pedestrian crossing and traffic lights - motion/na + Locative case?

Please, someone (preferably a native Polish speaker) explain the reasoning behind the two following sentances which I have been taught by a Polish teacher in class:

1) Trzeba pójść prosto na pasach, i potem trzeba skręcić w lewo... itd.
You will need to go straight ahead to the zebra crossing, and then you'll need to turn left... etc.

2) Pan musi iść na światłach, i potem skręcić w prawo... itd.
You have to go to the lights, and then turn right... etc.

I thought that na + Locative/miejscownik indicates position:

Jestem na rynku (I'm in the market square), jesteśmy na lotnisku (we are at the airport)
Aneta jest na poczcie (Aneta is in/at the post office),

and that na + Accusative/biernik indicates motion towards some fixed point:

Idę na rynek (I'm going to the market square), jedziemy na lotnisko (we are driving to the airport), Aneta idzie na pocztę (Aneta is going to the post office)

If:
pasy plpot.= zebra crossing
światło npot. = traffic light, and światła = traffic lights,

then I would have expected these sentences indicating motion,
'You will need to go straight ahead to the zebra crossing' to translate into Polish as:

'Trzeba pójść prosto na pasy' (na + Accusative/biernik) or, 'Trzeba pójść prosto do pasów '(do + Genitive/dopełniacz),

and 'You have to go to the lights' to translate into Polish as:

'Pan musi iść na światła' (na + Accusative/biernik) or, 'Pan musi iść do świateł' (do + Genitive/dopełniacz)

But, contrary to intuition, these two sentences of motion towards in Polish are:

Trzeba pójść na pasach (na + Locative/miejscownik)
Pan musi iść na światłach (na + Locative/miejscownik)

Maybe there is no logical explanation and that these are just set expressions and quirks of the Polish language... Please, all native Polish speakers, do not take these observations as criticisms. I'm just trying to understand the reasoning... Maybe I've completely missed the point, but it is just a little confusing!

Any ideas?

Thanks in advance
Pozdrawiam

Idź prosto aż do przejścia dla pieszych i potem skręć w lewo.


Idź aż do świateł i potem skręć w prawo.

One says often na światłach skręci pan w lewo/pójdzie pan prosto.

It should be translated as: at the traffic lights you should go to the left/ go straight.

Na pasach (though I don't use it) would mean at a crossing with zebras

So skręcić na pasach would be turn at the crossing (with zebra(s)).

these are colloquialisms (i guess something may be wrong with the second example you give)

Thanks for input... That is the problem... We are being taught that it is OK to say:

Idź prosto na pasach, i potem skręć w lewo... itd.

Idź prosto na światłach, i potem skręć w prawo... itd.

I guess then that 'Idź na pasach...' and 'Idź na światłach...' are only colloquial expressions without any logic to them?

Another related, but simpler question (if you would be so kind, please):

Would you say: Idę do Sądu Najwyższego... lub, Idę na Sąd Najwyższy... ? meaning

I am going to the Supreme Court, that is walking to the Supreme Court building.

Many thanks again.

iść na sąd (also iść pod sąd) never means 'go to the court' but 'go to trial/ (or in literary language - to go to jugdement (as with jugdement day)

iść do Sądu Najwyższego - is good enough for 'going to the Supreme Court (building)' though there is some slight ambiguity to it if left out of context because in Polish it also means to start a case before the court (or sue someone - if there is suitable context). (i guess it is simillar in English)

But if you just state 'Idę do Sądu Najwyższego' then most people will know you are heading for a building.

There is sometimes logic in cases where you go na instead of do.
some good examples are: lotnisko, boisko
in Polish you don't say jestem w lotnisku (i'm in the airfield/ airport) but na lotnisku 'cause it is perceived as a flat area/thing (like table) and things are thought to be on it). So if things are 'na lotnisku' and also 'jestem na lotnisku' - then 'idę na lotnisko' is a way to state it in Polish (things are on table/ na stole - you put them on the table/ na stół).

the same goes with 'boisko' (playground - flat piece of land), 'łąka' (meadow) and many others (however 'pole' (field) can be either w polu or na polu (in the field) but 'do pola' is rather regional and standard Polish is 'na pole'.

Logic like that is not that obvious (well, to me it still is) in case of stacja (na stacji, na stację) - one can think originally stations where thought of as pieces of land containing platforms.

maybe more some other time
little nephew IS APPROACHING :)

Idź prosto na pasach is incorrect and sounds strange even if colloquial expression and I think it is made by your teacher ;)

In case you have any doubts put sentence in Google "this exact wording or phrase" blank and check results counter.

There is a clear difference here. 'W polu' has more general meaning and 'na polu' is more specific. It can be explained better with an example:

Rolnik pracuje w polu (no matter what 'pole' that is)
Rolnik jest na polu (on some specific 'pole')

But in other contexts it may be different e.g.:
w polu elektrycznym = in electric field
w polu karnym = in penalty area (in soccer)
w polu widzenia = in field of vision

but:

na polu walki = in battlefield
na polu minowym = in minefiled

Cinek