Former Automotive Engineer Explains Audi A4 Clamshell Hood Design - What Makes it so Great?

Here's a brief video explaining the Audi A4 clamshell hood design from a former automotive engineer who worked on body closures (hood, doors, liftgate/trunk) at a large OEM vehicle manufacturer. In short, the clamshell hood design creates a cleaner look that allows the hood to fender cutline to blend seamlessly into the design language, particularly with the long horizontal character line that is often stamped into the vehicle fenders and doors from front to back along the vehicle's side profile. In addition, the clamshell hood is more pleasing to the eye of the driver from behind the wheel, with no visible gaps or cutlines that mar the aesthetic while driving the car. In addition, the clamshell hood allows the hood to "shingle", or overlap, the front side fenders so that a large dark gap is not seen between the two body panels when the car is viewed from the side. Furthermore, the clamshell hood cutline being positioned farther down along the side of the vehicle essentially directs air towards the side-mounted rearview mirrors that manage the turbulent airflow to smooth it out and reduce wind noise, instead of this turbulent air coming through the hood cutline straight up onto the windshield. This not only reduces wind noise, but also reduces hood flutter at high speed, which is caused by excessive high pressure and airflow under the hood that can make the hood appear to bounce when viewed from behind the wheel while driving at high speeds. The clamshell hood also eliminates the driver's visible reference point to compare the hood height to the height of the surrounding front side fenders, so that fit and finish is better able to be controlled during manufacturing, hood and front side fender manufacturing and assembly variation can be hidden to the driver, and so that hood flutter, should it occur, will be more difficult to notice.