On the flip side the smell and eye watering and lung burning is so strong that even the smallest leak cannot go undetected for a second. There can never be any such cloud except in the case of an accident. At all other times the tiniest leak anywhere will make everyone scramble and shut valves off.
I do believe this. I don't know what their plans are for making the mass almost uncontrollable distribution and handling infrastructure safe, but I can't believe it can ever be as safe as gas or diesel. I mean you can carry enough energy to move tons of weight for dozens of miles at high speed and up hills, in a plain open pail like water, or a milk jug, and drop it, spill it all over yourself, throw a lit cigarette right into it... And it doesn't explode or anything.
I can imagine ways to make the car tank reasonably safe in car crashes, just by making the tank good and strong and protecting it along with the passengers such that anything bad enough to hurt the tank already killed everyone anyway, and anything short of that, there could be a pretty simple mechanical auto shutoff inside the tank that seals up all the pipes from the inside and the only thing to escape will be the contents of the lines, and the lines can be thin. So I'm actually not that worried about car crashes.
But the number of infrastructure bits that all need to be mechanically sound and properly maintained and not old, bent, chewed up or worn seals, corroded, abraded, rusted, dirty with sand, ice, hit with a back hoe, ruptured from ice or tree roots, etc etc...
If it's a calm humid day, the ammonia will combine with moisture to form a vapor that's heavier than air, so it will settle to the ground instead of dissipating. That means if you have even a tiny leak from the pump nozzle, over time it would accumulate in low-lying areas like basements.
