There are typically three Lanes in Lara Croft: Relic Run. Lara can run in either of these three lanes and change between them by swiping as long as there are no obstacles between them. If there is an obstacle coming up that Lara can not slide beneath or jump over, she has to change lanes or else she will hit the obstacle.
Powerups, Clues, or Relics are always located in one lane and never between them. On the other hand Coin Trails are often associated with a specific lane, but they also might start in one lane and end in a different one, with coins not clearly positioned in one or the other.
Sometimes there is only one lane, e.g. when there is a fork in the path, where Lara has to choose beforehand if she wants to turn left or right by stepping into the corresponding lane. At the beginning of Combat Sessions the path ahead also narrows to only one lane, e.g. at a door. Lara will automatically get into the middle lane here. This is also true for some ends of Slide Sequences in the Desert Ruins level - e.g. column jumping - or at the end of the ATV sequence in the Jungle Temple. Nonetheless the player should always be prepared to get into the right lane himself and not rely upon Lara to do it for him.
Swiping into a lane where there is no space for Lara might cause her to stumble. This increases the likelihood of hitting the next obstacle ahead while she is still recovering; e.g. in the Desert Ruins swiping into the stairs too late makes Lara stumble and run into the wall ahead.