PHP OOP with Abstract

Vehicle.php

<?php 

// ABSTRACT

ini_set('display_startup_errors', 1);
ini_set('display_errors', 1);
error_reporting(-1);

abstract class Vehicle{

    protected function initialSetup(){
        return $this->installChassis()
                    ->installTire()
                    ->installSteer();
    }
    protected function installChassis(){
        var_dump("lets installChassis");
        return $this;
    }
    protected function installTire(){
        var_dump("lets installTire");   
        return $this;
    }
    protected function installSteer(){
        var_dump("lets installSteer");
        return $this;
    }

    abstract public function setupSeats();
}

class Car extends Vehicle{

    public function __construct(){
        var_dump("Car created");
        $this->initialSetup();
        $this->setupSeats();
    }
    public function setupSeats(){
        var_dump("setup 7 seats for Car");   
    }
}

class Motorcycle extends Vehicle{

    public function __construct(){
        var_dump("Motorcycle created");
        $this->initialSetup();
        $this->setupSeats();
    }
    public function setupSeats(){
        var_dump("setup 2 seats for Motorcycle");   
    }
}

echo "<pre>";
$c = new Car();
echo "</pre>";
echo "<pre>";
$m = new Motorcycle();
echo "</pre>";



?>