The Insight's futuristic, aerodynamic shape is both distinctive and functional. The low, rounded nose is designed to part the air with a minimum of turbulence, and also affords the driver and passenger an unobstructed forward view. Louvers in the cooling-air inlets have been carefully designed to minimize turbulence. The headlight assemblies blend smoothly into the contour of the fender, and the fenders have large-radius curves in order to minimally disturb the air flowing around them.
To minimize frontal area and drag, the windshield is steeply raked, and its edges blend smoothly with the sides and cabin roof. The trailing edge of the hood and cowl are shaped to smoothly divert airflow over the windshield wipers.
The roof tapers to the rear of the vehicle in a teardrop shape. The cabin's ample glass area affords good outward visibility in all directions, and also lends a light, airy feeling to the interior. The glass rear hatch has an additional panel that lets the driver see what is immediately behind the vehicle - an especially useful feature when backing up.
The Insight's gently curved sides and wheelwells are also designed to minimize air turbulence. The plastic-resin front fenders extend downward below the centerline of the wheel and incorporate a small air dam in front of the wheel. To further minimize turbulence, the trailing edge of the wheelwell is inset and faired into the body. Disc-shaped aluminum wheels also help smooth airflow around the wheelwells.
The importance of minimizing air turbulence at the rear of the vehicle is also evident in the Insight's design. Since a teardrop shape disturbs airflow around a moving body the least, the rear of the Insight narrows and tapers in cross-section. Even the rear-wheel track is narrower than the front, by 4.3 inches. The rear wheels also sit in enclosed fairings. Special aerodynamic skirts further smooth the airflow around the wheel openings.
At the very back of the Insight, the teardrop shape is abruptly cut off in what is called a Kamm back (a distinctive design feature also shared by the Honda CRX). The Kamm back takes advantage of the fact that beyond a certain point there is little aerodynamic advantage to be gained by rounding off or tapering and extending the tail section of an automobile, so one might as well abruptly truncate it at that point. The Kamm back is a design feature that has been incorporated into many high-performance automobiles and racing cars over the years.
Another important aerodynamic detail that greatly contributes to the Insight body's low coefficient of drag is the careful management of underbody airflow. The Insight body features a flat underbody design that smoothes airflow under the car. Areas of the underside that must remain open to the air, such as the exhaust system and the area around the fuel tank, have separate fairings to smooth the airflow around them.
In order to minimize air leakage to the underside, the lower edges of the sides and the rear of the body form a strake that functions as an air dam. At the rear, the floor pan rises at a five-degree -angle toward the rear bumper, creating a gradual increase in underbody area that smoothly feeds underbody air into the low-pressure area at the rear of the vehicle.