Imagine yourself happily motoring down an Interstate highway when you have a sudden blow-out or other emergency situation. You roll (or coast) to the side, but you have limited ability to get too far off the roadway (because of obstacles or a curb), and you have to stop fairly close to the main-traveled portion of the roadway -- too close for comfort. Imagine yourself outside, trying to change that flat tire, next to the traffic lanes, people flying past you, less than 18 inches away and at break-neck speeds. Pretty scary, eh? I've seen cases where people who were trying to work beside the road underneath their vehicles lost their legs (or their lives) because they mistakenly swung them out too far toward the traffic lane. I have heard of highway patrolmen killed while making traffic stops, or while standing behind or beside their vehicles to investigate traffic collisions.
It used to be common to see virtually all approaching drivers give way to the left and give a stopped vehicle a wide berth. That person on the side of the road is in grave danger, but these days you rarely see other vehicles give them the safety cushion of an empty lane between them and the traffic. Sometimes, we don't see them soon enough to be able to switch lanes, or we find that another vehicle is already in the left lane, either passing us, or hanging right there with us and refusing to back off so we could merge in front of them (whether deliberately or not). One way we can prevent this kind of a bottleneck is to make certain to keep our vision up and down the road at least 15 seconds ahead or farther.
Sometimes we are just oblivious. I believe some drivers are simply unaware of the danger they are creating for the other guy. The second you see a vehicle on the side up ahead, whether it is a stranded motorist, a highway patrolman making a stop, or even a trucker doing a brake check in advance of a downgrade, PLEASE move left and give them "a brake." Do this whether you are on a controlled access highway or on a city street. Do it even if you can't change lanes completely -- just move left as far as you can. Your courtesy could save a life.
Keep the shiny side up!