still, though ... the logistics of entering a freeway the wrong way are quite impressive. you go down a ramp and then you are suddenly expected to merge right ... and there's another carriageway to the right of you?
if this doesn't instantly feel viscerally wrong, you should not be driving.
Of course you are correct - but a driver under the influence of something (or just plain fatigued) - might not make draw the same (rational) conclusion that you did above - especially late at night with light traffic volumes, when these types of wrecks seem to happen.
In such instances, we might be preventing at least some
wrong-way wrecks by using Caltrans-style signage (and arrows painted onto the pavement in the direction of legal travel) to deter wrong-way entry. See
Figure 28-18 (CA) in the California MUTCD
Both Maryland and Virginia also use "plowable" recessed in-pavement reflectors (i don't know if Caltrans uses these), which are designed to return a red glow if a vehicle drives the wrong way down a one-way road (but many drivers may not be aware of this - and an impaired driver might not notice anyway).
Then there's the matter of driving on a high-speed one-way roadway and seeing something approaching at a high speed, and not moving out of the way. I don't mean to blame the not-at-fault victim, but by looking at the road ahead, it is possible to see a vehicle coming the wrong way (at least if it has its lights on), though the time to react (including pulling over to the right shoulder to get out of the way) may be small.