Sorry to hear about your breathing problems, but I doubt it was because of the fumes alone from the vehicles, more likely from the brake dust and dust from the tyres, one of the leading Professors from the UN, pointed this out a few years back and actually advised cyclists to stay away from the roads
It is a bit weird that old cars are allowed into the LEZ and ULEZ zones as well as other vehicles that obviously pollute, yet penalise new cars and cars a few years old, this is why it is so hard to think when buying a new/second-hand vehicle, you just can't tell what is going to happen in the future.
About electric vehicles breaking down on motorways, we know we should always be aware of the range of the vehicle, my car has a computer that tells me, the problem with that is it is a computer and it bases its estimate on time and distance, I can get 70mpg on a clear motorway and 20mpg sitting in a slow moving traffic jam, so with one gallon of diesel I can travel 70 miles or 20 miles, therefor if I have half a gallon of fuel left after sitting in the jam, I know I can get 30-35 miles up the motorway, or to the first service station.and all that is if the fuel guage is correct, if my diesel car runs out of fuel at night, I put my hazard lights on, in an EV the battery is dead so I assume the lights wont work, unless it is fitted with a slave battery.
My assumption was made simply on the fact I am sure cars run out of petrol diesel on motorways, and I am sure the same will happen with EV's, which is why I do think most will be hybrids.