Christian:

I tried looking at the signboards of businesses along the side of the road, looking for the point where the address would change from Fujairah to Sharjah, but couldn't detect any change upto the Madha road junction.

IMH,

Did you try to look for the emirate's flags? Perhaps not easy at this specific border (because Fujeirah only uses the union flag since 1975), but perhaps a good sign at other borders?

Or perhaps the emirate's flags are not widely flown?

Not a very good idea at Dubai/Ajman border or Sharjah/RaK border either since they uses the same flags.

_______________

Christian Berghänel

Sweden