Despite the Audi having the right of way, had it not been speeding, the Hummer might have had time to clear the intersection.
That's not to say that whoever was behind the wheel of that old A8 was more to blame than the limo driver. The latter should have paid more attention, without assuming that any incoming traffic would stick to the speed limit.
However, it almost seems as though the driver of the Audi didn't brake as hard as they could/should have once they noticed the Hummer poking its nose where it didn't belong.
This crash is a perfect example of why people should slow down at intersections, even if they have the right of way, have a green light and even if they're not speeding. You never know who's out there not paying attention.
As for the impact itself, we could call it moderate. Let's hope the person driving the Audi was wearing a seat belt.