Thanks everyone! Loved the detailed description too. I learned Chinese before learning Japanese so I get so confused with the kanji and their meaning a times. I didn't realise 気をつける meant "to be careful/ to pay attention". Because in Chinese "to pay attention" would be 注意 and I see this on Japan subway doors all the time, so I assumed it meant the same in Japanese. ("> < )

Let's watch out for cars when we cross the street(road). 道を渡るとき(michi wo wataru toki) = when we cross the street. The usage of this "toki" usually suggest that is being used as a connector between what is before and after of it. The typical translation is "when". But there are more usages for toki, so dont think it's always translated as "when". More examples, 彼は若い時に欧米を漫遊した (kare wa wakai TOKI ni oubei wo manyuu shita) He visited Europe and America WHEN he was young. 初めて彼に逢った時は変な男だと思った (Hajimete kare ni atta TOKI wa hen na otoko da to omotta) The first time (WHEN) I met him , I thought him a strange man. ------------------------------------------------------------------------------------------------------- 車に気をつけましょう (kuruma ni ki wo tsukemashou) = let's watch out for (be careful about) cars 気をつける (ki wo tsukeru) means: to be careful, to pay attention, to take care about someone or something. If you see "mashou" instead of "tsukeru" or "tsukemasu" it's just a volitional meaning in the verb. Tsuzukemashou = let's continue. Hanashimashou = let's talk, Ganbarimashou = let's do our best try. and so on. The NI particule just implies that the think you need to be careful about is "kuruma". That's because NI sometimes indicates to whom the action of the verb is leading to. Hopes this help.

It's a phrase essentially stating that you should be mindful of cars when crossing the road. Here's my attempt at a more literal translation: 道(road)を渡る(crossing)とき(time)、 車(car) に気をつけましょう。(let's be careful of) I hope I was able to help

I think it suggests you should be careful to watch out for cars when you cross the street. Hope this helps!