I guess you missed the point of TFA. It is impossible for humans to perform the tasks these two persons were hired to do. 100% of people who attempt to do that job will eventually fail, likely sooner rather than later.
And they will continue to handle it with ease right up to the moment when they hit another cyclist.
What makes you so confident that the mere two years of running the program is enough to reliably calculate that number, when drivers like the one in the article managed to last more than a year until they got fired?