Today if an asthmatic person uses asthma medicines most persons with asthma can live a normal life, and asthma is no danger when driving. Yes, you never get well from asthma, but you can live a life at least almost without symptoms if taking care and taking your medications. But that also depends on what you are sensitive to, and how severe asthma you got among other things. To be honest, medicines is no guarantee you do not get sick, but it sure helps.
Asthma can be a danger to the asthmatics life if not taking their medicines, not taking care and not getting help from the hospital when needed when having a bad asthma attack.
Generally it takes a while before the asthma attack gets hazardious to the asthmatic persons life. There are one kind of asthma attack that strikes immediately and is called Anaphylactic shock and is a very strong allergic reaction and is anaphylaxis associated with systemic vasodilation which results in low blood pressure. It is also associated with severe bronchoconstriction to the point where the individual is unable to breathe. Anaphylaxis can present with many different symptoms due to the systemic effects of histamine release. These usually develop over minutes to hours. The most common areas affected include: skin (80% to 90%), respiratory (70%), gastrointestinal (30% to 45%), heart and vasculature (10% to 45%), and central nervous system (10% to 15%). Luckily not the one I got though, mine generally sneaks up on me and gets worse by the hour. It gives me plenty of time to medicate and get to the doctor if needed. So it is no danger to driving cars, bus, truck or any kind of vehicle. It is only to park the car and go to the doc. But I never drive when I am really ill, one should never drive feeling ill whatever illness.
Normally it starts with feeling bad. Heavy breath, cough, tight chest and trouble breathing. One should take ones medicines at ones when feeling it coming. Then it may or probably ends. It is here the difference is. If one not got medicines or get treatment with the hospital then it can get life threatening. And the hazard is that the lungs can not take up as much air and oxygen that the body need to function. Waiting to long (can vary but normally up to several hours) and if the attack do not blow over by itself (normally it do not go over by itself), and not seeking treatment asthma can suffocate the person having it.
Treatment of acute symptoms is usually with an inhaled short-acting beta-2 agonist (such as salbutamol). Symptoms can be prevented by avoiding triggers, such as allergens and irritants, and by inhaling corticosteroids. Leukotriene antagonists are less effective than corticosteroids and thus less preferred.
In 2009 about 300 million people were affected of asthma worldwide, and the same year asthma caused 250,000 deaths globally. Despite this, with proper control of asthma with step down therapy prognosis is generally good. But of course one death is one to many. It is mostly those that do not have medicines and care available at hospitals, or can not afford it that is in risk to die from it. But also if you do not get treatment in time it can be a danger.
I have not even been close to die from it, I got the good kind of asthma if ther is one, and I listen to my body. But it is a rather unpleasant feeling not getting air and not getting oxygen. After some hours one can get dizzy, out of power, getting tired and feeling it coming – the danger that is. The most creepy kind of attack I had was the one sneaked up on me and because of the oxygen drop I got sleepy. I got so less oxygen that I was afraid to pass out. I went to the hospital straight away. Another kind of attack is very brutal. One get so hard cough and shortage of breath that it is brutal. I have had that brutal one also. It was so brutal that I got physical pain in my muscles in my chest area and had to hold my body with my arms because of the pain. In any case one should go to the hospital without delay. It is not a good thing passing out because of not getting enough oxygen. If that happens and you are alone, and do not get help, then the danger of dying is a fact. It may take a while, maybe a long while, but is a possibility and not to mess with.
So taking ones medicines are very important. But it does not stop there. You should avoid everything you get sick from in the first place, and everyone in a community should drop the use of the most common allergens and irritants that can threat a asthma sick persons health.
Note! If you got asthma with anaphylactic shock that is a very strong allergic reaction you are more likely to pass out in a few seconds. Always carry your needle/pen with you, and instruct your friends on how to use it. Asthma without anaphylactic shock builds up over time and it takes minutes to hours to get sick. It normally starts with a smaller reaction that builds up and get worsen by the hour. The asthma without anaphylactic shock takes longer time to get really ill from, you should as well treat your asthma for what it is. An illness that must be cept in its place, so to speak. Do not ignore small reactions, if you do they grow worse over time. Inhale your medicine and stay away from what make you ill, and then you can avoid getting more ill. That is how it works. Get fresh air and medicate, be well. If you do, you might not have to get really ill. :)
Source: Wikipedia and my own experiences.