Motion Sickness [-10] is a mundane physical disadvantage. You cannot travel comfortably in any kind of vehicle, because their motion induces nausea. This disadvantage appeared in Compendium I for GURPS 3e.
This disadvantage represents a
severe case of the
real-world condition. You need to make a HT roll every time you start a journey in any sort of vehicle, and every subsequent day, for long journeys. If you succeed, you’re queasy and at -2 to DX, IQ and skill rolls. If you fail, you vomit (or some equivalent for your race) and are at -5 to DX, IQ and skill rolls. You can never learn any kind of vehicle-operation skill.
Not many real people seem to have a full case of this disadvantage, but a quite a few suffer from seasickness, airsickness and so on. There seems to be scope for applying limitations to model this. Drugs that might be mitigators (‑60%), at least for some forms, appear at TL6. Buying it off for one kind of vehicle could plausibly be a ‑20% limitation: after a couple of days being seasick, you could spend 2 points on this, for “Not seasickness”, and buying it for five types of vehicle would buy it off altogether. There are people who are fine “once they get their sea-legs” and then need time to re-adjust to land, which might be a -10% limitation.
There are rules for getting seasick without this disadvantage on p. 436 in Basic, and
Discworld applies them to travel by camel.
High-Tech and
Horror point out that Motion Sickness can be a side-effect of psychiatric medications;
Madness Dossier has drugs that do nothing else.
SEALs in Vietnam makes it a prohibited disadvantage, and
Steampunk 3 has Resistant to Motion Sickness, for the truly dedicated military officer.
I’ve never seen this disadvantage used in a game. I’ve been seasick at the -2 to DX/IQ level in real life, and had an inner-ear infection that gave me motion sickness while lying very still; it seems like something to reserve for very rough travel. Has Motion Sickness been important in your games?