Techniques for determining a location for a vehicle to join a route structure are discussed herein. A vehicle computing system may operate the vehicle off the route structure according to an inertial-based reference frame. The vehicle computing system may determine a lateral distance of the vehicle to a route of the route structure and an angular difference between a heading of the vehicle and a direction of travel associated with the route. The vehicle computing system may determine a location to rejoin the route based on the lateral distance and the angular difference. In some examples, the vehicle computing system may determine the location based on a sigmoid function. The vehicle computing system may determine a vehicle trajectory to the location and may control the vehicle to the route based on the vehicle trajectory and the inertial-based reference frame.