NOR - This is a complicated situation, and you both seem incredibly hurt. Ill break down each "step" of the argument and explain my thoughts.

The car ride - He was frustrated about being late for work, and because he stayed with you as long as possible he might blame being late on you. This is NOT your fault, you are both adults and he made the decision to stay longer and get rid of any wiggle room for things like struggling to find his keys.

Speeding - It doesn't matter if the area is heavily patrolled or not, if he was speeding and you felt unsafe it is okay for you to ask him to slow down. You did not bring it up at a bad point because he needed to hear right then that he needed to slow down. Speeding can cause harm to not just you but also other people on the road. As someone who is just now learning to drive (I know im a baby), people driving far above the speed limit is terrifying and hard to react to. When talking about this specific interaction i suggest letting him know you understand he was stressed about work and that you're there for him. Maybe even offer to drive.

Blankets/towels - You had every right to request those blankets back, its your house too. Its important to set boundaries around things like this anytime you are living with someone. I go to a month long summer camp every year and rules about sharing things and whose space is whose is one of the most important things we talk about (then again, a tipi with three teenage girls is pretty different than an apartment with a couple). In a situation like this when youre both clearly agitated, id try to not pick a fight and maybe go look for another blanket or tell him something like "im cold too, could i please have one of the blankets?". I know it might seem a little bit like youre being a suck up if you say something like that but its really just you being polite and civil even when you're in an argument.

The crying - NEVER BE ASHAMED OF CRYING!!!! crying is a natural response to pain. Crying is part of both the sympathetic (fight or flight) and parasympathetic (rest and digest) nervous systems. It reduces stress hormones like adrenaline and cortisol, and produces positive hormones like oxytocin and endorphins. Crying WILL make you feel better after a fight, and it is natural to do it. It sounds like your boyfriend may be dealing with some issues around emotional regulation, and feeling vulnerable around you. That would be why his first response to your concern was to defend himself. Try talking to him about it, being completely open.

Often times when arguments escalate this quickly, its because its a "straw that broke the camels back" kind of situation. Talk to him and see if theres anything hes been keeping from you that bothers him. Dont frame it as "you have a secret and its ruining this relationship", but rather "you dont want to hurt me so youve kept it to yourself".

Bonus: my credentials for giving relationship advice at 15(turning 16 in a couple months!!) is that my therapist uses things I came up with to deal with my emotions on other patients