Guidelines for Traversability of Roadside Slopes (2019) / Chapter Skim
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Pages 79-112
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From page 79... ...
79 As part of this research, several full-scale vehicle traversability tests were performed on a 1V:3H slope. These tests were performed to evaluate the performance of the simulation vehicle models on slopes.
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80 Guidelines for Traversability of Roadside Slopes The full-scale test matrix and the test site cross section are presented in Figure 6.1. The encroachment speeds varied between 35 and 55 mph and the encroachment angles varied between 5 and 10 degrees, as shown in the figure.
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Vehicle Testing on Slope 81 maximum lateral friction coefficients. The minimum value of the coefficient was selected to be 0.5, which is typical for grassy surface.
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82 Guidelines for Traversability of Roadside Slopes (a) Vehicle simulations start.
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Vehicle Testing on Slope 83 Figure 6.3. Vehicle kinematics of pickup trucks encroaching at 55 mph and 5-degree angle with different terrain coefficients.
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84 Guidelines for Traversability of Roadside Slopes Figure 6.4. Vehicle kinematics of pickup trucks encroaching at 35 mph and 5-degree angle with different terrain coefficients.
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Vehicle Testing on Slope 85 Figure 6.5. Vehicle kinematics of small cars encroaching at 45 mph and 10-degree angle with different terrain coefficients.
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86 Guidelines for Traversability of Roadside Slopes MuY 0.5 MuY 1.0 MuY 1.5 MuY 2.0 Figure 6.6. Vehicle kinematics of small cars encroaching at 55 mph and 5-degree angle with different terrain coefficients.
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Vehicle Testing on Slope 87 6.3 Vehicle Traversal Tests To perform the vehicle traversal tests, a ditch was constructed with a 1V:3H foreslope, as previously described in Figure 6.1. The cross section of the ditch and its photograph are shown in Figure 6.7.
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From page 88... ...
88 Guidelines for Traversability of Roadside Slopes As in the computer simulations, a PRT of 1 s was used prior to applying any steering or braking input. The PRT of 1 s window began once the vehicle's leading bumper corner was a shoulder width away from the top edge of the ditch foreslope.
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From page 89... ...
Vehicle Testing on Slope 89 Date: 2015-07-26 Test No.: 479310-1-1 thru 3 VIN No.: 3GCEC13J58G211693 Year: 2008 Make: Chevrolet Model: C1500 Tire Size: P275/55R20 Tire Inflation Pressure: 35 psi Tread Type: Highway Odometer: 176414 Note any damage to the vehicle prior to test: None Geometry: inches A 80.0 F 39.4 K 20.2 P 3.0 U 29.0 B 72.5 G 28.5 L 29.8 Q 31.0 V 26.0 C 230.1 H 57.0 M 68.5 R 21.5 W 56.9 D 47.2 I 12.5 N 67.5 S 16.0 X 82.5 E 46.5 J 27.2 O 45.5 T 45.5 Wheel Center Height Front 14.75 Wheel Well Clearance (Front) 5.25 Bottom Frame Height - Front 17.125 Wheel Center Height Rear 14.75 Wheel Well Clearance (Rear)
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From page 90... ...
90 Guidelines for Traversability of Roadside Slopes Date: 2015-07-20 Test No.: 479340-1-4 thru 6 VIN No.: KNADE223096524486 Year: 2009 Make: Kia Model: Rio Tire Inflation Pressure: 32 psi Odometer: 110248 Tire Size: Describe any damage to the vehicle prior to test: None Geometry: inches A 66.38 F 33.00 K 12.50 P 4.12 U 14.00 B 58.00 G -- -- -- L 25.00 Q 27.19 V 21.00 C 165.75 H 61.62 M 57.75 R 15.38 W 44.00 D 34.00 I 8.50 N 57.12 S 7.75 X 108.50 E 98.75 J 21.50 O 31.50 T 66.12 Wheel Center Ht Front 11.00 Wheel Center Ht Rear 11.00 Allowable TIM = 2420 lb ±55 lb | Allowable GSM = 2585 lb ± 55 lb Mass Distribution: lb LF: 858 RF: 761 LR: 456 RR: 502 Denotes accelerometer location. NOTES: None Engine Type: 4 cylinder Engine CID: 1.6 liter Transmission Type: x Auto or Manual x FWD RWD 4WD Optional Equipment: None Dummy Data: Type: None Mass: NA Seat Position: NA GVWR Ratings: Mass: lb Curb Test Inertial Gross Static Front 1918 Mfront 1584 1619 Back 1874 Mrear 864 958 Total 3638 MTotal 2448 2577 Figure 6.10.
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Vehicle Testing on Slope 91 Because the brakes were not applied in this test, the vehicle then started rolling backwards into the ditch and reached the ditch bottom. The traversal of the vehicle in this test is shown in Figure 6.12.
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92 Guidelines for Traversability of Roadside Slopes 2.450 s 3.065 s 2.458 s 1.823 s 2.100 s 1.400 s 1.750 s Figure 6.12. (Continued)
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Vehicle Testing on Slope 93 0.000 s 0.350 s 0.700 s 1.050 s 1.400 s 1.750 s 2.100 s 2.450 s Figure 6.13. Sequential photographs for Test No.
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94 Guidelines for Traversability of Roadside Slopes 2.800 s 3.150 s 3.500 s 3.850 s 4.200 s 4.550 s 4.900 s 5.250 s Figure 6.13. (Continued)
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Vehicle Testing on Slope 95 In test 479340-1-3, the pickup truck encroached onto the 6-ft shoulder offset at a speed and angle of 55.47 mph and 5.53 degrees, respectively. The right front tire of the pickup truck entered the ditch at 0.906 s, whereas the left rear tire entered the ditch at 1.662 s.
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96 Guidelines for Traversability of Roadside Slopes 0.000 s 0.350 s 0.700 s 1.050 s 1.400 s 1.750 s 2.100 s 2.450 s Figure 6.14. Sequential photographs for Test No.
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Vehicle Testing on Slope 97 2.800 s 3.150 s 3.500 s 3.850 s 4.200 s 4.550 s 4.900 s 5.250 s Figure 6.14. (Continued)
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98 Guidelines for Traversability of Roadside Slopes 0.000 s 0.350 s 0.700 s 1.050 s 1.400 s 1.750 s 2.100 s 2.450 s Figure 6.15. Sequential photographs for Test No.
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Vehicle Testing on Slope 99 2.800 s 3.150 s 3.500 s 4.200 s 4.550 s 4.900 s 3.850 s Figure 6.15. (Continued)
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100 Guidelines for Traversability of Roadside Slopes 0.000 s 0.350 s 0.700 s 1.050 s 1.400 s 1.750 s 2.100 s 2.450 s Figure 6.16. Sequential photographs for Test No.
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Vehicle Testing on Slope 101 2.800 s 3.150 s 3.850 s 4.200 s 3.500 s Figure 6.16. (Continued)
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102 Guidelines for Traversability of Roadside Slopes 0.000 s 0.350 s 0.700 s 1.050 s 1.400 s 1.750 s 2.100 s 2.450 s Figure 6.17. Sequential photographs for Test No.
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Vehicle Testing on Slope 103 2.800 s 3.150 s 3.850 s 4.200 s 3.500 s Figure 6.17. (Continued)
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104 Guidelines for Traversability of Roadside Slopes Because of the high ratio of loose aggregate on the foreslope, the ABS brakes of the vehicles were not very effective. ABS brakes are designed to release if the wheel locks and the tire slips in the longitudinal direction.
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Vehicle Testing on Slope 105 1.050 s 1.750 s 2.100 s 3.065 s Figure 6.18. Test (left)
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106 Guidelines for Traversability of Roadside Slopes 1.050 s 2.450 s 3.500 s 5.250 s Figure 6.19. Test (left)
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Vehicle Testing on Slope 107 1.400 s 2.450 s 3.500 s 4.900 s Figure 6.20. Test (left)
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108 Guidelines for Traversability of Roadside Slopes 0.700 s 1.750 s 2.800 s 3.500 s Figure 6.21. Test (left)
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Vehicle Testing on Slope 109 0.700 s 1.750 s 2.800 s 4.200 s Figure 6.22. Test (left)
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110 Guidelines for Traversability of Roadside Slopes 0.700 s 1.400 s 2.450 s 4.200 s Figure 6.23. Test (left)
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Vehicle Testing on Slope 111 (a)
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112 Guidelines for Traversability of Roadside Slopes Figure 6.25. Comparison of vehicle path for tests with small car.
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