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From page 46... ... Table 10 presents FARS data for the 1994–99 period concerning how often "Curb" was noted as the FHE in fatal crashes on roads with speed limits of 40 mph (65 km/h) or greater for all crashes and SV fatal crashes. Read the entire page →
From page 47... ... If one included all speed limits, and thus urban streets where curbs are standard, the percentages for both fatal crashes and total crashes would increase, but not to a large extent. For example, in the 1999 FARS data, there are a total of 599 fatalities in which curb was the FHE on all roadways (regardless of speed limit) Read the entire page →
From page 48... ... • Pavement conditions (e.g., dry or wet) for fatal and total curb crashes were very similar to those for all SV fatal and total crashes: 90.3% of the curb-related fatal crashes occurred on dry pavement, 7.9% on wet pavement, and 1.2% in snow/slush/ice; 74.7% of the curb-related total crashes occurred on dry pavement and 21.8% on wet pavement. Read the entire page →
From page 49... ... for each state. Since assigned operating speed for the roadway where the crash occurred is a combination of land use and roadway class, distributions of rollover percentages were generated for four operating speed categories within each state. Read the entire page →
From page 50... ... TABLE 14 Frequency of overturning vehicles in SV curb crashes categorized by roadway operating speed (Michigan and Illinois data, 1996–97) Michigan IllinoisAssigned operating speed Did not overturn Overturned Percentage overturns Did not overturn Overturned Percentage overturns NA 50 4 7% 46 1 2% 40-49 mph 193 6 3% 59 6 9% 50-59 mph 633 28 4% 172 13 7% 60-69 mph 597 40 6% 75 8 10% 70-79 mph 30 5 14% 9 2 18% Total 1503 83 5% 361 30 8% Read the entire page →
From page 51... ... The crash rates developed for total SV crashes, injuryproducing SV crashes, and SV rollover crashes are shown in Table 2 in Appendix E for all three roadway classes. However, due to the small number of such crashes, only the rates related to urban freeways appeared to be somewhat meaningful; these are shown in Table 15. Read the entire page →
From page 52... ... Note that first meaningful included curb impacts as a second, third, or fourth event if all of the preceding events were nonobject/nonrollover events such as "loss of control" or "run off road." The noncurb crashes occurred on segments of roadway with a curb present on at least one side of the roadway (i.e., opposite shoulder or median) according to the roadway inventory data, but not where the crash occurred, based on the absence of curb in the sequence of events. Read the entire page →
From page 53... ... A subsequent model used assigned roadway operating speed instead of these two variables, since assigned operating speed was a direct function of speed limit within functional class. Both of these models contained rollover as a predictor and thus allowed controlling for rollover in examining curb versus noncurb severity. Read the entire page →
From page 54... ... , percentages within speed categories are presented for the total unweighted data, the total unweighted subset of cases with higher confidence, the weighted full sample and the weighted high-confidence subset. The weights in the latter two cases are those provided in the CDS data for each NASS-CDS case. Read the entire page →
From page 55... ... for the severe impacts or PDO for the nonsevere impacts. Roadway class and speed limit Fatal & severe injury crashes PDO crashes Interstate Highway (All Posted Speeds) Read the entire page →
From page 56... ... The major findings concerning extent of the problem, curb-crash characteristics, and leads to simulation and crash testing efforts include the following: • Curb-related crashes on roadways with speed limits of 40 mph (65 km/h) and above represented a very small percentage of either total fatal crashes (1%) Read the entire page →
From page 57... ... There was little difference between the curb and noncurb groups with respect to violations cited or whether the crash was considered "speed related." As might be expected from other research on alcohol use and crash severity, the data from Michigan did appear to hint at more alcohol use in the severe curb crashes than in the less severe crashes. • Severe curb impacts involved passenger cars and motorcycles more often than SUVs or pickups. Read the entire page →
From page 58... ... Data collected from the simulations included bumper trajectories and vehicle paths; acceleration-time histories; yaw, pitch and roll-time histories; yaw, pitch, and roll angle ratehistories; sequential snapshots; and TRAP results (i.e., occupant risk values) Read the entire page →
From page 59... ... For a given impact speed and angle, the mode of vehicle trajectory was similar for all curb types (for a given impact speed and angle, the maximum bumper trajectory occurs at approximately the same point, regardless of curb type) Read the entire page →
From page 60... ... The roll angle 60 increased as curb height increased and decreased as impact angle increased. • Roll rates were also independent of the slope of the curb face, and they were minimally affected by impact speed. Read the entire page →
From page 61... ... The results indicate that ASI values were proportional to impact speed, impact angle, curb height, and the slope of the curb face. This suggests that a driver was much less likely to lose control while traversing a lower curb with a more mild, sloping face (e.g., the New York curb) Read the entire page →
From page 62... ... While the front wheels started to rebound, the vehicle began to roll, extending the back right suspension and compressing the left suspension. The front left suspension then started to compress again, while the right one maintained a steady elongation because it encountered the descending slope of the backfill while the cabin rolled back. Read the entire page →
From page 63... ... Maximum roll, pitch, and yaw angle displacements of C2500 pickup truck by curb type and speed at impact. Read the entire page →
From page 64... ... : Front right wheel Front left wheel Back right wheel Back left wheel 73 103 62 50 67 103 65 59 55 115 75 60 111 106 82 74 Maximum extension (mm) : Front right wheel Front left wheel Back right wheel Back left wheel 57 75 85 46 54 64 82 65 47 58 81 51 54 69 115 103 Maximum vertical acceleration (g) Read the entire page →
From page 65... ... Impact angle 15° 25° Maximum compression (mm) : Front right wheel Front left wheel Back right wheel Back left wheel 137 136 93 133 100 113 91 103 Maximum extension (mm) Read the entire page →
From page 66... ... Since offset curb–barrier combinations are more common along low- to Impact angle 15° 25° Maximum compression (mm) : Front right wheel Front left wheel Back right wheel Back left wheel 126 96 81 96 67 112 79 99 Maximum extension (mm) Read the entire page →
From page 67... ... Based on the bumper trajectory plots obtained from the curb traversal study, a vehicle impact speed of 70 km/h and angle of 25 degrees will result in the height of the front bumper continuously increasing from the time of wheel contact with the curb to a lateral offset distance of approximately 4 m behind the curb. The bumper will be higher than the top of the guardrail until the vehicle reaches a lateral distance of 5 m behind the curb. Read the entire page →
From page 68... ... • In cases involving the barrier positioned at 2.5-m offset from curb types B, C, D, and G, the sequential views of the impact events suggested that the vehicle would experience moderate roll angle during impact and a relatively high yaw rate, the front of vehicle redirecting out of the system before the rear of the vehicle contacted the rail. Also, while for cases involving 150-mm curb types the bumper of the vehicle climbed above the rail, there was little possibility of override in these cases. Read the entire page →
From page 69... ... Excessive roll angle, bumper above rail 100 km/h G Likely - Likely Bumper over rail, truck rollover B - - - Analysis terminated during redirection C - - - Stable redirection D - - - Stable redirection G - - - 70 km/h NY Analysis Not Conducted B - - - Stable redirection, high yaw rate 85 km/h C - - - Stable redirection, high yaw rate B Likely - - Override C Likely - - Override D Analysis Not Conducted G Likely - - Override Possible - - 4.0 m 100 km/h NY Analysis terminated prematurely during redirection Excessive trajectory Read the entire page →
From page 70... ... In those cases the position of the front bumper on the impact side was relatively lower and, according to the sequential views, the bumper stayed below the top of the rail throughout the impact event. For the scenarios involving impact speeds of 100 km/h, the initial roll angle was typically either zero or positive, while the initial pitch angle was typically negative. Read the entire page →
From page 71... ... In all cases, however, there appeared to be potential for excessive anchor movement and rail rupture during impact. The maximum rail forces under Test 3-11 conditions for curb–barrier offset distances greater than 0.0 m are not shown in the table because the predominate outcome in all those cases was barrier override. Read the entire page →
From page 72... ... Maximum tensile force in W-beam rail Impact region Upstream anchor Downstream location Offset distance Impact speed Curb type (kN) Force/ 209 (kN) Read the entire page →
From page 73... ... The results of the FEAs regarding higher-speed impact indicated that the roll angle and pitch angle of the vehicle after traversing curbs had a significant influence on the kinematics of the vehicle during impact with the guardrail for cases involving offset distances of 2.5 m and 4.0 m. The potential for override was increased when the roll angle of the vehicle was positive (i.e., roll away from the barrier) Read the entire page →
From page 74... ... ORA - high lateral ORA B ✓ - high pitch angle - high rail forces N/A ✗ - override -excess long. ORA - high lateral ORA - high roll angle C ✗ - override - rollover -excess lateral ORA - high trans. Read the entire page →
From page 75... ... Maximum dynamic deformation of the guardrail was 0.4 m, and the permanent deformation was 0.3 m. The right front wheel forced posts 15 and 16 to deform in the initial impact, E-TECH test no. Read the entire page →
From page 76... ... Maximum Roll Angle .............................................. 6.5 Maximum Pitch Angle ............................................ Read the entire page →
From page 77... ... Maximum Roll Angle .............................................. 472.1 Maximum Pitch Angle ............................................ Read the entire page →
From page 78... ... Maximum Roll Angle .............................................. -41.9 Maximum Pitch Angle ............................................ Read the entire page →
From page 79... ... The pickup sustained minor dents in the bumper and right front fender, a major dent in the bed on the driver's side, and major damage to the front right wheel and suspension; the frame was bent. There was no windshield contact or damage, and negligible deformation of the vehicle interior. Read the entire page →
From page 80... ... Maximum Roll Angle .............................................. 31.9 Maximum Pitch Angle ............................................ Read the entire page →
From page 81... ... Maximum Roll Angle .............................................. -8.9 Maximum Pitch Angle ............................................ Read the entire page →
From page 82... ... Maximum Roll Angle .............................................. 6.9 Maximum Pitch Angle ............................................ Read the entire page →
From page 83... ... Maximum Roll Angle .............................................. 17.0 Maximum Pitch Angle ............................................ Read the entire page →
From page 84... ... Nominal speed (km/h) Curb type Curb offset (m) Read the entire page →

From page 46...

... Table 10 presents FARS data for the 1994–99 period concerning how often "Curb" was noted as the FHE in fatal crashes on roads with speed limits of 40 mph (65 km/h) or greater for all crashes and SV fatal crashes.