Hi,
I need your consultation about Nepal-China border, and about road from Lhasa in China. I listened, that foreigns need special permission to visit TIBET, and this permission costs 100$.

1) if traveller needs only transit via Tibet, is permission necessary?

2) if necessary, does _transit_ permission exist? how many does it cost for your citizenship?

3) is there international gate (not only for citizens of China and India)?

4) what are another problems and solutions on this road? what are additional, unpredictable possibilities on this road?