A slight issue, I'm fairly certain that I'm correct in my interpretation but it still ends up being a bit of an annoying problem determining the intent of the rules. The issue is that in most cases when I see the published adventures listing vehicle units I assume they mean the Leman Russ, and I can see that one easy. The area where it gets trickier for me is something like the scout units from HotE or the mechanized infantry is the question about if those would be considered vehicle units.

On the one hand, the vehicles give a pretty strong edge, the Chimera having some good weapons and armor to protect those within as well as possibly just serving as a rolling protective wall. Not to mention that it can have firing slits in it, overall pretty helpful (especially when your team carries hotshot las guns)

On the other hand, looking at most of the vehicle oriented challenges for the listed adventures would probably carve up a Chimera or chicken walker. Not to mention that in almost every case that I've seen so far you can basically find a chimera sitting around for you to pick up either as part of standard gear or something that you can find.

I lean towards saying that mechanized infantry is still infantry, but there is still a bit of a nagging question. Not to mention that part of my problem is bluntly that I wish that the vehicle squads were more clearly defined. Any thoughts from others might help.

Not much help from me, sorry.

I've encountered exactly the same problem and am likewise rather certain that the authors are only worried about russes.

Chimeras seem not to get a second thought, which is sad since mech inf is such a nice regimental type.

i usually add a few enemies with AT weapons, krak missiles or grenades, Dark Eldar Lances to offset the chimera/sentinel

makes the players think more tactical too from my experience

I am not sure what your question is? I'd agree that standard adventures don't cater well to vehicle units and that it takes a bit of GM-ing to rewrite it to suit them. The way I'd handle vehicle based adventures is to make sure there are plenty of challenges for vehicles....and to make combat cartoony yet logical. With that I mean, when fighting against most infantry, the vehicle should make it much easier as it provides both cover and additional (heavy) weapons. Historically, infantry vs. mechanized infantry doesn't go well for the footsloggers unless they bring arty to the fight....At the same time, vehicles against heavier vehicles also doesn't go well for the lighter vehicles.

Typically, I'd let the players roll over most enemy infantry but the enemy commander would then dispatch his reserves (similar or heavier vehicles or perhaps even air assets) to hunt down the players' vehicle(s). And god help them if they run into a pak front (which would have been made clear by numerous burnt out hulls as a warning...). And encourage them to dismount when required during the adventure.

At the same time, I wouldn't let an infantry team (just) get their hands on a vehicle. Vehicles are assigned to units and are not just given out to anyone who doesn't feel like walking. Sure, you can 'liberate' a vehicle but that means risking the wrath of the owners/military police/every check point you pass without papers/ID etc.

War movies (Dirty dozen, Kelly's heroes) and books such as W.E.B. Griffin's show how you both can 'game the army system' but that the system is not that easily gamed and that it takes both flair and ability to work your way around regulations....

Ranonclese, the point of the question is that when they say 'vehicle unit' for certain adventure upguns they don't clarify very well what that is supposed to mean. Basic point, mechanized infantry could be called a vehicle unit, but given what the vehicle unit additions are that would seem a tad...excessive. Not to mention the fact that all the published adventures I have found thus far seem to hand the players a chimera for the missions or at least make it very easy to get so it would seem that chimeras are in fact assumed for most groups. THIS is the problem that I encounter hence why I was wondering if anyone had a clearer idea for what would constitute a vehicle unit. I mean the chicken walker things could be called that too but I'd still hesitate to list them in that category, frankly I'd say the most accurate one would probably be a leman russ unit.

You might have a Tauros; you might have a Chimera; you might have a Sentinel. WE assume you always bring a Russ. Dudes buried in cover-bunkers (cover vs battle cannon anti-infantry shots, assume it has armor like a Russ, AND health like a Rhino, so a few lascannon shots WILL be necessary to break it), sporting krak missiles and multi-meltas, make short work of anything that isn't a LR.

With these, I presume that they say "there are so many vehicle options, each with radically different armor/gun options..." and hope you'll say "well, if this is what they suggest for a Russ, than a Chimera can take this, minus the..." In a big, pitched battle, just because YOU don't have a Russ doesn't mean your allies around you don't, so it might still be good for them to word it as is. I like to look at engagements from the squad level, but this is the game where you can say "we have an army", and the other guy can't always throw in his Hulk. There should be numerous opportunities for full-scale army battling to be going on around your squad, and they might have some different toys than you.