Pretty much every Halo fanboy has already seen the real life (and fully operable) of Master Chief's preferred method of transport that WETA produced a number of years ago. Back when they were still involved in the Halo big screen adaptation.
But that was then, and this is now; Halo 4 introduced a slightly different Warthog, and 343 Industries, the new stewards of the Halo franchise, figured that a brand new version of the real-life Warthog was in order.
So they called up the Aria Group, which specializes in replica vehicles for Hollywood movies. According to the LA Times, it's almost eight feet tall, more than eight feet wide, and more than seventeen feet long.
Though despite such impressive numbers, it's actually twelve percent smaller than its in-game equivalent, so it's not true 1:1 scale I'm afraid. This was necessary so it can fit in a trailer that can navigate public roads.
The new Warthog was built upon the chassis of a Hummer H1, has 49-inch tires, and cost "hundreds of thousands of dollars" to make. Which is essentially chump change for MS, given how well Halo 4 did over the holidays.
Though there's a real reason why money was spent on the vehicle, which will be used primarily at trade shows, and isn't for the amusement of 343 Industries employees during lunch breaks. According to Frank O'Connor, Halo franchise director;
"The first time people set eyes on it in real life, that's when you see where the value is… When somebody is standing next to the tire, and it's coming up to their shoulders, they're getting a sense for this thing they've grown up with."