Additionally, it's probably a reasonable assumption that even in cases where a front-seat passenger is present, the majority of impacts would be driver side. I

Additionally, it's probably a reasonable assumption that even in cases where a front-seat passenger is present, the majority of impacts would be driver side. I thought about the following cases where you might encounter this type of impact: 1. Driver is not controlling the car properly (asleep, drunk, etc.) and leaves the carriageway and impacts some road furniture, etc. - in this case, single driver likely has around 50/50 chance of going left vs right, but an accompanied driver is less likely to have this type of incident (passenger can shout to wake the driver, reach for the wheel, etc.). As a result, total fatalities from this collision mode would probably be significantly higher for drivers than passengers. 2. Driver understeers around a corner. In this case, understeer would be more likely on a smaller radius corner than a larger one. As the drivers' side is closest to the other carriageway, this means that the driver would already need to be on the widest part of the curve in order for the impact to be on the passenger's side. This likely reduces the frequency of oversteering from the outside of a turn - although as a secondary consideration, it probably implies higher speed, and so potentially higher fatality rate. Therefore, as more oversteer-related incidents would happen from the inside of the curve, the driver is more likely to be impacted. 3. Impact occurs during overtaking. In this case, we assume the driver is in the opposite carriageway. Oncoming traffic is likely to evade, and during an overtaking manoeuvre, it is likely that evasion into the driver's original lane is not possible due to other traffic. As a result, both our driver and oncoming traffic are likely to try to evade off the carriageway (onto the hard shoulder, grass verge, etc.) Considering that this is a small overlap test, it would imply that evasion has been at least partially successful, implying reduced speeds, etc. It's probably not particularly more likely that either driver or passenger is subject to this impact. I couldn't think of any other illustrative cases, but it does seem that the even considering that passengers are not present in all cases, the individual risk to a passenger is lower than the risk to a driver when there is one present.