SUBJECT: Rear Design Features of Vehicles: Part 1
TOPIC: Identifying Rear Design Features of Vehicles
OBJECTIVE: Identify by name the operating features found at the rear of selected vehicles and how those features operate.
TASK: Given pictures of the rear of vehicles, identify the design features by name and explain how the rear of the vehicle opens under normal conditions.

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Originally Published: February 2002

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Series Links: Part 2

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RONALD E. MOORE
University of Extrication Editor

Photo By Ron Moore

When the Ford Expedition liftgate is open, the pressurized lifting struts are visible. The liftgate has a center latch mechanism, located low along the floorline.

Photo By Ron Moore

The Dutch doors of this GM Safari minivan open up the lower portion of the rear of the vehicle. The half door on the driver’s side closes first and latches into the floor. The half door on the passenger’s side then closes and latches to the left half door.

Photo By Ron Moore

The tailgate feature shown on a GMC Blazer secures on two safety latches positioned along each side. The center handle that releases both latches to open the tailgate is mounted on the inside panel.

Photo By Ron Moore

Land Rover’s Discovery SUV is just one example of a vehicle with a large-size full door at the rear. This door pivots on the hinges visible near the passenger rear taillight area. Access pathways to reach the interior of a vehicle at a crash scene include doors, windows, windshield and the body of the vehicle. Side doors are used most often to reach those inside. If the vehicle is a sport utility vehicle (SUV), minivan, hatchback sedan or station wagon, access may be gained through the rear of the vehicle as well. With over 180 different makes and models of vehicles produced this current model year, it is important that responders recognize what design features are at the rear of a vehicle and how those features operate.At a crash, if access the patients or a pathway to extricate them will be through the rear of the vehicle, the first step is to understand how the features operate normally.

Vehicle terminology describing these rear design features is presented to assist in standardizing this aspect of vehicle rescue training:

• A lift window is a glass window, hinged at the roofline, that opens upward. This provides an opening of the upper half, 50%, of the rear. A lift window can be framed or unframed tempered glass. It is also called a lift glass by some automakers.
• A power window is a retractable window glass that lowers inside a tailgate. When lowered, the power window provides approximately a 50% opening across the top of the tailgate.
• A lift gate is a full-height one-piece unit, hinged at the roofline, that opens upward. This provides an opening of 100% of the rear of the vehicle.
• A tailgate is a one-piece unit, hinged along the floorline, that opens out and down. When open, a tailgate provides a 50% opening along the lower half of the rear of the vehicle.
• A half door is a small, hinged, half-height door that opens only the bottom 25% of the rear of the vehicle. A pair of half doors on a vehicle such as the Ford Excursion or a GM minivan is commonly called a pair of Dutch doors. These half doors are located below a lift window.
• A full door is a full-height, hinged rear door with a fixed window in its upper half. A full door opens outward on hinges that are mounted at the corners of the vehicle.
  

  If there is one single rear door at the back of the vehicle, the entire door will be hinged on one side and when open, provides a 100% opening at the rear of the vehicle. There may be a spare tire permanently mounted to the door or the tire may be on a mounting bracket that must be opened before the door will open. There can also be two full doors, each equal in size, hinged near the rear corners of the vehicle. This popular full door design requires each door to pivot outward as it opens. With both full doors swung open, 100% of the rear of the vehicle is accessible.

Photo By Ron Moore

The full doors on this Tahoe have fixed glass panels in their upper half. The passenger rear door opens first then the driver’s side full door can be released. GM refers to this design as the “cargo door” option.

Photo By Ron Moore

The Toyota 4Runner is an example of a vehicle with a power rear window that lowers into the tailgate. Once lowered, the tailgate can be opened outward.

Photo By Ron Moore

The lift window or lift glass of a Mercury Mountaineer shows how one end of the lifting struts are secured directly to the glass. If the glass were to break, a compressed strut will expand quickly.

Photo By Ron Moore

The tailgate of the Avalanche SUV can be opened and the bed cover removed. Inside the passenger compartment, the rear seats can be pivoted forward and the rear-window glass panel removed to transform the vehicle into a pickup truck.

A unique design used by Isuzu on its Trooper SUV uses two full doors. Each is hinged at a corner. The difference is however, that one door opens up a full two-thirds of the vehicle. The smaller companion door is hinged on the opposite side and opens up the remaining one-third of the rear area.

The rear of an SUV, minivan or station wagon is typically constructed of lightweight steel. If the liftgate or rear doors are not metal, they will be constructed of fiberglass or plastic materials.

The most unique rear features of any of the current models of SUVs are found on the 2002-model year Avalanche from Chevrolet. This vehicle is a cross between a pickup truck and an SUV. It can be “transformed” from a five-passenger SUV to a two-passenger pickup truck with an eight-foot-long bed. Referred to as a “midgate,” the moveable rear wall panel pivots forward to open up the rear of the cab.

Safety concerns with any lift window or lift gate include the presence of large and small pressurized hydraulic struts. The struts assist in opening a lift window or lift gate. These struts can fail explosively when heated during a vehicle fire. At a crash scene, rescue personnel must “disarm” these struts if rear glass is to be broken or the roof is to be removed.

If the vehicle has lift glass and the ends of the lifting struts are secured directly to the glass, the struts will expand quickly as the lift glass breaks. Rescuers should first break out side window glass and disarm the struts by prying them at one end. Then proceed to break out the lift window. If the vehicle has a rear lift gate and roof posts must be cut, the large hydraulic lifting struts must be disconnected before the roof pillars are cut through. Again attempt to disarm them by popping them off at one end. Some vehicle designs completely conceal these large struts, making it next to impossible to access them. In this case, open the liftgate and make the pillar cuts below the struts.

Part 2 of this series presents street-wise tips for identifying rear design features of a vehicle. Armed with this information, images of vehicles with the rear closed will be featured in a page layout format. Using this page, participants will be able to practice identifying the design feature by name and can practice explaining how the rear of the vehicle opens under normal conditions. Part 3 features guidelines on how to use these rear design features to your best advantage at crash scenes. This article will study real-world crash incidents where openings made at the rear of the damaged vehicle allowed responders to access or extricate their patients.