Herança no Javascript usando new e Object.create

gistfile1.js

// http://jsfiddle.net/0s8kzoke/


console.log('----VEHICLE DEFINITION----');
function Vehicle(name, model, speedLimit) {
   // prevent the scope error when the programmer forgot the 
   // 'new' keyword before call the constructor.
   if (!(this instanceof Vehicle)){
      return new Vehicle(name, model, speedLimit);
   }
   this.name = name;
   this.model = model;
   this.speedLimit = speedLimit;
   this.speed = 0;
   return this;
}
Vehicle.prototype.getName = function getName() {
   return this.name;
}
Vehicle.prototype.getModel = function getModel() {
   return this.model;
}
Vehicle.prototype.getSpeed = function getSpeed() {
   return this.speed;
}
Vehicle.prototype.getSpeedLimit = function getSpeedLimit() {
   return this.speedLimit;
}
Vehicle.prototype.acelerate = function acelerate(speed) {
    console.log('Acelerating to - '+speed);
    if(speed > this.speedLimit) {
         throw new Error('You cant acelerate more than '+this.speedLimit);   
    }
    this.speed = speed;
}
console.log('----------------------------');

console.log('\n');
console.log('----TRUCK DEFINITION----');
console.log('----Truck extends Vehicle----');
// https://developer.mozilla.org/pt-BR/docs/Web/JavaScript/Reference/Global_Objects/Object/create
function Truck(name, model, speedLimit, maximumLoad) {
   // prevent the scope error when the programmer forgot the 
   // 'new' keyword before call the constructor.
   if (!(this instanceof Truck)){
      return new Truck(name, model, speedLimit, maximumLoad);
   }
   this.maximumLoad = maximumLoad;
   //Vehicle.call(this, name, model, speedLimit);
    Vehicle.apply(this, arguments);
}
Truck.prototype = Object.create(Vehicle.prototype);
Truck.prototype.constructor = Truck;
Truck.prototype.getMaximumLoad = function getMaximumLoad() {
   return this.maximumLoad;   
}

var truck = new Truck('Fast Truck VW', 'Serie 5', 180, '2 Tons');

truck.acelerate(100);
console.log('\n');
console.log('--- Specialist functions ---')
console.log('Maximum Load - '+truck.getMaximumLoad());

console.log('\n');
console.log('--- Inherited functions ---')
console.log('Name - '+truck.getName());
console.log('Model - '+truck.getModel());
console.log('Speed - '+truck.getSpeed());
console.log('Speed Limit - '+truck.getSpeedLimit());

console.log('\n');
console.log('--- Instance tests ---');
console.log('Truck is instance of Vehicle - '+(truck instanceof Vehicle));
console.log('Truck is instance of Truck - '+(truck instanceof Truck));

console.log('\n');
console.log('--- Has own properties tests ---');
console.log('Truck has maximum load property - '+truck.hasOwnProperty('maximumLoad'));
console.log('Vehicle has maximum load property - '+(new Vehicle('Vehicle test', 'Test', 230)).hasOwnProperty('maximumLoad'));
console.log('----------------------------');