This piece can be used on a 2 lane digital track or (with 30351) can be used to expand your 2 lane digital 132/124 layout into 4 lanes.
Please note when expanding from 2 - 4 lanes and using a lap counter, all cars will need to pass thru lanes 1 and 2 (w/the black box or control unit) in order for the laps to register. You can take a look at the 3rd and 4th image to view the expansion.