Photo By Ron Moore The polymer plastic fender of this Saturn cracked on impact, making it difficult for rescuers to force entry to a jammed rear door.

Ever since the first Saturn owners took delivery of their cars in October 1990, fire and rescue responders have faced greater odds of dealing with plastic-bodied vehicles in fire and crash situations. Estimates are that more than two million Saturns are on the road today in North America. Saturn now offers a number of vehicle designs including two-door, three-door and four-door sedans, and a four-door station wagon.

New for the 2002 model year, is Saturn’s first SUV called the Vue. In addition to this new four-door sport utility vehicle, the 2003 Saturn lineup will introduce the Saturn Ion sedan, coupe and station wagon models. The Ion sedan will have four front-hinged, forward-opening doors. The 2003 Ion Quad Coupe, however, will be a four-door vehicle, but both rear doors will be of a rear-hinged, rear-opening design.

Photo By Ron Moore The hood of this Saturn is sheetmetal. It bent, but stayed intact during this collision, held on by just the one remaining hood hinge.

We’ll study the extrication challenges of Saturn vehicles by first looking at important structural design elements, then discuss the plastic body materials and finally look at the special safety systems present on current model Saturns. In Part 2 of this series we’ll look at real-world incidents involving these vehicles.

Saturn vehicles are all constructed around a welded steel spaceframe design, which consists of a steel cage surrounding the passenger cabin. Saturns are front-wheel-drive vehicles with rack-and-pinion steering and McPherson strut front suspension. What has always been a unique component of all Saturn vehicles is the use of polymer body side panels for doors, fenders and bumpers. The roof, hood and trunk lid are conventional sheetmetal panels. The paint on the sheetmetal portions of the vehicle blends in perfectly with the plastic polymer body panels. At a crash scene, it is extremely difficult to tell whether a body panel of the vehicle is steel or plastic.

Photo By Ron Moore This auto show cut-away clearly shows the collision beams inside each door.

Saturn recently improved its side-impact crash performance by strengthening the spaceframe body structure through the use of a new honeycombed composite plastic material and an expansion adhesive. The honeycomb materials are placed inside the hollow spaceframe structure at strategic pillar joints during the manufacturing process. When the freshly painted vehicle is placed in the paint ovens, this special material expands and swells up inside the hollow spaceframe. This inner reinforcement material stiffens the spaceframe structure at these joints and hinge points. There are also steel collision beams inside the doors – a horizontal one inside each front door and an angled collision beam inside the standard rear door.

Photo By Ron Moore The passenger frontal airbag on this Saturn is concealed beneath the upholstery of the instrument panel. Upon deployment, the airbag cover tears up through the dash.

Another recent safety enhancement to the L-Series Saturns includes a new headlight warning system. When a crash causes any of the frontal or side-impact airbags to deploy, the headlamps are set to continuously flash as a distress signal and the interior dome lamp will automatically come on to aid in exiting the vehicle. Saturn customers now also have the option of OnStar on some models.

The new third-door design, available on Saturn vehicles since December 1998, takes the two-door coupe and converts it into the first-ever three-door sedan. The rear-hinged, rear-opening third door is on the driver’s side. The third door provides the latch pin to hold the driver’s front door closed. The front door must be opened first before the handle of the third door is accessible along the edge of the door. The third door latches at two points; into the upper roof rail and at a latch point on the rocker channel.

Photo By Ron Moore The outline of the third door is clearly visible on this 2001 model Saturn SC-2 sedan.

In a head-on collision, there are dual frontal airbags and energy-absorbing knee bolsters in the dashboard for the driver and right-front passenger. An interesting design, called a “rear seat anti-submarining ramp,” minimizes the rear-seat passengers from sliding forward in a frontal crash. The metal support under the rear seat cushion is actually angled upward like a ramp to minimize occupant forward travel. If a rescue crew has to force access to the interior of the vehicle through the trunk, the rear seats are designed with 60/40-split folding rear seatbacks.

Photo By Ron Moore The two latches of the third door are visible; along the roofline and on the rocker channel. The safety latch for the front door and the third door handle are visible along the edge of the third door.

First introduced with the 2001 model year, Saturn vehicles now may be encountered with roof-mounted side-impact airbags. In a side-impact collision, the head curtain airbag drops to cover the side window areas on the impact side. The airbag curtains will deploy on both sides of the passenger compartment in certain collisions. The head curtain airbag system is currently a standard feature on all L-Series models. The stored gas inflator module for each head curtain is secured to the inside of the rear C-pillar.

Photo By Ron Moore This artist’s sketch depicts what the roof-mounted side-impact airbags would look like when deployed. Each head curtain airbag is designed to protect both the front-seat and rear-seat occupant on the impact side of the vehicle.