Can you take Diazepam and Travel tablets together?

I have diazepam tablets which work very well for my anxiety, i started off on them for 2 weeks every day, but now just take one (or even half one) only if i have a panic attack or have to go somewhere i would otherwise find really really hard. Anyway, i am going to pick up a new puppy with my family next week (yay!) but the journey is 1 and a half hours there, then almost imediatley another 1 and a half back. I am very bad at travelling so usually take a travel tablet, and also if we get stuck in heavy traffic i sometimes need half a diazepam to prevent a bad panic attack. Are these both okay to take together if it comes to it? i wasn't sure because they are both "drowsy" tablets so.... Just wondering if they are safe to take together or not really?