How can you tell when you can summon your vehicle?

[iBe ImmorTaLiiTy]

So, are there any icons or telltell signs that notify you that you can (or can't) use a vehicle? Or do you need to just try and summon your vehicle to find out (surely there is a better way) ?

[DakotaThrice]

Pull out your Ghost and in the bottom left of your screen where the prompt for "Open Director" is there will also be a "Summon Vehicle" prompt if your vehicle is available or an "Unable to summon" message if it isn't. If vehicles are globally disabled in a mode such as most of Crucible or Gambit then hat message just won't appear at all.