Figures (10)  Tables (7)

    • Figure 1. 

      The framework of the proposed method.

    • Figure 2. 

      FT-BN conversion diagram.

    • Figure 3. 

      The structure of the fault tree.

    • Figure 4. 

      The structure of the Bayesian network.

    • Figure 5. 

      Predictive inference of the BN.

    • Figure 6. 

      Diagnostic inference of the BN with 100% probability of the leaf node.

    • Figure 7. 

      The ROV ranking for the 20 root nodes.

    • Figure 8. 

      The BIM ranking for the 20 root nodes.

    • Figure 9. 

      The RRW ranking for the 20 root nodes.

    • Figure 10. 

      The ranking comparison of all root node metrics.

    • Risk level Triangular fuzzy number
      $l'$ $m'$ $u'$
      Very low (VL) 0 0 0.1
      Low (L) 0 0.1 0.3
      Fairly low (FL) 0.1 0.3 0.5
      Medium(M) 0.3 0.5 0.7
      Fairly high (FH) 0.5 0.7 0.9
      High (H) 0.7 0.9 1.0
      Very high (VH) 0.9 1.0 1.0

      Table 1. 

      Risk level and probability expression.

    • No. Accident time Accident location Accident feature Accident brief
      1 November 24,
      2011      		 Sanshankou Section, 312 National Highway, Jingyuan County Winter, national highway, noon, clear The LNG tanker truck overturned due to brake failure caused by icing.
      2 April 21, 2012 1,350 km + 800 m mark, 310 National Highway, Tianshui City, Gansu Spring, national highway The LNG tanker rolled over from the highway onto the Wei River beach, approximately 10 m from the roadbed. A minor leak occurred at the tank valve.
      3 May 26, 2014 Entrance No. 1 Tunnel, Fuyin Expressway, Tongchuan Summer, highway, afternoon Spontaneous combustion of the rear tires of the LNG tanker caused it to overturn, resulting in the valve being burnt out and causing a leak.
      4 February 3, 2015 1,020 km mark, 314 National Highway, Aksu City, Xinjiang Spring, national highway, nighttime, snowy The driver lost control due to slippery road conditions in heavy snow, leading to an overturn and leakage. A significant amount of natural gas leaked.
      5 October 11, 2016 Downhill section under Liujiagou Viaduct, Qingyin Expressway, Wubu County, Yulin Autumn, expressway, morning, clear Excessive speed caused the tank to tilt due to inertia, leading to the tanker overturning. The tanker's pipeline ruptured, resulting in an LNG leak.
      6 February 20, 2017 1 km from Ma'anshan Tunnel towards Nanhua, Nanshui Highway, Nanhua County, Yunnan Spring, provincial highway, morning, clear A tanker carrying 24 tons of LNG overturned into a roadside ditch.
      7 May 11, 2017 Section 2,058 km, Lantian Tunnel Summer, expressway tunnel, nighttime, clear A tanker carrying 21 tons of LNG, while avoiding a vehicle ahead, had its left front tire hit the roadbed and burst, causing it to overturn and skid.
      8 April 29, 2019 East of Duzhuang Natural Village, Gaoxin Village, Gaoxin Town, Suiyang District, Shangqiu City Spring, county road, morning, clear An LNG tanker carrying 21.6 tons of LNG overturned due to improper driving.
      9 April 7, 2020 Huangjiashan at 2,548 km mark Spring, national highway, nighttime, clear A fully loaded 20-ton tanker overturned while navigating a U-shaped curve due to driver error, compounded by rain, darkness, and slippery road conditions. The leak originated from the rear of the storage tank. The leaked natural gas mixed with atmospheric moisture, forming a white mist.
      10 June 7, 2020 Shaxi Section, Yongjin Expressway (towards Jinhua), Xinchang County, Zhejiang Summer, expressway, nighttime, clear An LNG tanker rear-ended another vehicle, overturned, and caught fire.
      11 June 13, 2020 Off-ramp at Wenling West Exit (Wenzhou direction), Shenhai Expressway Summer, expressway, afternoon, clear A tanker transporting hazardous chemicals overturned on an off-ramp due to overspeeding. Subsequent impacts led to an explosion.
      12 June 20, 2021 Xiajing Village Section, Qiaodong Town, Zhao'an County, Zhangzhou City, National Highway 324 Summer, national highway, early morning, clear A 26-ton tanker was involved in a rear-end collision with a vehicle, resulting in a natural gas leak.

      Table 2. 

      LNG road tanker rollover accident cases.

    • Items Categories Score
      Volume < 600 1
      600~1,000 2
      Source Transportation department 4
      Comprehensive materials 2
      Urban traffic accidents 1
      Subject Mountainous highway accidents 2
      Major/catastrophic accidents 4
      Hazardous materials tanker accidents 5
      Vehicles involved All kinds of vehicles 2
      Heavy-duty vehicles/tank trucks 4
      Level of detail Detailed 2
      Rough 4

      Table 3. 

      Score allocation for the evaluation of sources of accident-causative factors.

    • Number Date source Score for volume Score for source Score for subject Score for vehicles involved Score for level of detail Total score Final weight
      1 Heavy-duty truck accidents 1 4 1 4 4 14 0.19
      2 Mountainous highway accidents 1 4 2 2 2 11 0.15
      3 Major/catastrophic accidents 1 4 4 2 4 15 0.20
      4 Hazardous materials tanker accidents 2 2 5 4 2 15 0.20
      5 Expert evaluations 2 4 5 4 4 19 0.26

      Table 4. 

      Weight allocation for the evaluation of five groups of accident causative factors.

    • Symbol Description Judgment Aggregation of fuzzy numbers Defuzzification
      1 2 3 4 5
      X1 Traffic violation M M H FL FH (0.39, 0.59, 0.77) 0.5870
      X2 Unsafe driving M M FH FL H (0.4, 0.6, 0.78) 0.5975
      X3 Lack of experience and erroneous maneuvers L FL FH FL M (0.21, 0.39, 0.59) 0.3988
      X4 Low visibility L L FL L L (0.02, 0.14, 0.34) 0.1600
      X5 Unfavorable driving time M M M M L (0.22, 0.4, 0.6) 0.4025
      X6 Poor road alignment L M M L H (0.29, 0.45, 0.62) 0.4513
      X7 Poor road surface smoothness VL VL VL VL L (0, 0.03, 0.15) 0.0510
      X8 Slippery road surface FL L FL L M (0.12, 0.28, 0.48) 0.2908
      X9 Tire blowouts and tire failures VL VL VL VL VL (0, 0, 0.1) 0.0250
      X10 Sudden failure of brakes or steering FL VL FL VL L (0.04, 0.14, 0.31) 0.1583
      X11 Non-compliance with transport requirements VL VL VL VL L (0, 0.03, 0.15) 0.0510
      X12 Improper loading and cargo securement VL VL VL VL FL (0.03, 0.08, 0.2) 0.0965
      X13 Low-adhesion (e.g., ice/snow cover) VL VL L VL FL (0.03, 0.1, 0.24) 0.1165
      X14 Road construction and obstacles VL VL VL VL L (0, 0.03, 0.15) 0.0510
      X15 Absence of critical traffic facilities L L M FL L (0.08, 0.22, 0.42) 0.2350
      X16 Visibility less than 100 m L L L L L (0, 0.1, 0.3) 0.1250
      X17 Adverse weather conditions (e.g., heavy fog) L L L L VL (0, 0.07, 0.25) 0.0990
      X18 Nighttime driving without illumination L FL VL L L (0.02, 0.11, 0.29) 0.1313
      X19 visual interference VL VL VL VL VL (0, 0, 0.1) 0.0250
      X20 Complex traffic flow M VL VL VL L (0.06, 0.12, 0.27) 0.1413

      Table 5. 

      Prior probability from historical data and experts' estimation.

    • X19 X20 P(M15 = yes|X19,X20) P(M15 = no|X19,X20)
      No No 0 1
      No Yes 0 1
      yes No 0 1
      Yes Yes 1 0

      Table 6. 

      The CPT of the node M15.

    • X10 X11 P(M9 = yes|X10,X11) P(M9 = no|X10,X11)
      No No 0 1
      No Yes 1 0
      Yes No 1 0
      Yes Yes 1 0

      Table 7. 

      The CPT of the node M9.