It is now 1 p.m and I've been travelling for 4 hours and have just arrived. The journey was quite exhausting so I say: "I'm tired because I've just been travelling for 4 hours.
At 4 p.m I'm still tired of the journey, but a couple of hours have passed. Can I still say: " I'm tired because I've been travelling for 4 hours, or would it be better to use present perfect simple: "I'm tired because I have travelled for 4 hours ( today).