradicts the implication of で, so it's not appropriate here. (EDIT: As several commentators have pointed out, で is a reasonable choice if there is a discussion of which way to travel. But this requires a context in which the conversants are discussing different options: "this road", "that sidewalk", "hang-gliding")


• を - "across/along" indicates traveling the length (or a significant portion thereof) of the road/mountain/sky/(distance). More details are at this question


• へ - "to" - very similar to に, and へ can be replaced with に in pretty much all situations involving movement verbs. There is a slight emphasis on the "direction" with へ, such that へ is often called the "direction particle", as opposed to the "destination particle" に.

There are, of course, other possible particles for marking destinations, such as まで, までで, までに, the catch-all topic marker は, and even simple omission.