Protected modifier usage

driver.kt

fun main() {

    val car = Car()
    // although it is protected inside vehicle class while overriding it 
    // in the subclass we marked as public hence it is accessbile
    car.start()

    //car.engineStart() // not accessible since it is protected inside the car class
}

vehicle.kt

abstract class Vehicle {

    protected abstract fun start()

    protected fun engineStart() {

    }

}

class Car: Vehicle() {
    public override fun start() {
        engineStart()
    }
}