First of all, congrats on finishing drawabox! Only a handful of people ever make it to the end. (also note that this is my first lesson 7 critique so don't hesitate to ask questions if you're feeling confused about something.)

Starting with your form intersections, your work is pretty well done with a few minor issues. First this isn't really an issue but more of a suggestion, you should try to keep your forms the same size because that will help you see the intersection more clearly and will allow you more room to think in 3d space. I also noticed that some of your cones are stretched https://drawabox.com/lesson/2/8/stretched which should be avoided due to added complexity. Finally the cylinder in the middle should be converging instead of diverging.

Your cylinders in boxes is looking good, the only thing I would point out is that if you have the room to draw bigger you should absolutely go for it because it will allow you to think in 3d space better.

Continuing onto your vehicle form intersections ( which I'm going to assume are the less detail vehicles ) you've done a bit more than what was asked for. This exercise was just to remind you that the vehicles we are drawing are in the end just simple forms as a sort of warmup to the actual vehicles.

Moving onto your actual vehicle constructions, I'll start by addressing some of your notes. First of all there is no reason not to use a ruler and ellipse guide especially if you have used it previously. Doing these freehand takes away from the learning experience and instead forces us to focus on the accuracy of the line. On the point of using a ruler it can be used as sort of a guideline when setting up your initial bounding box so that you can see how the line converges with others. Also, if the initial bounding box is misaligned slightly you can account for that when you draw additional guidelines and go off of them instead of the misaligned line.

For your 2nd point it definitely is a pain in the ass to draw the vehicle inside of another box within the bounding box, but you shouldn't rely on guesswork because the whole reason we painstakingly plot every single line down is so that it trains our brain to use those invisible guidelines for the times when we actually use guesswork. Therefore the more precise we are during this lesson the better. I feel like you used a solid amount of precision, slightly more than the demos but I feel like you could have taken this a little further. For example on the garbage collection truck you could have maybe plotted where that middle indent was or maybe even the outline of the collection arm instead of relying on observation to do so. The reason we do the orthographic studies beforehand is so that we can fully focus on understanding how the vehicle sits in 3d space rather than deciding where to draw certain features while drawing it. By deciding where everything is going to go and how long and wide the vehicle is we can dedicate all of our attention to drawing the object.

Anyway, most of your constructions are very solid and it looks like you focused more on the end product by making it look good which certainly isn't a bad thing but I feel like with everything you've said so far I'm sort of torn on whether or not to assign a revision.

So here's the deal, I'll give you an optional challenge instead. If you choose to do this challenge I'd like you to choose a car or bus and subdivide it as much as you see fit. If you do this, make sure to include an orthographic view of the front and side which is subdivided as well. Also if possible I want you to avoid drawing on the reference and purely decide the proportions based on observation on the orthographic studies kind of like what you did on this except make each part clearly defined so that it's replicable on the bounding box like this. The point of this challenge is so that you can fully test yourself to be as precise as possible. Also don't add any detail to it after you're done just focus purely on the construction (but if you really want to just make sure to take a picture of it before you go in and add everything). Take as much time as you need and make sure to use a ruler and ellipse guide.

The reason I didn't make this a revision is because you clearly understand the lesson from what I see from the plane and the vehicles done with a ruler. So after deliberating for a couple hours I decided it would be best to make this optional. If you really want to test your patience you should go for it and reply to this critique if you do decide to do it. I've only done this once and it was during lesson 7 and it took me about 20 hours so I didn't want you to be held back by my distorted expectations.

Anyway, you've done really well and should be proud of what you've accomplished!

If you need further clarification on anything don't hesitate to ask! Good luck!