Can be Trap Bar DL (low handles and heels elevated, in order to maximise knee flextion over hip extension) a decent substitute to Back Squats?
I train alone, in a home gym with no safety arms (just squat stands) and no spotter.
Just for safety purposes
Tip: A New, Old Way to Build Massive Quads | T Nation (t-nation.com)
It cannot. But you can get big and strong using it.
I’ve trained alone in a home gym with no safety arms and no spotter and still squatted. It’s very possible.
Isn’t it quite the same motion as long as knee flexion is involved?
Not trying to be defiant but genuinely curious on why it would be that different as far as quad developement is concerned
Your question wasn’t about quad development though: it was about as a replacement. Is your question now specifically about quad development?
It is replacement.
What I mistakenly omitted is that i have bodybuilding purposes, not general strenght nor powerlifting. Thus squats are intended as a mean to develop (mainly) quads and glutes
Just getting big and jacked.
It cannot be a replacement because the trap bar does not load the spine in the same manner a squat does.
Perhaps better phrasing would have been ‘Can trap-bar DLs be performed in a way that stimulates quad development?’ Yes they can.
A question you didn’t ask, but might be worth considering: Are quad-emphasizing trap DLs safer than squatting without safety arms? I’d have to ponder on that one. 
OP, @T3hPwnisher has this annoying habit of answering the question one asks, rather than the question one wants answered. 
I’ll rephase: i mistakenly omitted that I was talking about my bodybyiding goals, that is to say Quads and Glutes developement.
Thus since I find it safer to perform trap bar DLs that way, can it be considered a decent subsitute for quads and glutes Hypertophy?
Anyway got it. thank you
Yes it is a good replacement for bodybuilding purposes, Meadows uses it frequently: try to keep your torso vertical, and hover off the ground for extra tension
Instead of getting super close to failure on squats you could also just do another set or two. And then do things lunges, hack squats, or landmine dip belt squats for your close to failure work. No landmine device no problem, use an old tennis shoes you won’t miss instead. I just place the heel of an old sneaker against a tree and shove the barbell into the shoe and do landmine work from there.
The saw horses I use are about the height of squat catches. A cheap pair might run you $30-50 if you don’t already have them lying around.
You can always slide out of a back squat rather than just dropping the weight on spotter arms. Or you could start front squatting and put pads under where the weight would fall if you drop it forward
The thing is, when you factor in wear-and-tear on the forearms, biceps and shoulder joints, and also the possibility of an acute distal biceps tendon injury, I for one am not convinced TB DLs are overall safer than freestanding squats. Anyone care to chime in on this?
Honestly sounds like you’re just looking for an excuse not to squat. If you hate squatting, so be it. But if your goals are bodybuilding, why are you ever planning to fail on a squat? And if it’s that much of a concern, front squats and zercher squats are very easy to bail on, and arguably better for quad and glute development anyway.
Luckily for us, the greatest exercise science mind of our time has already done the thinking for us so we don’t have to. The trap bar deadlift is the most dangerous of all because of the sagittal plane
One time, I did a trapbar deadlift, the weight came forward and I ended up carrying the weight out of the gym, across three highways, across a tiger enclosure and into the ocean where I stepped on a sharp shell. Would never have happened if I squatted for fahves
Have you tried a Platz Squat?
Heels elevated (think 45lbs plates but I’d you have crazy mobility it can be less) and almost touching, keep your body upright at the bottom, ass comes all the way down, knee comes very forward.
For sets of 15-20, these will humble the crap out of you. The weight won’t be enough to worry about if you get in trouble but the quad cramp might
I hate you! (Jk) Okay, not hate but possibly strongly dislike. I have been seeing Platz squats everywhere I go. Now, you too? It’s like the universe is trying to tell something
Yes, feel the hate then do them. That’s how they work.
Fine! But if I die it will be on you. 
Report back 
Each set needs to be challenging and higher rep though…
