Some uses of "In" and "on"

In and on can be used in similar ways and sometimes overlap in meaning and usage. Bao asks some good questions about idiomatic use of in and on in the following sentences -- which word to use? Here are correct versions of each:

• There was a dog in the road so we stopped.
• The library is on River Road.
• It was a long street with all sorts of stores on it.
• I came across John in the street yesterday.

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Note that in British English in is sometimes used with street or road:

• We met at that pub in Fleet Street at ten o'clock.