My Design Problem - 1 , A Man & Party Puzzle!!!! Tough One

A Man is Going to Party on Infinite length Road,So It Clear That You Don't know the starting point , ending point or length of the road he can start from any point in infinite length road & went to party & then came out from party,but her forgot where he parked the Car, Write an Efficient Algorithm that can solve his problem to find out the Car. Explain What data Structures You Will Use ?