Methodology for Using Advanced Event Data Recorders to Reconstruct Vehicle Trajectories for Use in Safety Impact Methodologies (SIM)

Figures & data

Fig. 1 SIM framework developed by the NHTSA (Carter et al. 2009; Funke et al. 2011).

Fig. 2 Scene diagram and scene and vehicle photographs prepared by crash investigator in NASS/CDS case 2011-11-148 (color figure available online).

Fig. 3 Precrash vehicle speed, accelerator pedal, and brake switch status for NASS/CDS case 2011-11-148 (color figure available online).

Fig. 4 Steering wheel angle of vehicle in NASS/CDS case 2011-11-148 (color figure available online).

Fig. 5 Process for simulating and validating vehicle trajectory models using advanced EDR data (color figure available online).

Table 1 Vehicle model parameters for Ford vehicles

Parameter (units)	2011 Fusion	2011 Escape
Overall length (m)	4.84	4.44
Overall height (m)	1.44	1.72
Overall width (m)	2.03	2.07
Wheelbase (m)	2.73	2.62
CG % back from front axle	40%	42%
Steering ratio	16.0:1	17.5:1
CG height (m)	0.547	0.680
Tire diameter (m)	0.657	0.735
Front cornering stiffness (N/rad)	38,762	53,218
Rear cornering stiffness (N/rad)	35,830	49,077

Table 2 Crash type, off-road travel, and ESC/ABS activation in advanced EDR cases

Crash type	Cases	Off-road	ESC active	ABS active
Straight crossing path	6	0	0	3
Road departure	5	4	3	4
LTAP/OD	5	0	0	1
Rear-end	3	0	0	0
Lane change	2	0	1	0
Opposite direction	1	0	0	0
Total	22	4	4	8

Fig. 6 Precrash speed, accelerator pedal, and brake switch for case 2011-11-148 (color figure available online).

Fig. 7 Precrash yaw rate for EDR and simulation for case 2011-11-148 (color figure available online).

Fig. 8 Steering wheel angle for case 2011-11-149 (color figure available online).

Fig. 9 Precrash yaw rate for EDR and simulation for case 2011-11-149 (color figure available online).

Table 3 Average absolute error in maximum yaw rate in simulations compared to EDR

Crash type	Average error (%)
Straight crossing path	18
Road departure	54
LTAP/OD	18
Rear-end	77
Lane change	43
Opposite direction	27
Total	38

Fig. 10 EDR recorded and simulation yaw rate for case 2011-11-149 with modified friction (color figure available online).

Fig. 11 Scene reconstruction for case 2011-11-148 (color figure available online).

Fig. 12 Trajectory of right front wheel with and without LDW for case 2011-11-148 (color figure available online).

Fig. 13 Scene diagram and vehicle damage in case 2011-48-111 (color figure available online).

Fig. 14 Vehicle initial position given final impact angles for case 2011-48-111 (color figure available online).

Fig. 15 Trajectory of left front wheel with and without LDW for case 2011-48-111 (color figure available online).

Carter , A A , Burgett , A , Srinivasan , G and Ranganathan , R . safety impact methodology (SIM): evaluation of pre-production systems . Paper presented at: 21st International Conference on the Enhanced Safety of Vehicles , Stuttgart , , Germany June 15–18

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Funke , J , Srinivasan , G , Ranganathan , R and Burgett , A . Safety impact methodology (SIM): application and results of the Advanced Crash Avoidance Technologies (ACAT) Program . Paper presented at: 22nd International Conference on the Enhanced Safety of Vehicles , Washington , DC June 13–16

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