Field Accident Data Analysis of 2 nd Row Children and Individual Case Reviews

Field Accident Data Analysis of 2 nd Row Children and Individual Case Reviews David C Viano, Chantal S Parenteau ProBiomechanics LLC SAE 2008-01 01-18511851

CSS 38% U 50% Front 45% Background Children <10 yo in Fatal Crashes B 12% U 34% Legend: U: Unbelted B: Belted CSS: Child Safety Seat Side: 32% (left & right) CSS 57% B 9% CSS 34% CSS 56% U 37% Rear 10% B 4% U 62% B 7% Gotschall NHTSA 2001

Background Government and non-governmental organizations have recommended placing children in the back seat of vehicles. The recommendation has changed parent s s behavior. More children are riding in back seats to avoid interaction with a deploying passenger airbag. In 1996, 30 children were fatally injured by a passenger airbag and only 3 in 2006. Our questions are: What are the injury patterns for 2 nd row children by crash and vehicle type and what are the priorities for future safety improvements for children riding in the 2 nd row?

Background Children 0-70 yo Fatality Risk by PDOF # FARS deaths/# NASS MAIS=0-6 0.95% 0.11% 0.65% 0.04% 0.41% 0.17% 8.06% 0.03% 2.40% 1 st Row 1.00% 0.64% 0.03% Overall 0.50% 1.22% 0.22% 0.12% 0.02% 0.21% 0.07% 0.02% 0.30% 0.06% 0.07% 0.06% 0.03% 0.08 % 0.09% 0.05% 0.05% 1.53% 0.87% 0.62% 2.48% 0.45% 1.34% 0.46% 1.35% 0.35% 3.04% 0.18% 5.88% 2 nd Row 2.74% 0.27% 0.44% 1.06% 1.23% 0.25% 0.48% 0.83% 0.12% Overall 0.29% 1.11% Overall 0.27% 2.07% Overall 0.32% 1.35% Traf Inj Prev 9(3) 2008

Study Objectives One objective of this study was to analyze field accident data for 0-7 year old children in the 2 nd row by vehicle and crash type, irrespective of restraint use. Another was to review individual rear and frontal impact cases from the NASS-CDS electronic files to better understand injury mechanisms of young children in the 2 nd row.

Methods: Field Data Data was obtained from NASS-CDS for calendar years 1991-2005 for cars, SUVs and vans. Accidents were selected based on 2 nd row occupancy in towaway, light vehicles with model year 1990 or newer. The data was weighted to represent a national sample. Impact types were defined as: Front impacts: towaway vehicles with front impact location (GAD1= F ) ) and no rollover (rollover 0). Side impacts: towaway vehicles with side impact location (GAD1= L or R )) and no rollover (rollover 0). Rear impacts: towaway vehicles with rear impact location (GAD1= B ) ) and no rollover (rollover 0). Rollovers: towaway vehicles with a rollover (rollover > 0).

Results: Field Data 0-7 year old Children 2 nd Row Front 30% Rear 18% Rollover 17% Front 30% Car MAIS 3+F Side 35% Side: 31% (left & right) Rollover 61% Front 21% Side 9% Rear 9% SUV Rollover 23% Rear 0% Front 44% Van Rear 15% Side 33%

Results: Field Data Risk MAIS 3+ F 5% 4% 3% 2% 1% Front Risk MAIS 3+ F 5% 4% 3% 2% 1% Rear 0% -1% LV Car SUV Van 0% -1% LV Car SUV Van Risk MAIS 3+ F 5% 4% 3% 2% 1% 0% -1% Side LV Car SUV Van Risk MAIS 3+ F 13% 11% 9% 7% 5% 3% 1% -1% Rollover LV Car SUV Van

Methods: Individual Cases Individual rear and frontal impact cases were reviewed from the NASS-CDS electronic database. Two searches were carried out for seriously injured children (MAIS 3+F) aged 0-70 7 years old in the 2 nd row: 1) Rear crashes: 19 children were seriously-fatally injured in 16 rear impacts in NASS-CDS 1997-2005. 2) Frontal crashes: 54 in frontal impacts in NASS-CDS 1997-2004. 28 cases with serious-fatal head or spine injury were downloaded. The head and spine have the highest associated HARM for critical injury.

Rear Case: 1998-45 45-108K V2 (1992 Toyota Corolla) was merging onto the interstate and lost luggage off the roof. V2 stopped and backed up. V2 was hit in the rear by V1. 9 2 nd row intrusion The 3 year old female in the left rear seat received fatal head injuries by contact with the B-pillar.

Rear Case: 2003-11 11-193B193B V2 (1995 Saturn) was stopped 50 ft from the intersection waiting for traffic at the light ahead. V1 impacted the back of V2. 12 2 nd row intrusion A 5 year old child was belted in a booster seat in the second row left. She was fatally injured. Some injuries were caused by the high-back booster reinforced by rear intrusion causing a crushed chest against the front seatback.

Rear Case: 2005-74 74-144 V1 (2001 Chevrolet Cavalier) was impacted in the left rear by a 2005 Kenworth, which pushed V1 forward and into a counter-clockwise rotation. 30 2 nd row intrusion The 3 year old left rear male was restrained in a child safety seat. The child had a skull fracture and AIS 5 brain injury from contact with the front seatback.

Intrusion Timing Intrusion occurs early during the collision forces and vehicle acceleration. Intrusion occurs before much vehicle motion, front seatback rotation or front occupant movement. Intrusion pushes the 2 nd row occupant forward into structures in front of them. from SAE 2008-01-0188

Rear Case: 2002-075 075-137 V2 (1996 Subaru Impreza) was approaching an intersection and slowed. V1 hit the back of V2. No 2 nd row intrusion During the impact, the driver s seat moved rearward. A 2 year old male was in a child safety seat in the left rear. He received an AIS 3 facial fracture from the front seatback. The restrained driver of V2 was not injured.

Summary: Children Injured in Rear Impacts 68.4% of the electronic cases (13 of 19) had intrusion pushing the child forward into the back of the front seat, B-pillar or other front structures. Intrusion occurred early during the collision forces and vehicle acceleration. It occurred before substantial rearward rotation of the front occupant s s seat. As the front occupant is being accelerated forward, they load their seatback rearward. If the child is near or against the seatback, they are subjected to forces of intrusion pushing them forward and rearward loads from seatback rotation. There was only one NASS-CDS case (5.3%) where the front seatback rotated rearward contacting a 2 nd row child causing a facial injury.

Frontal Case: 1998-012 012-131J 131J V1 swerved around a vehicle that turned right in front of him. V1 then hit V2 (1995 Chevrolet Lumina) head-on. The 6 year old male in the left rear was unrestrained. He impacted the front seatback and experienced an AIS 4 brain injury. See also SAE 2008-01 01-14851485

Frontal Case: 1999-045 045-190B V1 (1999 Dodge Caravan) was northbound and V2 (1987 Ford Escort) was southbound. V2 lost control as it exited a curve. V2 over-corrected and crossed onto the northbound lane. V1 struck V2 head-on. The 2 nd row right child was a 4 year old female improperly lap-shoulder belted with the shoulder portion worn behind. She had an AIS 5 cervical spine injury by contact with the front seatback.

Frontal Case: 2001-075 075-74B74B V1 (1995 Oldsmobile Silhouette) drifted over the double yellow line into on-coming traffic striking V2. The 4 year old female in the left rear was unrestrained. She impacted the front seatback and experienced fatal brain injury.

Frontal Case: 2002-076 076-097A 097A V1 (2001 Chevrolet Cavalier) crossed the centerline to avoid an impact with a car in front. V1 struck the front of V2 in an offset configuration. The 11 month old right rear male was in a rear-facing CSS. He was partially ejected when the CSS harness failed to hold the occupant in the seat. The CSS was not held in place by the installed lap-shoulder belt. The child was hospitalized with skull fractures and brain injuries AIS 5 from contact with the front seatback.

Summary: Children Injured in Frontal Impacts In 46.4% of cases (13 of 28), injury occurred by the child impacting the seatback (8), B-pillar B (3), side interior (1) or center console (1) in front of them. These contacts can occur irrespective of restraint or child safety seat use. In 21.4% of cases (6 of 28), the injury source was the child safety seat. Lack of proper seatbelt or CSS use is a key factor in the frontal injury of young children. FMVSS 201U added contact points above the beltline on the A-pillar, B-pillar B and roof area to reduce the risks of head injury, primarily to adult occupants. Children often strike the seatback, B-pillar B and interior below the beltline. Stiffening the front seat would increase the force for yielding forward by child contact. This would increase injury risks.

Children Behind ABTS in Front Impacts 33.5 mph frontal sled test with an unbelted 6 yr Hybrid III seated behind a production ABTS (All Belts to Seat) seat. The unbelted child dummy in the 2 nd row had: HIC = 5,307 Chest 3ms acceleration = 99.4 g Ncf = 2.56 HIC was 7.3-times above tolerance Chest acceleration was 1.1-times tolerance Neck was 2.56-times tolerance

Overall Conclusions The majority of injury in rear impacts is associated with intrusion pushing the child forward into structures in front of them (front seatback, B-pillar B or other structures). Intrusion occurs early before much front seatback rotation. Seatback rotation is not a factor. The majority of injury in front impacts is associated with impact to structures in front of the child (front seatback, B-B pillar or other structures). Efforts to increase proper seatbelt and CSS use are needed. Stiffness of the structures below the beltline is a factor in the injury to young children. Applying a modified FMVSS 201 to structures hit by young children should be considered. A wrap-around child shield may be beneficial in the most severe rear crashes.