Glaasje op... laat je rijden
Please explain it to me: I get that it means "Don't drink and drive.", but to me it looks like "A small glass on... lets you drive."
That's a tricky one.
"Iets op hebben" means to have consumed something.
- Ik heb twee glaasjes wijn op = I have had two glasses of wine.
- Ik heb mijn ontbijt nog niet op = I haven't finished my breakfast yet.
"Glaasje op?" is a shortened version of this phrase. It means "had a glass [of alcoholic beverage]"?
"Laat je rijden" is an imperative: "Let yourself be driven (by somebody sober)."
It's a kind of Dutch idiom, that's why you don't literary translate it into English.
In the 1960s, more attention was paid to alcohol in traffic. In 1965, the campaign "Glaasje op? Laat je rijden" started. This campaign would be a great success for many years.
Song on YouTube
"Glaasje" is used for jenever, which is served in a little glass. Jenever is a 32% vodka-like Dutch drink. The campaign Pentaan mentioned was very invasive: no way that you could not know the song, or even be able to get it our of your head.
My grandfather used to drink a "borreltje" (small glass of jenever) at noon. Every time I visited him, I'd get one too. I don't usually drink mid day, and I don't drink a lot of jenever, but those "borreltjes" still have a special place in my heart.