As part of my experimentation with 2.4 Ghz slot car conversions I am using both the 1965 Eldon Selectronic and 1973 Eldon/Cox Super Scale double lane change track sections.

As shown in the pic the 1965 lane change mechanism design easily lends itself for a smooth lane change with steerable RC car by modification of the lane change "insert". The 1973 section can be similarly modified.

Simply add a smooth vertical wall on either side of the slot glued to a flat piece of plastic. The car's steering capability can then be used to choose the car's direction.