Bullbars and "raised" wheels

I need help in rigging trucks for MMD, because I just realized this: this is how the bumper is attached to the truck when the hood/cab opens up. But with a bull bar bumper like this: , how will you be able to open the hood/cab if this bull bar is permanently welded to the bumper????? Like, if you're ever going to get access to the truck's engine to cool it if overheated or check the oil level, then there's no way to remove the bull bar bumper's bolts as you don't have the necessary tools used from a truck service garage. Even if you do manage to pull it off without having it squash you, it's going to be tough lifting it back into place without a crane as bullbars are made of solid steel.

Next, why do certain trucks have... One, two, or more pairs of wheels "raised off the ground"? I know it sounds strange, but......... Instead of being strapped to the back like a jeep or a hummer, these wheels are strapped to the sides of the truck, just behind the cab, and they look like they're just hanging a few centimeters off the ground. They don't look like they're spare tires, because the tires seem to look a bit too small to fit any of the wheels on the most part of the truck.

Bull bars are made of aluminium and are not to bad to lift. The bolts are eye bolts and can be tightened and loosened with a jack handle which every truck should have in its kit.

The bullbar is hinged and held in place by the two eyebolts.

The "raised off the ground" wheels are what we call a lifting tag axle, or the Americans a "pusher" axle. It is able to raise and lower, usually with airbags but sometimes hydraulic, and is lowered to spread out the weight of a loaded truck (more axles on the ground means less weight per axle, which is important). They raise to increase maneuverability, to decrease tyre wear when empty running, or both.

Undoing eye bolts and lifting a heavy bar can be a disincentive for some drivers to do morning engine checks.

These blokes have come up with a spring assisted bar and air operated fastening system.

I see, because Mixmaster from Revenge of The Fallen has both the bullbar I mentioned and that pusher wheel on his undercarriage. And he's the only Mack cement truck that I know of that has both those accessories.