I have included a little mechanism on the bottom corner of the sheet that needs to be folded into an 'M' shape & then stuck inside the base of the card, to prevent the finished card from 'splaying'.
Sorry, don't know how I forgot but I haven't marked the central fold line, but it is actually obvious as you just need to fold the main body of the card in half.
I was aiming for a London 'black cab' shape & I don't think it turned out too badly! I have even given you the extras such as headlights & windscreen etc. & marked the place where they go on the main template.