Lane design: How I optimized a 3 lane system

Originally the runner randomly spawned new tiles. We found that rather difficult to maintain a steady difficulty for children to play at. So i was tasked with created a lane system and track. Here you can see a outline of the whole track in the white line

Initially i attempted making three separate splines, what i found out is that each spline was slightly different so 500 units on one of them could mean 1000 units on another. So i came up with the track rider system.

While playing the bar, as seen in the image above, dictates the final forward vector that George is at. On that bar are three attached markers. Which on a left or right press George will move to. This creates a simulation of 3 lanes while really having 1!