But because of the rotation of the Earth and in fact the whole Galaxy in the meantime, the vertical component of the ravine became the horizontal component of the road :)
If we assume time travel is possible which is quite a leap already, why do people fixate on things things having to keep their fixed point in space relative to... well.. relative to what? Frames of reference can really complicate this.
Perhaps time and gravity are related in a manner that means as an object travels through time it maintains position relative to gravitational influences (and local ones affect it far more than others due to the inverse-square relationship) and maybe the effect is strong enough on each part of the travelling body that it maintains orientation relative to those gravitation influences too (so the car not only stays on the road but conveniently wheels-down as well).
Perhaps time and gravity are related in a manner that means as an object travels through time it maintains position relative to gravitational influences (and local ones affect it far more than others due to the inverse-square relationship) and maybe the effect is strong enough on each part of the travelling body that it maintains orientation relative to those gravitation influences too (so the car not only stays on the road but conveniently wheels-down as well).