Protection against weather and a level of security
							                                
                                        
                                    
							                        
                    
                            Only for advertising space
							                                
                                        
                                    
							                        
                    
                            To increase aerodynamic efficiency
							                                
                                        
                                    
							                        
                    
                            Solely for aesthetic purposes
							                                
                                        
                                    
							                        
                     
	 
	