@Ereshkigalangcleg
There is rarely any coverage of those deaths, so we have a skewed view of the relative risks.
Although I agree with a lot of your points, it does seem like you're using statistics in a misleading way, similar to the "35 year life expectancy" for MTF trans people. As NecessaryScene deduced, is it the case that your "15 or 30 minute life expectancy" is based on average time for all deaths caused by stopping on the hard shoulder, or is it on every person in a car that has stopped on the hard shoulder whether or not there was an accident and whether or not the people were safely recovered?
I am quoting stats that I was taught as part of emergency services training and that, as other posters have noted, are widely available online. What I was taught was that, if you stop on the hard shoulder and do not leave your vehicle, you will on average survive 15 mins (at the time I was trained, now 30 mins) until you are hit by another vehicle. This is from police data. Clearly they don't know - so cannot include - every single time that someone stops anywhere in the UK. But very large stretches of the motorway are under camera surveillance, so they have a large and robust sample, on which to base this. They have thousands of stretches of hard shoulder under continuous surveillance so have figures on all stops in those areas, however brief.
I find it fascinating that so many people are so invested in disagreeing with this. So far, other than the update about the average now being 30 minutes (which I accept) no one has posted any data showing a different figure. I'm just told that it's bollocks and that I don't understand life expectancy. I'd suggest the issue is more that people underestimate the risk. Think about the M25, for example. At its busiest points, 200,000 vehicles use it every day. Obviously they are not evenly distributed throughout 24h, but for simplicity let's estimate that two thirds travel between 7 am - 7 pm, and that they are evenly distributed during that time. That would mean 11,000 vehicles per hour. If you breakdown on the hard shoulder, 2,750 vehicles will pass you in 15 minutes. Is it really so hard to believe that one of them is likely to hit you?
And yes, of course, the M25 is a very busy motorway, but I have never suggested that the risk is the same, no matter how busy the motorway is. Of course, busier stretches are more dangerous and depress the average survival.