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62 Impact Speed of 70 km/h Impact Speed of 100 km/h 0.28 0.32 0.28 0.24 0.24 0.20 0.20 0.16 0.16 0.12 0.12 0.08 0.08 0.04 0.04 0 5 10 15 20 25 30 0 5 10 15 20 25 30 Impact Angle (degrees) Impact Angle (degrees) A Curb B Curb D Curb C Curb G Curb NY Curb Figure 33. ASI of C2500 pickup truck by impact angle and each curb type at impact speeds of 70 km/h and 100 km/h, based on FEA. Live-Driver Curb Traversal Tests A number of tracking tests were first performed at 35 mph with the B, C, D, and NY curbs. The driver was able to achieve As described in Chapter 4, low-speed curb-traversal tests reasonably repeatable impact conditions and did not report any were conducted using a live driver and a C2500 pickup truck. uncontrollable behavior of the vehicle, although at times he These tests were primarily used to validate the finite-element reported feeling strong shocks to the steering wheel. The vehi- model of the roadway and curb. cle traversed all the curbs without impacting any components Tests were performed on the Type B curb, Type G curb, other than the tires. Minor damage occurred to the tread of the and 6-in. vertical curb at impact angles of 10, 15, 25, and tire impacting the curb, including plugs torn from the tire. 90 degrees. Tables 21 through 23 summarize the results. Tables 24 to 27 summarize the results of these tests. The sequence of events that occurred in these tests is illus- Nontracking tests were then conducted at 35 mph on the trated in Figure 35, which is a series of snapshots of the same curbs. Two nontracking scenarios were used: (1) over- 25-degree test with the B curb. The vehicle impacted the curb steering and (2) understeering. During these tests, extreme at approximately 25 km/h, striking it first with the right front trajectories and roll angles were often recorded in the impacts, wheel. The front right suspension was compressed by the and the anti-rollover outrigger was engaged twice, prevent- impact, and the linkage provided by the stabilizer bar caused ing the physical rollover of the vehicle. The vehicle was not the left suspension to slightly compress as well. While the damaged during the testing of the NY and C curbs; but, dur- front wheels started to rebound, the vehicle began to roll, ing the testing of the B and D curbs, damage to the wheels extending the back right suspension and compressing the left and the steering system was reported. In particular, bending suspension. The front left suspension then started to com- of the rims was noticed each time they came into direct con- press again, while the right one maintained a steady elonga- tact with the concrete curbs. Tire blow-out (i.e., tire failure tion because it encountered the descending slope of the back- by debedding and subsequent sudden air loss) was recorded fill while the cabin rolled back. When the right back wheel in four cases. After one test with the D curb, the neutral posi- impacted the curb, the right back suspension experienced a tion of the steering wheel was 180 degrees off-center, appar- sudden compression. The impact force and rolling moment ently a result of damage to one or more parts of the steering were transferred to the chassis, thus extending the two rear system. The B and D curbs also suffered severe damage, suspensions. During this phase, the relative rolling of the bed including gouges, scrapes, and broken concrete from the with respect to the pickup truck cabin was apparent. The lat- impact of the rims and rim flanges. eral force caused by the impact of the back right wheel Tables 28 through 31 summarize the results of the non- against the curb caused the vehicle to yaw towards the back- tracking tests. fill behind the curb. In one of the tests, the high-speed video showed that the left back wheel left the ground right after the rebound. The pitching moment due to the back right wheel impact compressed the front suspension. CURBGUARDRAIL SIMULATIONS AND TESTS As described in Chapter 4, live-driver curb traversal tests were also conducted at moderate speeds, with the vehicle Finite-element simulations and full-scale crash tests were approaching the curb in both tracking and nontracking modes. also used to investigate the response of a 3/4-ton pickup truck

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63 70 km/h 100 km/h 8 8 Max Roll Angle (degrees) Max Roll Angle (degrees) 7 7 6 6 5 5 4 4 3 3 2 2 1 1 0 0 0 5 10 15 20 25 30 0 5 10 15 20 25 30 Impact Angle (degrees) Impact Angle (degrees) 70 km/h 100 km/h 3.50 Max Pitch Angle (degrees) 3 Max Pitch Angle (degrees) 3 2.50 2 2 1.50 1 1 0.50 0 0 0 5 10 15 20 25 30 0 5 10 15 20 25 30 Impact Angle (degrees) Impact Angle (degrees) 70 km/h 100 km/h 30 30 Max Yaw Angle (degrees) Max Yaw Angle (degrees) 20 20 10 10 0 0 -10 -10 -20 -20 0 5 10 15 20 25 30 0 5 10 15 20 25 30 Impact Angle (degrees) Impact Angle (degrees) A Curb B Curb D Curb C Curb G Curb NY Curb Figure 34. Maximum roll, pitch, and yaw angle displacements of C2500 pickup truck by curb type and speed at impact.

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64 TABLE 21 Type B curb low-speed, live-driver test summary Impact angle 10 15 25 90 Maximum compression (mm): Front right wheel 73 86 102 110 Front left wheel 58 59 54 115 Back right wheel 39 50 38 97 Back left wheel 48 43 76 93 Maximum extension (mm): Front right wheel 59 39 32 95 Front left wheel 43 30 52 69 Back right wheel 81 84 85 118 Back left wheel 50 61 46 99 Maximum vertical acceleration (g): C.G. of truck 0.9 1.0 1.1 2.0 Bed of truck 2.5 2.5 3.7 6.2 TABLE 22 Type G curb low-speed, live-driver test summary Impact angle 10 15 25 90 Maximum compression (mm): Front right wheel 73 67 55 111 Front left wheel 103 103 115 106 Back right wheel 62 65 75 82 Back left wheel 50 59 60 74 Maximum extension (mm): Front right wheel 57 54 47 54 Front left wheel 75 64 58 69 Back right wheel 85 82 81 115 Back left wheel 46 65 51 103 Maximum vertical acceleration (g): C.G. of truck 1.2 1.4 1.8 1.3 Bed of truck 3.5 3.9 3.9 4.6 TABLE 23 Vertical 6-inch curb low-speed, live-driver test summary Impact angle 10 15 25 90 Maximum compression (mm): Front right wheel 102 119 132 131 Front left wheel 53 85 87 128 Back right wheel 88 90 115 104 Back left wheel 60 57 88 113 Maximum extension (mm): Front right wheel 89 75 64 90 Front left wheel 62 70 41 87 Back right wheel 48 85 125 189 Back left wheel 175 244 256 114 Maximum vertical acceleration (g): C.G. of truck 1.1 1.6 2.0 2.5 Bed of truck 3.8 5.4 7.4 6.8 impacting curbbarrier systems in which the barrier was a 70 km/h and 25 degrees (i.e., NCHRP Report 350 modified G4(1S) guardrail with wood blockouts. Test 2-11). The study included the modified G4(1S) guardrail installed CurbGuardrail Simulations in combination with five curb types: AASHTO Types B, C, D, and G, and the 100-mm New York curb. LS-DYNA was used to analyze various curbguardrail systems subjected to impact by the modified C2500 pickup truck model under three different impact conditions: Parametric Study 100 km/h and 25 degrees (i.e., NCHRP Report 350 A parametric study was again performed, this time vary- Test 3-11), ing the impact speed, curb type, and offset from the guardrail. 85 km/h and 25 degrees, and The impact angle was 25 degrees in all simulations.

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65 TABLE 24 Type B curb moderate-speed, live-driver test summary Impact angle 15 25 Maximum compression (mm): Front right wheel 137 100 Front left wheel 136 113 Back right wheel 93 91 Back left wheel 133 103 Maximum extension (mm): Front right wheel 111 93 Front left wheel 99 120 Back right wheel 75 64 Back left wheel 96 98 Maximum acceleration at C.G. (g): x +1.7 1.3 y -1.5 -1.4 z +4.0 +2.8 Stability Good Adequate TABLE 25 Type C curb moderate-speed, live-driver test summary Impact angle 15 25 Maximum compression (mm): Front right wheel 80 85 Front left wheel 123 57 Back right wheel 58 54 Back left wheel 65 113 Maximum extension (mm): Front right wheel 108 49 Front left wheel 82 105 Back right wheel 53 73 Back left wheel 52 94 Maximum acceleration at C.G. (g): x -1.4 +1.3 y +0.9 -1.2 z -2.0 +2.9 Stability Excellent Excellent TABLE 26 Type D curb moderate-speed, live-driver test summary Impact angle 15 25 Maximum compression (mm): Front right wheel 130 109 Front left wheel 101 111 Back right wheel 92 95 Back left wheel 105 136 Maximum extension (mm): Front right wheel 95 91 Front left wheel 131 141 Back right wheel 79 83 Back left wheel 104 102 Maximum acceleration at C.G. (g): x -1.5 +1.8 y +2.8 +1.9 z +2.1 +4.3 Figure 35. Sequential views of low-speed Type B curb Stability Excellent Adequate impact at 25 degrees.

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66 TABLE 27 NY curb moderate-speed, live-driver TABLE 30 Type D curb moderate-speed, nontracking test summary test summary Impact angle Average values for all tests Over- Under- 15 25 steering steering Maximum compression (mm): Maximum compression (mm): Front right wheel 126 67 Front right wheel 63 195 Front left wheel 96 112 Front left wheel 10 77 Back right wheel 81 79 Back right wheel 54 91 Back left wheel 96 99 Back left wheel 58 87 Maximum extension (mm): Maximum extension (mm): Front right wheel 101 81 Front right wheel 71 123 Front left wheel 126 89 Front left wheel 93 86 Back right wheel 93 57 Back right wheel 40 52 Back left wheel 64 104 Back left wheel 56 99 Maximum acceleration at C.G. (g): Maximum acceleration at C.G. (g): x +1.7 +1.3 x +3.5 +3.1 y +1.6 +1.2 y +3.5 +2.3 z +2.0 -1.9 z +1.7 +1.4 Stability Excellent Excellent Stability Poor Good TABLE 28 Type B curb moderate-speed, nontracking test summary TABLE 31 NY curb moderate-speed, nontracking test summary Average values for all tests Over- Under- steering steering Average values for all tests Over- Under- Maximum compression (mm): steering steering Front right wheel 131 76 Maximum compression (mm): Front left wheel 47 98 Front right wheel 90 47 Back right wheel 68 98 Front left wheel 84 77 Back left wheel 67 23 Back right wheel 70 74 Maximum extension (mm): Back left wheel 57 131 Front right wheel 87 110 Maximum extension (mm): Front left wheel 73 101 Front right wheel 51 83 Back right wheel 70 30 Front left wheel 105 83 Back left wheel 86 11 Back right wheel 68 60 Maximum acceleration at C.G. (g): Back left wheel 78 61 x +2.7 +1.8 Maximum acceleration at C.G. (g): y +5.5 +4.0 x +1.5 +1.5 z 4.0 +3.7 y +2.2 +1.9 Stability Adequate Adequate z +1.3 +2.5 to Poor Stability Good Excellent TABLE 29 Type C curb moderate-speed, nontracking test summary The AASHTO curbs used in this study were the types most Average values for all tests Over- Under- commonly used. Although according to the survey discussed steering steering in Chapter 3 many states did not use AASHTO curbs, most Maximum compression (mm): of them used curbs that were at least similar to one of these Front right wheel 108 54 Front left wheel 102 100 four types (i.e., B, C, D, and G) or Type A. The Type A curb Back right wheel 77 74 was excluded from the curbguardrail study because the Back left wheel 62 141 results of the curb traversal study involving this curb were Maximum extension (mm): Front right wheel 82 97 inconclusive. Front left wheel 92 92 Three curb placement scenarios were investigated. One Back right wheel 82 46 scenario involved each of the curbs placed behind the face of Back left wheel 87 75 the barrier with the front of the curb flush with the front of the Maximum acceleration at C.G. (g): x +3.4 +1.6 W-beam where possible. This scenario was consistent with y +2.2 +2.0 the recommendations of the FHWA memorandum of Feb 28, z +2.5 +2.0 1992, and was expected to provide useful information to the Stability Poor Good states about the performance of these currently advocated curbbarrier combinations (27). Two other curb-placement scenarios were investigated to determine the effects of curbs placed in combination with guardrails where the offset dis- tance from curb to barrier is greater than zero. Since offset curbbarrier combinations are more common along low- to

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67 moderate-speed roadways (i.e., less than 80 km/h), analyses curb. The bumper remained higher than the guardrail for a of such combinations were primarily conducted for NCHRP lateral distance of approximately 8 m in this case, with the Test Level 2 conditions (i.e., 70 km/h), although a select maximum height occurring between 4 and 6 m. Computer- number of impacts with certain combinations were investi- simulated impacts with curbbarrier systems at an offset dis- gated at higher speeds. The placement of the curbs in those tance of 4 m were investigated under impact conditions con- analyses was based on the results of the curb traversal study sistent with NCHRP Report 350 Test 3-11. The performance of discussed previously, with consideration given to the clear certain curbbarrier systems was also investigated at 85 km/h, zone distances that were required for typical roadways. which represented the upper speed range for intermediate- The backfill and the roadway terrain in the computer model speed roadways (i.e., 60 to 80 km/h). simulations had zero slope. For design speeds of 70 to 80 km/h, Table 32 is a matrix of the simulations performed. the Roadside Design Guide states that the clear zone distance The backfill area behind the curbs was modeled with rigid should range from 3.5 m for roadways with an average daily elements using a dynamic coefficient of friction of 0.82 traffic (ADT) volume of less than 750 vehicles to 6.5 m for between the tires of the vehicle and the ground surface. It roadways with an ADT of greater than 6,000 vehicles (2). should be noted that the interaction between the tires and For design speeds of 100 km/h the clear zone distance ranges ground in these analyses may not accurately represent cases from 5 to 8.5 m, depending on ADT. Based on the bumper where the backfill is composed primarily of soft soil. trajectory plots obtained from the curb traversal study, a Data collected from the simulations included sequential vehicle impact speed of 70 km/h and angle of 25 degrees will snapshots of the impact event; acceleration-time histories; result in the height of the front bumper continuously increas- yaw, pitch, and roll time histories; W-beam tensile force- ing from the time of wheel contact with the curb to a lateral time histories; and TRAP results (i.e., occupant risk). Much offset distance of approximately 4 m behind the curb. The more detail on the analyses and results can be found in bumper will be higher than the top of the guardrail until the Plaxico's dissertation (52). vehicle reaches a lateral distance of 5 m behind the curb. Since the middle value of the clear zone distance is approxi- mately 5 m, offset distances of 5 m or greater were not inves- Results tigated since the guardrail would not have been warranted outside the clear zone area. In those cases, offset distances of At the beginning of each simulation, the vehicle was aligned 2.5 and 4.5 m were investigated under impact conditions con- to impact post 14 of the guardrail system. This point is 2.4 m sistent with NCHRP Report 350 Test 2-11. upstream of a splice connection. The exact impact point can For the case of the pickup traversing a curb at 100 km/h vary when a barrier is offset from a curb, depending on the and 25 degrees, the bumper trajectory plots from the curb tra- yaw angle of the vehicle after impact with the curb. versal study indicated that the bumper height continuously It is important to note that vehicle impact into roadside increased after wheel impact with the curb until the vehicle barriers is highly nonlinear, which means that small varia- reached a lateral distance of approximately 6 m behind the tions in the system may lead to very different results. Such TABLE 32 Simulations of impact tests with a curb and G4(1S) guardrail system Offset distance from barrier to curb Curb type 0m 2.5 m 4m Simulation Test B 2-11: Impact speed 70 C km/h, D Angle of 25 degrees G NY Simulation Test B 3-11: Impact speed 100 C km/h, D Angle of 25 degrees G NY Simulation: B Impact speed 85 C km/h, Angle of 25 degrees

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68 variations may include impact conditions, impact location on Vehicle Kinematics. Sequential snapshots of the impact the barrier, vehicle suspension properties, soil conditions, event provided a qualitative means of evaluating the general barrier connections, and barrier component properties, to behavior of vehicle interaction with the guardrail as well as name only a few. Because of the nature of these factors, the the important safety issues regarding vehicle kinematics, results of the FEAs should only be viewed as a tool for assess- such as barrier override, barrier underride, vehicle overturn, ing the performance of the system; they only represent a pos- and vehicle redirection. Table 33 summarizes the results of sible outcome for the conditions specified. For example, in these evaluations. The conclusions reached are given in the many cases the trajectory of the vehicle during interaction with following paragraphs. the barrier causes the tires to impact higher than normal against For impacts at 70 km/h and 25 degrees, all five curb types the W-beam rail. With the wheels in this position, the connec- were analyzed. The following results were notable: tion of the W-beam to the post becomes a critical factor. If the connection between the W-beam and post does not fail quickly In cases involving the barrier positioned at 0-m offset enough during impact, the posts may pull the W-beam down from the curb, it appeared that the vehicle remained to a point that allows the wheels of the vehicle to ride up the very stable throughout the impact event and barrier damage appeared to be minimal, regardless of curb type. rail and launch the vehicle, as was the case involving the sim- Although the scenario with the 150-mm AASHTO type ulation of the modified C2500R impacting an AASHTO C D curb resulted in the bumper getting above the rail dur- curb at 100 km/h and 25 degrees with the guardrail posi- ing redirection, the potential for override of the barrier tioned at 0-m offset from the curb, as shown in Figure 36. appeared minimal. A similar event also occurred in a recent crash test per- In cases involving the barrier positioned at 2.5-m offset formed at the Midwest Roadside Safety Facility in Lincoln, from curb types B, C, D, and G, the sequential views of Nebraska, which was documented in a test report by Polivka the impact events suggested that the vehicle would et al. (29). That test involved a modified G4(1S) guardrail experience moderate roll angle during impact and a rel- with a 102-mm curb placed underneath the rail behind the atively high yaw rate, the front of vehicle redirecting out face of the W-beam under impact conditions corresponding of the system before the rear of the vehicle contacted the to NCHRP Report 350 Test 3-11. A section of the guardrail rail. Also, while for cases involving 150-mm curb types in the impact region incorporated two layers of W-beam (i.e., the bumper of the vehicle climbed above the rail, there nested W-beams) to reduce the potential for rupture. Conse- was little possibility of override in these cases. The quently, this resulted in four layers of W-beam at the splice impact scenario involving the 100-mm New York curb connections, which required a much higher force to pull the resulted in very stable redirection, although the yaw rate head of the bolt through W-beam slots in the connection of appeared somewhat high in this case as well. the rail to the posts. As a result of the stronger connection, In cases involving the barrier positioned at 4.0-m offset the W-beam rail was pulled down and the vehicle launched from the curbs, the vehicle remained very stable through- into the air. Although the vehicle experienced extreme tra- out the impact event and barrier damage appeared to be jectory during the impact, the vehicle remained upright and minimal, regardless of the type of curb used in conjunc- came down on the front side of the guardrail and satisfied all tion with the guardrail. However, the vehicle appeared requirements of NCHRP Report 350. The repeatability of to experience a high yaw rate during redirection, which such an event is questionable due to the instability of the could increase risk of occupant injury. vehicle during impact with the system; slight changes in For impacts at 85 km/h and 25 degrees, only two curb types, either the system or impact conditions may lead to drastically the type B and C curbs, were used in these curbbarrier sce- different results. narios. These cases were analyzed in order to assess the per- formance of the curbbarrier systems at speeds correspond- ing to the upper bound of the moderate-speed range (i.e., 60 to 80 km/h) and the lower bound of the high-speed range (i.e., >80 km/h). The following results were observed: In the cases involving the barrier positioned at 0.0-m off- set from the curbs, the sequential views of the impact sug- gested that the vehicle would remain relatively stable dur- ing impact. There was a slight pitch of the vehicle when the rear wheels contacted the 150-mm Type B curb. In the cases with the barrier positioned at 2.5-m offset from the curb, the analyses terminated prematurely due Figure 36. FEA simulation of C2500 pickup impacting to numerical problems in the calculations that were guardrail with C curb under rail. related to contact between the W-beam rail and truck

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TABLE 33 Curbguardrail FEA for vehicle override, underride, rollover, and redirection Offset Impact Curb Over- Under- Roll- Redirection distance speed type ride ride over comments 0.0 m 70 km/h B - - - Stable redirection C - - - Stable redirection Slight bumper trajectory, D - - - stable redirection G Analysis Not Conducted NY - - - Stable redirection 85 km/h B - - - Slight pitch C - - - Stable redirection 100 km/h B - - Possible Excessive pitch C Likely - Likely Excessive trajectory D - - Possible Excessive pitch G - - Possible Excessive pitch Moderate pitch, NY - - - stable redirection 2.5 m 70 km/h Moderate roll angle, high yaw rate, B - - - bumper above rail - - - Moderate roll angle, high yaw rate, C slight bumper trajectory Moderate roll angle, high yaw rate, D - - - bumper above rail, tie rod breaks Moderate roll angle, high yaw rate, G - - - bumper above rail - - - Stable redirection, NY high yaw rate 85 km/h Likely - - Analysis terminated Excessive roll angle, bumper above B prematurely as bumper rail started over rail. Likely - - Analysis terminated Excessive roll angle, bumper above C rail prematurely as bumper started over rail. 100 km/h G Likely - Likely Bumper over rail, truck rollover 4.0 m 70 km/h Analysis terminated B - - - during redirection C - - - Stable redirection D - - - Stable redirection G - - - NY Analysis Not Conducted 85 km/h Stable redirection, B - - - high yaw rate Stable redirection, C - - - high yaw rate 100 km/h B Likely - - Override C Likely - - Override D Analysis Not Conducted G Likely - - Override Possible - - NY Analysis terminated Excessive trajectory prematurely during redirection

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70 fender. The analyses did continue long enough, how- the time the analysis was stopped the trajectory and roll ever, to conclude that there was a potential for excessive angle of the truck was excessive enough to suspect bar- roll of the vehicle during impact and that the bumper rier override, the likelihood of rollover, or both. was likely to get over the W-beam rail. Furthermore, the momentum of the truck combined with the excessive Vehicle Angular Displacement. The roll, pitch, and yaw trajectory of the bumper was sufficient to cause barrier angle displacement-time history data were collected at the override. center of gravity of the vehicle during the impact event. In the cases involving the barrier positioned at 4.0-m Table 34 summarizes the vehicle's angular position at the offset from the curb, the sequential views of the impact time of impact with the guardrail, the maximum roll and pitch events suggested that the vehicle would remain stable angle of the vehicle during the impact event, and the yaw but was likely to experience a high yaw rate during angle of the vehicle as it exited the guardrail. The following redirection. observations are based on these data: For impacts at 100 km/h and 25 degrees, all five curb types When the barrier was offset 2.5 m from the curb and the were analyzed with the barrier offset 0.0 m and 4.0 m from truck impacted the system at 70 or 85 km/h, the initial the curb. Only the Type G curb was analyzed for a barrier off- roll and pitch angle of the vehicle at the time of impact set 2.5 m from the curb. The following results were observed: with the guardrail were typically both positive (i.e., away from the guardrail) with the exception of the NY The sequential views of the simulated impact events curb. This resulted in the front bumper on the impact involving the barrier positioned at 0.0-m offset from the side of the vehicle being higher than normal at the time curbs indicated that rollover of the vehicle was possible of impact and, according to a qualitative analysis of the for each curbbarrier scenario involving the types B, C, sequential views of the impact, the bumper was above D, and G curbs due to excessive pitch of the vehicle dur- the rail during impact for each of these cases. The max- ing redirection. Although the vehicle did not roll over imum roll angle of the vehicle during impact was rela- in the simulations, the amount of damage to the front tively higher in those cases as well. impact-side wheel during impact and the position of the In the cases involving the barrier offset a distance of front wheels during redirection became a critical factor 4.0 m from the curb and impact speeds of 70 and 85 km/h, regarding vehicle stability when the pitch angle of the the opposite was typically true, with both the initial roll vehicle was excessive during redirection. In the simula- and pitch angle of the vehicle being negative at the time tions, the wheels remained undamaged and in straight of impact with the guardrail. In those cases the position alignment during redirection. There was one case of bar- of the front bumper on the impact side was relatively rier override involving the Type C curb. In this analysis, lower and, according to the sequential views, the bumper a wheel snag against a guardrail blockout early in the stayed below the top of the rail throughout the impact impact event caused the tie rod to break. The front event. For the scenarios involving impact speeds of wheel on the impact side of the vehicle then rotated 100 km/h, the initial roll angle was typically either zero 90 degrees toward the guardrail. The W-beam rail was or positive, while the initial pitch angle was typically pushed down and the vehicle launched over the guardrail. The impact scenario involving the 100-mm New York negative. In those cases the trajectory and momentum of curb at a 0.0-m offset from the barrier resulted in mini- the vehicle dominated and the primary result was vehi- mal trajectory of the vehicle with only moderate pitch cle override. and a relatively stable redirection. In all cases involving the barrier offset at distances of In the case involving the barrier positioned at 2.5-m 2.5 m or 4.0 m from the curb, the curb caused the wheels offset from the Type G curb, the trajectory of the truck of the truck to steer toward the guardrail while the vehi- was excessive during impact and, although the trajec- cle traversed the curb, resulting in the vehicle impacting tory of the front bumper and the momentum of the vehi- the guardrail at a steeper than normal angle. Conse- cle appeared sufficient to cause the vehicle to override quently, for any given curbbarrier case, the impact angle the barrier, the guardrail redirected the vehicle away from became steeper as the offset distance increased. A steeper the system. The vehicle then proceeded to roll over onto impact angle may increase the severity of the impact by its side. increasing the potential for failure of the barrier and by In the cases involving the barrier positioned at 4.0-m increasing occupant risk factors. offset from the curb, the sequential views of the impact events suggested that barrier override was likely regard- Tensile Force in the Guardrail. The maximum values of less of curb type. Note: the analysis involving the 100-mm tensile force in the W-beam cross-section at two critical loca- New York curb resulted in premature termination due to tions (i.e., in the impact region of the guardrail and at the numerical problems in the calculations that were related upstream anchor) as computed in the FEAs are summarized to contact between the front tire and the W-beam, but at in Table 35. The cases involving the modified C2500R pickup

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71 TABLE 34 Angular displacement-time history data collected at the center of gravity of the vehicle in the curbguardrail FEAs Impact angle with Max. angular displacement in Offset Impact Curb guardrail (degrees) impact (degrees) distance speed type Roll Pitch Yaw Roll Pitch Yaw 0.0 m 70 B 0.0 0.0 -25.0 -1.9 -6.4 21.0 km/h C 0.0 0.0 -25.0 -7.0 -3.7 21.0 D 0.0 0.0 -25.0 2.2 3.5 20.2 G Analysis not conducted NY 0.0 0.0 -25.0 -4.3 -2.1 21.3 85 B 0.0 0.0 -25.0 5.4 -7.6 19.3 km/h C 0.0 0.0 -25.0 8.2 -3.3 18.5 100 B 0.0 0.0 -25.0 -18 -14.2 22.4 km/h C 0.0 0.0 -25.0 31.3 6.0 29.5 D 0.0 0.0 -25.0 -12.5 -14.3 24.2 G 0.0 0.0 -25.0 -11.4 -21.6 23.0 NY 0.0 0.0 -25.0 -10.9 -9.1 23.5 2.5 m 70 B 0.27 0.44 -25.8 -11.9 -3.2 13.7 km/h C Data not recorded due to input error D 0.89 1.13 -26.8 -11.4 -5.2 18.9 G 3.48 0.16 -26.2 -14.1 -6.3 19.9 NY 2.87 -0.17 -26.0 -8.4 -5.2 15.8 85 B 1.22 1.33 -25.7 - - - km/h C 2.92 0.55 -26.3 - - - 4.0 m 70 B -1.95 -1.14 -28.8 5.1 -2.8 NA km/h C -3.39 -2.48 -28.0 -7.6 -2.7 17.7 D -1.80 -1.55 -29.7 5.6 -2.9 19.2 G 0.49 -0.85 -26.8 4.4 -3.4 14.6 NY Analysis not conducted 85 B -1.63 -0.81 -27.8 -10.8 -2.0 18.9 km/h C -0.82 -1.78 -28.1 -6.3 -3.2 17.0 100 B 0.0 -0.49 -28.7 -19.6 -6.2 NA km/h C -0.06 -1.42 -27.6 -6.7 -3.5 NA G 2.21 -0.93 -27.5 -45.1 3.5 NA NY 1.84 -0.95 -27.5 -15.2 -3.1 NA model impacting the guardrail at 100 km/h and 25 degrees The results from the analyses of vehicle impact at 85 km/h with an offset distance of 0.0 m from curb to barrier are com- at 25 degrees indicated that rupture of the guardrail was pared to the results of the modified C2500R pickup model not likely to occur for offset distances of 0 m or 4 m. impacting the guardrail under the same impact conditions When the guardrail was placed 2.5 m behind the curb, without a curb present. In cases in which the rail forces were the tension in the rail reaches magnitudes that may be significantly higher when the curb was present than when it critical; however, there was also bumper override in was not, there may be a potential for rupture. For the simu- those cases. lation of the guardrail without a curb present under NCHRP The analyses of vehicle impact with the guardrail under Report 350 Test 3-11 conditions, the maximum force in the Test 3-11 conditions involving each of the different curb guardrail occurred in the impact region and was 209 kN and types located at 0-m offset (i.e., under the W-beam rail) the maximum anchor force was approximately 179 kN. The resulted in significantly higher forces in the rail and following conclusions were reached: anchor then when the curb was not present. In all cases, however, there appeared to be potential for excessive The results from the analyses of vehicle impact with the anchor movement and rail rupture during impact. The guardrail under Test 2-11 conditions involving each of maximum rail forces under Test 3-11 conditions for the different curb types indicated that rupture of the curbbarrier offset distances greater than 0.0 m are not guardrail was not likely to occur regardless of the offset shown in the table because the predominate outcome in location of the barrier with respect to the curb. all those cases was barrier override.

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72 TABLE 35 Maximum tensile force values in the W-beam rail within the impact region and at the upstream anchor, based on FEA Maximum tensile force in W-beam rail Impact Upstream Downstream Offset Impact Curb region anchor location distance speed type (kN) Force/ (kN) Force/ (kN) Force/ 209 179 147 0.0 m 70 B 127 0.61 - - 71.2 0.48 km/h C 127 0.61 124 0.69 87.8 0.60 D 128 0.61 127 0.71 82.9 0.56 G Analysis not conducted NY 135 0.65 131 0.73 76.0 0.52 85 B 165 0.79 141 0.79 117 0.80 km/h C 170 0.81 142 0.79 122 0.83 100 B 232 1.11 - - 182 1.24 km/h C 226 1.08 202 1.13 175 1.19 D 243 1.16 210 1.17 183 1.24 G 223 1.07 - - 174 1.18 NY 231 1.11 198 1.11 178 1.21 2.5 m 70 B 95.0 0.45 88.7 0.50 68.6 0.47 km/h C Data not recorded due to input error D 128 0.61 120 0.67 82.1 0.56 G 123 0.59 118 0.66 77.8 0.53 NY 132 0.63 119 0.66 77.7 0.53 85 B 185 0.89 - - 91.0 0.62 km/h C 205 0.98 177 0.99 102 0.69 4.0 m 70 B 101 0.48 89.4 0.50 66.1 0.45 km/h C 114 0.55 113 0.63 76.5 0.52 D 97.5 0.47 - - 65.1 0.44 G 130 0.62 116 0.65 78.8 0.54 NY Analysis not conducted 85 B 171 0.82 143 0.80 103 0.70 km/h C 171 0.82 148 0.83 120 0.82 For cases involving the guardrail positioned at 0.0-m off- of 0.0-m offset distance from curb to barrier at all three set from the curb, the maximum tension in the W-beam impact speeds. Seven of the cases for which the offset dis- rail ranged from 107% to 111% and the maximum force tance was greater than zero resulted in longitudinal ORA val- at the upstream anchor was as high as 117% of the val- ues exceeding 20 Gs: ues computed in the analysis of the guardrail without a curb present. 150-mm B curb, impact speed of 85 km/h and offset dis- tance of 4.0 m; TRAP Results. Table 36 summarizes the TRAP results, 150-mm B curb, impact speed of 100 km/h and offset including the OIV, occupant ridedown acceleration (ORA), distance of 4.0 m; and maximum 50-m/s moving average acceleration for each 100-mm C curb, impact speed of 85 km/h and offset dis- curbguardrail scenario. The OIV in all cases was below the maximum limit of 12 m/s, as required in NCHRP Report 350. tance of 2.5 m; For the curbbarrier scenarios in which the barrier was off- 100-mm C curb, impact speed of 100 km/h and offset set at 2.5 m or 4.0 m from the curb, the data analysis began distance of 4.0 m; at first tire contact with the curb. In some of these cases, 100-mm G curb, impact speed of 70 km/h and offset dis- occupant impact occurred prior to vehicle impact with the tance of 2.5 m; barrier (e.g., Type D curb, 70 km/h impact speed, 2.5-m off- 100-mm G curb, impact speed of 70 km/h and offset dis- set), which resulted in very low values of OIV. tance of 4.0 m; and The longitudinal ORA values were below the maximum 100-mm G curb, impact speed of 100 km/h and offset limit of 20 Gs required in NCHRP Report 350 for the cases distance of 4.0 m.

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73 TABLE 36 Occupant risk factors computed using TRAP and the results from the FEAs of the curbbarrier impact study OIV Max. 50-m/s moving Impact conditions ORA average Curb type Offset Speed x-dir y-dir x-dir y-dir x-dir y-dir z-dir distance (km/h) (m/s) (m/s) (Gs) (Gs) (Gs) (Gs) (Gs) (m) 0.0 4.1 -3.6 -6.0 4.7 -4.6 3.3 2.0 70 25 35 -2 5 -15 1 19 4 46 -10 0 74 40 20 -4 5 13 6 -19 2 -6 3 83 -6 7 00 42 -4 1 81 10 6 -4 2 57 42 B 150-mm curbs 85 25 - - - - - - - 40 01 -2 6 31 1 29 0 -14 7 10 1 -9 0 00 55 -5 0 -11 0 14 9 -5 4 76 33 100 40 36 03 -40 0 -49 9 -13 1 96 -14 6 00 43 -4 1 -6 6 67 -4 6 37 -2 0 70 25 -0 1 16 -12 7 17 3 -5 6 58 -7 7 D 40 03 -1 6 13 3 14 4 -3 9 72 51 100 0.0 5.9 -4.8 -14.0 15.9 -5.4 7.1 3.5 00 42 -4 2 -6 3 75 -4 0 38 -1 7 70 2.5 - - - - - - - 4.0 1.6 1.4 14.4 13.8 6.9 6.3 6.8 0.0 4.1 -4.3 -12.9 12.6 -4.1 5.5 2.3 C 85 2.5 6.1 -3.6 -25.2 -22.0 -9.2 8.5 -12.5 4.0 0.7 -1.7 -20.0 16.9 -6.9 5.8 6.7 100 0.0 5.7 -5.0 8.7 7.4 -5.3 6.0 -3.9 100-mm curbs 4.0 5.0 -3.8 -40.0 -49.9 -6.5 5.8 -4.2 70 0.0 - - - - - - - 2.5 6.0 -2.4 -26.6 17.2 -6.6 5.2 -8.2 G 4.0 1.1 -2.6 21.2 -16.8 -8.5 5.6 6.9 100 0.0 4.8 -5.3 -11.6 14.8 -5.0 7.0 2.5 4.0 6.3 -4.9 26.2 -29.2 13.4 -9.6 -11.5 0.0 4.7 -4.2 -5.1 5.7 -4.7 4.1 1.5 70 2.5 5.8 -4.5 -11.0 10.9 -4.4 6.4 -5.1 NY 4.0 - - - - - - - 0.0 5.0 -5.2 -8.2 13.1 -5.0 5.7 2.4 100 4.0 5.3 -5.6 -17.0 21.1 -10.4 9.3 6.7 Summary curb types. It was also concluded that vehicle stability may be an issue during redirection due to the high pitch angles of The results of the pickup truck model impacting the curb the vehicle when exiting the system. Furthermore, the tensile barrier combination at 0-m offset distance (i.e., curbs under forces in the W-beam were high during impact, indicating the face of the barrier) at speeds of 70 km/h and 85 km/h indi- potential for rail rupture at the splice connections, especially cate that the vehicle would remain stable throughout the for cases involving the 150-mm curbs. The most promising impact event and that barrier damage would be minimal combination involved the 100-mm New York curb, which regardless of the type of curb used. The bumper of the pickup resulted in safe redirection of the vehicle, although the ten- was above the rail during redirection in one case involving sile forces in the rail were somewhat high. the 150-mm AASHTO Type D curb, but the potential for The results of the FEAs regarding higher-speed impact indi- override of the barrier was considered minimal. cated that the roll angle and pitch angle of the vehicle after tra- At the higher impact speed of 100 km/h the analyses pro- versing curbs had a significant influence on the kinematics of vided mixed conclusions. In one case involving the 100-mm the vehicle during impact with the guardrail for cases involv- high Type C curb, the vehicle vaulted over the guardrail, ing offset distances of 2.5 m and 4.0 m. The potential for over- whereas vaulting was not a serious issue in the other cases. ride was increased when the roll angle of the vehicle was pos- The difference in this particular case was attributed to a itive (i.e., roll away from the barrier) at the time of impact with wheel snag against a blockout early in the impact event; this the guardrail. When the roll angle of the vehicle was negative affected the way the vehicle interacted with the barrier (i.e., roll toward the barrier) at the time of impact with the throughout the remainder of the event. Wheel snag is com- guardrail, rollover became a likely outcome. mon in impacts with strong-post W-beam guardrails, and At impact speeds of 70 km/h into curbguardrail systems similar results are possible for cases involving any of the at offset distances of 2.5 m and 4.0 m, there was very little

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74 probability of barrier override; but ORAs during redirection of impact speed, curb type, and offset distance because of were relatively high. In one case involving the 100-mm Type limited funds. G curb, the longitudinal ORAs exceeded the maximum value of 20 Gs allowed in NCHRP Report 350. At the intermediate speed of 85 km/h the results from the finite element simula- Full-Scale Crash Tests of CurbGuardrail tions indicated the potential for a pickup truck to override a Combinations standard strong-post W-beam guardrail located at 2.5-m off- set distance from both 150-mm and 100-mm curbs. At an off- As discussed in Chapter 4, full-scale crash tests were con- set distance of 4 m from curb to barrier, the guardrail redi- ducted of selected curbguardrail combination scenarios to rected the vehicle at an impact speed of 85 km/h. The ORAs complement the FEA results. A series of full-scale crash tests, of the vehicle during redirection were considered high, and each conforming to the recommendations in NCHRP Report the Type B curb resulted in excessive ORAs (i.e., greater 350 Test 11 for longitudinal barriers, was performed to vali- than 20 Gs). date the design chart described in Chapter 6. The barriers for Table 37 provides a summary of the results of the curb all tests were the AASHTO Standard G4(1S) or SGR04a barrier impact study regarding success or failure of the sys- guardrails, modified by the use of recycled plastic blockouts tem in each case, based on the information obtained from the instead of wood blockouts. The impacting vehicle for each analyses. Analyses were not conducted for all combinations test was a 2000P vehicle (i.e., 3/4-ton pickup truck). Testing TABLE 37 Summary of curbbarrier impact study regarding success () or failure () of the system based on the results of the FEAs Impact Curb Offset distance from barrier to curb speed type 0m 2.5 m 4m - high long. ORA B - high lateral ORA - high lateral ORA C ORA 70 km/h D - high lateral ORA -excess lateral ORA -excess lateral ORA G N/A - high lateral ORA - high lateral ORA NY N/A (assumed ) -excess lateral ORA B - override - high lateral ORA 85 km/h -excess lateral ORA - high long. ORA C - override - high lateral ORA - high lateral ORA - override - high pitch angle -excess long. ORA B - high rail forces N/A - high lateral ORA - high roll angle - override -excess lateral ORA - rollover - override C N/A (assumed ) -excess lateral ORA - high lateral ORA - high trans. ORA - high roll angle 100 - high pitch angle km/h D - high rail forces N/A N/A - rollover - override - high pitch angle - override -excess lateral ORA G - high rail forces -excess lateral ORA - high lateral ORA - high lateral ORA - high roll angle - high trajectory - high roll angle NY - high rail forces N/A - high long. ORA - high lateral ORA long. = longitudinal. N/A = not analyzed. trans. = [PI to supply]

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75 examined two types of curbs, three nominal impact speeds upstream of the connection splice at the 14th post in the and three curbbarrier offset distances. Inadvertently a fourth installation. The vehicle traversed the curb, forcing the tires variable was introduced in the test matrix, barrier height rel- to lose contact with the ground. The right corner of the ative to the curb approach. The test matrix was subsequently bumper came into contact with the top ridge of the W-beam expanded to compensate for this added variable. The test guardrail. The blockouts supported the W-beam and began matrix is shown in Table 38. loading the posts laterally. The front end of the vehicle rose up over the guardrail and the guardrail flattened and came to bear against the right front wheel. All four wheels became Test Results airborne, and, as the W-beam deflected laterally, it developed tension that forced the vehicle to yaw counterclockwise and Figures 37 through 43 summarize the full-scale crash tests. roll. The vehicle vaulted over the guardrail, rolled over, came Each figure shows the theoretical OIVs and ridedown accel- back down on the downstream section of guardrail, and then erations in the longitudinal and lateral directions, theoretical righted itself on all four wheels. Maximum dynamic defor- head impact velocity (THIV), post-impact head deceleration mation of the guardrail was 0.6 m, and the permanent defor- (PHD), ASI, and maximum roll, pitch, and yaw angles. mation was 0.4 m. The tire and rim forced posts 15 and 16 to Test 52-2556-001, conducted by E-TECH Testing Ser- deform in the initial impact, and the vehicle engaged two vices, Inc., is summarized in Figure 37. In this test, vehicle W-beam rails before losing contact. The vehicle subsequently contact with the test article occurred 2.5 m upstream of the damaged six downstream posts and one section of rail. The connection splice at the 15th post in the installation. The vehicle rolled to a stop 21 m downstream and approximately bumper was forced back crushing the front right fender and 6 m behind its position at impact. The furthest piece of debris, wheel well. The entire front right corner of the vehicle came a 6.4-kg blockout, ended up 0.5 m downstream and 1.5 m to to bear against the W-beam guardrail. The blockouts sup- the rear of its position at impact. The vehicle sustained major ported the W-beam and began loading the posts laterally. The dents in the bumper, right front fender, roof, hood, and pas- W-beam flattened out forming a ribbon that engaged the senger door, and the windshields, mirror, grill and right front vehicle. As the W-beam deflected laterally it developed ten- headlight were broken. There was a maximum 330 mm defor- sion that forced the vehicle to yaw counterclockwise. Maxi- mation of the vehicle interior at the right windshield pillar. mum dynamic deformation of the guardrail was 0.5 m, and E-TECH Test 52-2556-003 is summarized in Figure 39. In the permanent deformation was 0.4 m. The tire and rim this test, vehicle contact with the test article occurred 2.2 m forced posts 15 and 16 to deform. The vehicle engaged two upstream of the connection splice, just upstream of the 14th W-beam rails before losing contact with the installation. The post in the installation. The vehicle traversed the curb, forc- exit trajectory of the vehicle center of gravity was 14 degrees ing the tires to lose contact with the ground. The bottom of relative to the installation centerline when the vehicle lost con- the right corner of the bumper came into contact with the top tact with the barrier. The exit velocity of the vehicle was edge of the W-beam guardrail. The blockouts supported the 41.3 km/h. The emergency braking system was applied after W-beam and began loading the posts laterally. The front loss of contact and the vehicle skidded to a stop 34 m down- overhang of the vehicle rose up over the guardrail and the stream and 11 m left of its position at impact. The furthest piece guardrail came to bear against the right front wheel. All four of debris, a 6.4-kg blockout, ended up 4 m downstream and wheels became airborne, and the front end of the vehicle 7 m to the rear of its position at impact; the pickup sustained passed over the guardrail. The rear end of the vehicle slid major dents in the bumper, right front fender, and passenger along the top of the downstream section of guardrail, and door, and the grill and right front headlight were broken. There then the vehicle came to rest with the back tires on the guard- was no windshield contact or damage and negligible defor- rail and the front wheels on the ground behind the guardrail. mation of the vehicle interior. Maximum dynamic deformation of the guardrail was 0.4 m, E-TECH Test 52-2556-002 is summarized in Figure 38. In and the permanent deformation was 0.3 m. The right front this test, vehicle contact with the test article occurred 2.6 m wheel forced posts 15 and 16 to deform in the initial impact, TABLE 38 Full-scale crash test matrix Nominal E-TECH Curb Curb offset Guardrail height (mm) speed test no. type (m) relative to approach (km/h) 52-2556-001 85 B 0.0 550 52-2556-002 85 B 2.5 550 52-2556-003 80 NY 2.5 550 52-2556-004 80 NY 4.5 550 52-2556-005 80 NY 4.5 650 52-2556-006 70 NY 2.5 650 52-2556-007 85 NY 2.5 650

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76 t = 0.000 sec t = 0.144 sec t = 0.288 sec t = 0.432 sec t = 0.576 sec t = final SGR04a Guardrail Type B Curb General Information Test Agency ............................................................... E-TECH Testing Services, Inc. Test Designation ...................................................... NCHRP 350 Test 3-11 (modified) Exit conditions Test No. ..................................................................... 52-2556-001 Speed (km/h) ............................................................ 41.3 Date............................................................................ 6/5/03 Angle (deg - veh. c.g.) .............................................. 14 Test Article Occupant Risk Values Curb Type ................................................................. AASHTO Type B Impact Velocity (m/s) Barrier Length ....................................................... 53.34 m (overall) x-direction ........................................................ 4.9 Height (mm - relative to approach) ...................... 550 y-direction ........................................................ -4.7 Setback (m - relative to curb) ............................... 0 Ridedown Acceleration (g's) Material and key elements ...................................... AASHTO SGR04a Guardrail with x-direction ......................................................... -8.1 ............................................................................ SEW02a End Terminal equipped y-direction ......................................................... -6.3 ............................................................................ Re-Block recycled plastic blockouts European Committee for Normalization (CEN) Values ............................................................................ of 50% HDPE / 50% PP THIV (km/h) ............................................................. 24.1 PHD (g's) ................................................................... 8.8 Foundation Type and Condition ..................................... NCHRP 350 Strong Soil, dry ASI ............................................................................ 0.7 Test Vehicle Post-Impact Vehicular Behavior (deg - rate gyro) Type ........................................................................... Production Model Maximum Roll Angle .............................................. 6.5 Designation ............................................................... 2000P Maximum Pitch Angle ............................................ -10.2 Model......................................................................... 1998 GMC Maximum Yaw Angle .............................................. -52.0 ............................................................................ 3/4 Ton Pickup Test Article Deflections (m) Mass (kg) Dynamic .................................................................... 0.5 Curb .................................................................. 1975 Permanent................................................................. 0.4 Test inertial ....................................................... 1993 Vehicle Damage (Primary Impact) Impact Conditions Exterior Speed (km/h) ............................................................ 85.6 VDS.................................................................... RFQ-3 Angle (deg) ................................................................ 25 CDC ................................................................... 01RFWE2 Impact Severity (kJ) .............................................. 100.6 Interior VCDI ................................................................. AS0000000 Maximum Deformation (mm) ......................... Negligible Figure 37. Summary of curbguardrail crash test 52-2556-001, B curb below guardrail.

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t = 0.000 sec t = 0.144 sec t = 0.288 sec t = 0.432 sec t = 0.576 sec t = final Type B SGR04a Guardrail General Information Test Agency ............................................................... E-TECH Testing Services, Inc. Test Designation ...................................................... NCHRP 350 Test 3-11 (modified) Exit conditions Test No. ..................................................................... 52-2556-002 Speed (km/h) ............................................................ N/A Date............................................................................ 6/18/03 Angle (deg - veh. c.g.) .............................................. N/A Test Article Occupant Risk Values Curb Type ................................................................. AASHTO Type B Impact Velocity (m/s) Barrier Length ....................................................... 53.34 m (overall) x-direction ........................................................ 5.5 Height (mm - relative to approach) ...................... 550 y-direction ........................................................ -3.2 Setback (m - relative to curb) ............................... 2.5 Ridedown Acceleration (g's) Material and key elements ...................................... AASHTO SGR04a Guardrail with x-direction ......................................................... -10.8 ............................................................................ SEW02a End Terminal equipped y-direction ......................................................... 11.4 ............................................................................ Re-Block recycled plastic blockouts European Committee for Normalization (CEN) Values ............................................................................ of 50% HDPE / 50% PP THIV (km/h) ............................................................. 22.4 PHD (g's) ................................................................... 14.7 Foundation Type and Condition ..................................... NCHRP 350 Strong Soil, dry ASI ............................................................................ 0.8 Test Vehicle Post-Impact Vehicular Behavior (deg - rate gyro) Type ........................................................................... Production Model Maximum Roll Angle .............................................. 472.1 Designation ............................................................... 2000P Maximum Pitch Angle ............................................ 26.9 Model......................................................................... 1994 Chevrolet Maximum Yaw Angle .............................................. 20.3 ............................................................................ 3/4 Ton Pickup Test Article Deflections (m) Mass (kg) Dynamic .................................................................... 0.6 Curb .................................................................. 1919 Permanent................................................................. 0.4 Test inertial ....................................................... 2002 Vehicle Damage (Primary Impact) Impact Conditions Exterior Speed (km/h) ............................................................ 86.6 VDS.................................................................... R&T-5/RFQ-4 Angle (deg) ................................................................ 25 CDC ................................................................... 01RFE03 Impact Severity (kJ) .............................................. 103.5 Interior VCDI ................................................................. RF0000010 Maximum Deformation (mm) ......................... 330 Figure 38. Summary of curbguardrail crash test 52-2556-002, B curb offset 2.5 m from guardrail. 77

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78 t = 0.000 sec t = 0.096 sec t = 0.192 sec t = 0.288sec t = 0.384 sec t = final Type T100 Curb SGR04a Guardrail General Information Test Agency ............................................................... E-TECH Testing Services, Inc. Test Designation ...................................................... NCHRP 350 Test 3-11 (modified) Exit conditions Test No. ..................................................................... 52-2556-003 Speed (km/h) ............................................................ N/A Date............................................................................ 7/21/2003 Angle (deg - veh. c.g.) .............................................. N/A Test Article Occupant Risk Values Curb Type ................................................................. New York T100 Impact Velocity (m/s) Barrier Length ....................................................... 53.34 m (overall) x-direction ........................................................ 5.6 Height (mm - relative to approach) ...................... 550 y-direction ........................................................ -3.0 Setback (m - relative to curb) ............................... 2.5 Ridedown Acceleration (g's) Material and key elements ...................................... AASHTO SGR04a Guardrail with x-direction ......................................................... -6.1 ............................................................................ SEW02a End Terminal equipped y-direction ......................................................... -4.3 ............................................................................ Re-Block recycled plastic blockouts European Committee for Normalization (CEN) Values ............................................................................ of 50% HDPE / 50% PP THIV (km/h) ............................................................. 22.0 PHD (g's) ................................................................... 6.6 Foundation Type and Condition ..................................... NCHRP 350 Strong Soil, dry ASI ............................................................................ 0.6 Test Vehicle Post-Impact Vehicular Behavior (deg - rate gyro) Type ........................................................................... Production Model Maximum Roll Angle .............................................. -41.9 Designation ............................................................... 2000P Maximum Pitch Angle ............................................ -32.5 Model......................................................................... 1994 GMC Maximum Yaw Angle .............................................. 95.5 ............................................................................ 3/4 Ton Pickup Test Article Deflections (m) Mass (kg) Dynamic .................................................................... 0.4 Curb .................................................................. 1940 Permanent................................................................. 0.3 Test inertial ....................................................... 1994 Vehicle Damage (Primary Impact) Impact Conditions Exterior Speed (km/h) ............................................................ 80.0 VDS.................................................................... RFQ-3 Angle (deg) ................................................................ 25 CDC ................................................................... 01RFWW1 Impact Severity (kJ) .............................................. 87.8 Interior VCDI ................................................................. AS0000000 Maximum Deformation (mm) ......................... 74 Figure 39. Summary of curbguardrail crash test at 80 km/h 52-2556-003, NY curb offset 2.5 m from guardrail, guardrail height 550 mm.

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79 and the vehicle engaged two W-beam rails. The vehicle sub- E-TECH Test 52-2556-006 is summarized in Figure 42. In sequently damaged two downstream posts and one section of this test, the vehicle bumper contacted the guardrail 1.9 m rail. The vehicle slid to a stop 24 m downstream of its posi- upstream of the connection splice at Post 15. The right cor- tion at impact, straddling the rail. The vehicle sustained ner of the bumper came into contact with the W-beam guard- minor dents in the bumper and right front fender, a major rail. The blockouts supported the W-beam and began loading dent in the bed on the driver side, major damage to the front the posts laterally. The W-beam flattened out, forming a rib- right wheel and suspension, and a bent frame. There was no bon that engaged the vehicle. As the W-beam deflected lat- windshield contact or damage, and a maximum 74-mm defor- erally it developed tension that forced the vehicle to yaw mation of the vehicle interior at the toe pan area on the pas- counterclockwise. Maximum dynamic deformation of the senger side. guardrail was 0.5 m, and the permanent deformation was E-TECH Test 52-2556-004 is summarized in Figure 40. In 0.3 m. In the initial impact, the right front wheel forced posts this test, the vehicle contacted the curb and the suspension 15 and 16 to deform and the vehicle engaged two W-beam compressed at first and then extended during the traverse. rails. The vehicle slid to a stop 22 m downstream of its posi- The body of the vehicle was noticeably elevated, but the tires tion at impact and came to rest against the downstream sec- remained in contact with the ground. The vehicle bumper tion of guardrail. The pickup sustained minor dents in the contacted the guardrail just upstream of the connection splice bumper and right front fender, a major dent in the bed on the at Post 15. The right corner of the bottom surface of the driver's side, major damage to the front right wheel and sus- bumper came into contact with the top edge of the W-beam pension, and the frame was bent. There was no windshield guardrail. The blockouts supported the W-beam and began contact or damage, and negligible deformation of the vehicle loading the posts laterally. The front overhang of the vehicle interior. rose up over the guardrail and the guardrail came to bear E-TECH Test 52-2556-007 is summarized in Figure 43. In against the right front wheel. All four wheels became air- this test, the vehicle bumper contacted the guardrail 2.5 m borne, and the vehicle pitched up and passed over the guard- upstream of the connection splice at Post 15. The right cor- rail with relatively minor change in direction. The vehicle ner of the bumper came into contact with the W-beam guard- landed behind the guardrail and remained upright. The vehi- rail. The blockouts supported the W-beam and began loading cle slid to a stop 36 m downstream and 3.8 m to the right of the posts laterally. The W-beam flattened out, forming a rib- its position at impact. Maximum dynamic deformation of the bon that engaged the vehicle. As the W-beam deflected later- guardrail was 0.4 m, and the permanent deformation was ally it developed tension that forced the vehicle to yaw coun- 0.3 m. The pickup sustained minor dents in the bumper and terclockwise. Maximum dynamic deformation of the guardrail was 0.7 m, and the permanent deformation was 0.4 m. In the right front fender and major damage to the front right wheel initial impact, the right front wheel forced posts 15 and 16 to and suspension, and the frame was bent. There was no wind- deform and the vehicle engaged two W-beam rails. The vehi- shield contact or damage, and negligible deformation of the cle slid to a stop 30 m downstream of its position at impact vehicle interior. and came to rest against the downstream section of guardrail. E-TECH Test 52-2556-005 is summarized in Figure 41. In The pickup sustained minor dents in the bumper and right this test, the vehicle bumper contacted the guardrail 0.6 m front fender, a major dent in the bed on the driver's side, and upstream of the connection splice at Post 15. The right cor- major damage to the front right wheel and suspension; the ner of the bumper came into contact with the W-beam guard- frame was bent. There was no windshield contact or damage, rail. The blockouts supported the W-beam and began loading and negligible deformation of the vehicle interior. the posts laterally. The W-beam flattened out, forming a rib- In all the tests, the damage to the guardrail was catego- bon that engaged the vehicle. As the W-beam deflected later- rized as substantial since one or more replacement posts ally, it developed tension that forced the vehicle to yaw coun- and W-beam sections would be needed for repair. Most other terclockwise. Maximum dynamic deformation of the guardrail components of the installations were judged reusable. was 0.6 m and the permanent deformation was 0.5 m. Posts 15 through 17 were deformed. The vehicle traversed four W-beam rails before losing contact with the installation. The Summary of Crash Test Results vehicle exit angle was 12 degrees relative to the installation centerline when it lost contact with the barrier. The exit veloc- The results of the seven full-scale crash tests were evaluated ity of the vehicle was 43.3 km/h. The emergency braking sys- using the structural adequacy, occupant risk, and vehicle tra- tem was applied after loss of contact, and the vehicle skidded jectory evaluation criteria for longitudinal barrier Test 11 from to a stop 27 m downstream and 2 m left of its position at NCHRP Report 350, as shown in Table 39. Note that the eval- impact. The pickup sustained minor dents in the bumper and uations of the test results were based on the nominal impact right front fender and major damage to the front right wheel speeds. The relevant evaluation criteria were as follows: and suspension, and the frame was bent. There was no wind- shield contact or damage, and negligible deformation of the Test article should contain and redirect the vehicle; the vehicle interior. vehicle should not penetrate, underride, or override the

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80 t = 0.144 sec t = 0.288 sec t = 0.432 sec t = 0.576 sec t = final SGR04a Guardrail New York Type T100 Curb General Information Test Agency ............................................................... E-TECH Testing Services, Inc. Test Designation ...................................................... NCHRP 350 Test 3-11 (modified) Exit conditions Test No. ..................................................................... 52-2556-004 Speed (km/h) ............................................................ N/A Date............................................................................ 8/14/2003 Angle (deg - veh. c.g.) .............................................. N/A Test Article Occupant Risk Values Curb Type ................................................................. New York T100 Impact Velocity (m/s) Barrier Length ....................................................... 53.34 m (overall) x-direction ........................................................ 4.7 Height (mm - relative to approach) ...................... 550 y-direction ........................................................ -3.6 Setback (m - relative to curb) ............................... 4.5 Ridedown Acceleration (g's) Material and key elements ...................................... AASHTO SGR04a Guardrail with x-direction ......................................................... -4.1 ............................................................................ SEW02a End Terminal equipped y-direction ......................................................... -4.9 ............................................................................ Re-Block recycled plastic blockouts European Committee for Normalization (CEN) Values ............................................................................ of 50% HDPE / 50% PP THIV (km/h) ............................................................. 20.8 PHD (g's) ................................................................... 5.2 Foundation Type and Condition ..................................... NCHRP 350 Strong Soil, dry ASI ............................................................................ 0.6 Test Vehicle Post-Impact Vehicular Behavior (deg - rate gyro) Type ........................................................................... Production Model Maximum Roll Angle .............................................. 31.9 Designation ............................................................... 2000P Maximum Pitch Angle ............................................ 11.4 Model......................................................................... 1989 GMC Maximum Yaw Angle .............................................. -12.9 ............................................................................ 3/4 Ton Pickup Test Article Deflections (m) Mass (kg) Dynamic .................................................................... 0.4 Curb .................................................................. 1947 Permanent................................................................. 0.3 Test inertial ....................................................... 2014 Vehicle Damage (Primary Impact) Impact Conditions Exterior Speed (km/h) ............................................................ 81.3 VDS.................................................................... RFQ-3 Angle (deg) ................................................................ 23 CDC ................................................................... 01RFEW3 Impact Severity (kJ) .............................................. 78.4 Interior VCDI ................................................................. AS0000000 Maximum Deformation (mm) ......................... Negligible Figure 40. Summary of curbguardrail crash test 52-2556-004, NY curb offset 4.5 m from guardrail, guardrail height 550 mm.

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t = 0.000 sec t = 0.192 sec t = 0.384 sec t = 0.576 sec t = 0.768 sec t = final SGR04a Guardrail New York Type T100 Curb General Information Test Agency ............................................................... E-TECH Testing Services, Inc. Test Designation ...................................................... NCHRP 350 Test 3-11 (modified) Exit conditions Test No. ..................................................................... 52-2556-005 Speed (km/h) ............................................................ 43.3 Date............................................................................ 9/5/2003 Angle (deg - veh. c.g.) .............................................. 12 Test Article Occupant Risk Values Curb Type ................................................................. New York T100 Impact Velocity (m/s) Barrier Length ....................................................... 53.34 m (overall) x-direction ........................................................ 4.2 Height (mm - relative to approach) ...................... 550 y-direction ........................................................ -3.8 Setback (m - relative to curb) ............................... 4.5 Ridedown Acceleration (g's) Material and key elements ...................................... AASHTO SGR04a Guardrail with x-direction ......................................................... -7.6 ............................................................................ SEW02a End Terminal equipped y-direction ......................................................... -5.8 ............................................................................ Re-Block recycled plastic blockouts European Committee for Normalization (CEN) Values ............................................................................ of 50% HDPE / 50% PP THIV (km/h) ............................................................. 19.4 PHD (g's) ................................................................... 9.1 Foundation Type and Condition ..................................... NCHRP 350 Strong Soil, dry ASI ............................................................................ 0.5 Test Vehicle Post-Impact Vehicular Behavior (deg - rate gyro) Type ........................................................................... Production Model Maximum Roll Angle .............................................. -8.9 Designation ............................................................... 2000P Maximum Pitch Angle ............................................ -4.9 Model......................................................................... 1994 Chevrolet Maximum Yaw Angle .............................................. -37.2 ............................................................................ C2500 Pickup Test Article Deflections (m) Mass (kg) Dynamic .................................................................... 0.6 Curb .................................................................. 1904 Permanent................................................................. 0.5 Test inertial ....................................................... 1999 Vehicle Damage (Primary Impact) Impact Conditions Exterior Speed (km/h) ............................................................ 80.5 VDS.................................................................... RFQ-3 Angle (deg) ................................................................ 24 CDC ................................................................... 01RFEW3 Impact Severity (kJ) .............................................. 82.7 Interior VCDI ................................................................. AS0000000 Maximum Deformation (mm) ......................... Negligible Figure 41. Summary of curbguardrail crash test 52-2556-005, NY curb offset 4.5 m from guardrail, guardrail height 650 mm. 81

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82 t = 0.0000 sec t = 0.2400 sec t = 0.4800 sec t = 0.7200sec t = 0.9600 sec t = final SGR04a Guardrail New York Type T100 Curb General Information Test Agency ............................................................... E-TECH Testing Services, Inc. Exit conditions Test Designation ...................................................... NCHRP 350 Test 2-11 Speed (km/h) ............................................................ 36.5 Test No. ..................................................................... 52-2556-006 Angle (deg - veh. c.g.) .............................................. 12 Date............................................................................ 10/7/2003 Occupant Risk Values Test Article Impact Velocity (m/s) Curb Type ................................................................. New York T100 x-direction ........................................................ 4.2 Barrier Length ....................................................... 53.34 m (overall) y-direction ........................................................ -4.2 Height (mm - relative to approach) ...................... 650 Ridedown Acceleration (g's) Setback (m - relative to curb) ............................... 2.5 x-direction ......................................................... -5.3 Material and key elements ...................................... AASHTO SGR04a Guardrail with y-direction ......................................................... -5.0 ............................................................................ SEW02a End Terminal equipped European Committee for Normalization (CEN) Values ............................................................................ Re-Block recycled plastic blockouts THIV (km/h) ............................................................. 19.6 ............................................................................ of 50% HDPE / 50% PP PHD (g's) ................................................................... 7.3 Foundation Type and Condition ..................................... NCHRP 350 Strong Soil, dry ASI ............................................................................ 0.5 Test Vehicle Post-Impact Vehicular Behavior (deg - rate gyro) Type ........................................................................... Production Model Maximum Roll Angle .............................................. 6.9 Designation ............................................................... 2000P Maximum Pitch Angle ............................................ -7.2 Model......................................................................... 1990 Chevrolet Maximum Yaw Angle .............................................. -39.2 ............................................................................ C2500 Pickup Test Article Deflections (m) Mass (kg) Dynamic .................................................................... 0.5 Curb .................................................................. 1862 Permanent................................................................. 0.3 Test inertial ....................................................... 2007 Vehicle Damage (Primary Impact) Impact Conditions Exterior Speed (km/h) ............................................................ 69.6 VDS.................................................................... RFQ-3 Angle (deg) ................................................................ 25 CDC ................................................................... 01RFEW3 Impact Severity (kJ) .............................................. 67.0 Interior VCDI ................................................................. AS0000000 Maximum Deformation (mm) ......................... Negligible Figure 42. Summary of curbguardrail crash test 52-2556-006, nominal speed 70 km/h, NY curb offset 2.5 m from guardrail.

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t = 0.0000 sec t = 0.144 sec t = 0.288sec t = 0.432sec t = 0.576 sec t = final SGR04a Guardrail New York Type T100 Curb General Information Exit conditions Test Agency ............................................................... E-TECH Testing Services, Inc. Speed (km/h) ............................................................ 41.8 Test Designation ...................................................... NCHRP 350 Test 3-11 (modified) Angle (deg - veh. c.g.) .............................................. 15 Test No. ..................................................................... 52-2556-007 Occupant Risk Values Date............................................................................ 12/4/03 Impact Velocity (m/s) Test Article x-direction ........................................................ 5.0 Curb Type ................................................................. New York T100 y-direction ........................................................ -4.3 Barrier Length ....................................................... 53.34 m (overall) Ridedown Acceleration (g's) Height (mm - relative to approach) ...................... 650 x-direction ......................................................... -10.0 Setback (m - relative to curb) ............................... 2.5 y-direction ......................................................... -17.8 Material and key elements ...................................... AASHTO SGR04a Guardrail with European Committee for Normalization (CEN) Values ............................................................................ SEW02a End Terminal equipped THIV (km/h) ............................................................. 20.7 ............................................................................ Re-Block recycled plastic blockouts PHD (g's) ................................................................... 17.8 ............................................................................ of 50% HDPE / 50% PP ASI ............................................................................ 0.8 Foundation Type and Condition ..................................... NCHRP 350 Strong Soil, drained Post-Impact Vehicular Behavior (deg - rate gyro) Test Vehicle Maximum Roll Angle .............................................. 17.0 Type ........................................................................... Production Model Maximum Pitch Angle ............................................ -17.3 Designation ............................................................... 2000P Maximum Yaw Angle .............................................. -40.2 Model......................................................................... 1994 GMC Test Article Deflections (m) ............................................................................ C2500 Pickup Dynamic .................................................................... 0.7 Mass (kg) Permanent................................................................. 0.4 Curb .................................................................. 1870 Vehicle Damage (Primary Impact) Test inertial ....................................................... 2001 Exterior Impact Conditions VDS.................................................................... RFQ-3 Speed (km/h) ............................................................ 85.6 CDC ................................................................... 01RFEW3 Angle (deg) ................................................................ 25 Interior Impact Severity (kJ) .............................................. 101.0 VCDI ................................................................. AS0000000 Maximum Deformation (mm) ......................... Negligible Figure 43. Summary of curbguardrail crash test 52-2556-007, nominal speed 85 km/h, NY curb offset 2.5 m from guardrail. 83