I'm not sure about that. Humans adjust pretty well and relatively quickly to changes when the incentives are right. Where I live I see people from many walks of life use buses or other forms or public transport without trepidation. Sure, it's possible that people will never travel in a 'normal' car with complete strangers, but if that's the case I'm sure we'll find ways to make 'cars' more amenable to co-traveling so that the significant advantages will be worth the slight inconvenience of traveling in one vehicle with strangers.