Analysis of traffic safety in airport aircraft activity areas based on bayesian networks and fault trees

Ruijun Guo; Jiawen Wu; Fan Ji; Wanxiang Wang; Yuan Yin; Ruijun Guo; Jiawen Wu; Fan Ji; Wanxiang Wang; Yuan Yin

doi:10.48130/dts-0024-0002

Type	Influencing factor	Explanation	Variable setting
Driver	S1 Fatigue factor	Fatigue of the driver	0: negligible; 1: acceptable; 2: unacceptable.
	S2 Time pressure factor	Situations where pilots are under time pressure to secure flights	0: acceptable; 1: unacceptable;
	S3 Correct operation of special equipment factors	Whether the driver has violated the law or operated the vehicle's special equipment improperly	0: acceptable; 1: illegal operation of special vehicle equipment
	S4 Driving violation factor	Whether the driver in the process of driving does not follow the prescribed route, speeding and other violations	0: acceptable; 1. illegal driving
Pedestrian	S5 Pedestrian visibility factor	Whether pedestrians on the road can attract the attention of drivers in time	0: good visibility; 1: poor visibility
	S5A Pedestrians wearing reflective vests	Pedestrians who wear reflective vests as required can greatly improve their own visibility	0: yes; 1: no
	S6 Physiological factor	The physical condition of the pedestrian	0: acceptable; 1: not acceptable
	S7 The choice of walking route	The walking of pedestrians in accordance with the prescribed route	0: acceptable; 1: not walking on the prescribed route
	S8 Unqualified illegal operation	Whether unqualified personnel illegally drive motor vehicles or illegally operate special equipment	0: acceptable; 1: illegal operation of unqualified personnel
Other personnel	S9 Passengers or non-staff	Whether passengers or other non-staff members stray into the aircraft activity area and become uncontrolled	0: acceptable; 1: there were passengers straying into the activity area and it was not controlled
Vehicle	S10 Vehicle technical status	Including vehicle steering system, driving system, braking system, electrical system and so on	0: in good condition; 1: poor state
	S11 Vehicle identification	Visibility of vehicles on the road	0: in good condition; 1: poor state
	S11A Vehicle installation of reflective warning signs	Refers to whether the vehicle is equipped with safety warning lights and reflective warning signs as required	0: yes; 1: no
	S12 Vehicle dimensions	Whether the shape of the special vehicle itself is too wide and too high, and whether the cargo are too long, too wide or too high	0: in good condition; 1: size overran
	S13 Stability of vehicle cargo	Whether the vehicle and the cargo in its trailer are securely secured	0: in good condition; 1: the goods were unstable
	S14 Vehicle communication equipment	Whether the communication equipment equipped with the vehicle is in good condition	0: in good condition; 1: poor state
Airport road	S15 Geometric property	Including the road plane alignment, transverse and longitudinal section layout, visual distance assurance	0: in good condition; 1: poor state
	S16 Road crossing	Including road level intersections, parking entrances and exits	0: in good condition; 1: poor state
	S17 Pavement condition	Including flatness, snow and water on pavement, road collapse, etc.	0: in good condition; 1: poor state
	S18 Indicator marking line	Whether the road indication signs in the airport are clear and reasonable, and whether the road markings are clearly visible	0: in good condition; 1: poor state
Natural environment	S19 Weather	Rain, fog, snowstorms and other bad natural weather	0: negligible; 1: acceptable; 2: unacceptable
Transportation (artificial) environment	S20 Night lighting	Whether the night lighting facilities are good	0: in good condition; 1: poor state
	S21 FOD (Foreign Object Debris)	Presence of FOD in the carriageway	0: acceptable (normal road without fod); 1: unacceptable (fod on the road)
	S22 Driving environment	An environment composed of various road traffic participants such as motor vehicles, non-motor vehicles and pedestrians	0: acceptable; 1: unacceptable
	S23 Roadside environment	Various facilities and special equipment for aircraft maintenance and flight protection along the carriageway	0: acceptable; 1: unacceptable
Management	S24 Management of airport operation department	The management level of the airport operation management department	0: acceptable; 1: unacceptable
	S25 Supervise the setting of reward and punishment system	The supervision and punishment mechanism of the airport management department for violations of regulations	0: acceptable; 1: unacceptable
	S26 Integrity and implementation of safety education content	Whether the content of personnel safety training is complete and comprehensive, and whether it is in place	0: acceptable; 1: unacceptable

Table 1.

Road traffic safety risk assessment index system in the aircraft activity area of civil aviation airports.

No.	Natural language variable	Triangular fuzzy function (l_i, m_i, n_i)
1	Very low	(0, 0, 0.1)
2	Low	(0, 0.1, 0.3)
3	On the low side	(0.1, 0.3, 0.5)
4	Medium	(0.3, 0.5, 0.7)
5	High	(0.5, 0.7, 0.9)
6	On the high side	(0.7, 0.9, 1)
7	Very high	(0.9, 1, 1)

Table 2.

Correspondence between natural language variables and triangular fuzzy numbers.

State variable	S1	S2	S3	S4	S5	S6	S7	S8	S9	S10	S11	S12	S13
0	4.4%	92.2%	99.7%	99.0%	96.9%	98.6%	96.7%	99.9%	99.9%	93.7%	97.4%	93.8%	97.3%
1	93.4%	7.8%	0.3%	1.0%	3.1%	1.4%	3.3%	0.1%	0.1%	6.3%	2.6%	6.2%	2.7%
2	2.2%
State variable	S14	S15	S16	S17	S18	S19	S20	S21	S22	S23	S24	S25/S26
0	98.5%	97.3%	94.7%	98.0%	97.4%	76.0%	97.2%	99.4%	81.1%	98.0%	97.6%	97.9%
1	1.5%	2.7%	5.3%	2.0%	2.6%	21.3%	2.8%	0.6%	18.9%	2.0%	2.4%	2.1%
2						2.7%

Table 3.

Initial probability.

Aspect	Event	No.
Person
(a) Driver	Fatigue driving	X1
	Greater time pressure	X2
	Illegal operation of vehicle special equipment	X3
	Driving violations:
	(1) Overspeed	X4A
	(2) To maintain a safe distance	X4B
	(3) Illegal overtaking (or side-by-side)	X4C
	(4) Failure to stop at a stop line for observation	X4D
(b) Pedestrian	No reflective vest	X5
	Poor physical condition	X6
	Not following the prescribed route	X7
	Inadvertent entry by non-staff such as travellers	X9
Vehicle	Vehicles in substandard technical condition:
	(1) Steering failure	X10A
	(2) Brake failure	X10B
	(3) Tire burst	X10C
	(4) Parts aging	X10D
	Vehicles not fitted with reflective signs or warning lamps	X11
	Vehicle (including cargo) oversized length (width, height)	X12
	Vehicle load not properly secured	X13
	Vehicle communication equipment failed	X14
Road	Road curves too quickly	X15
	Failure to provide facilities at intersections to eliminate blind areas	X16
	Poor road condition: Slippery roads	X17
	Road signs were not clearly marked	X18
Environment	Low visibility weather	X19
	Poor lighting at night	X20
	FOD on the road	X21
	Complex roadside environment	X23
Management	Inadequate road design:
	(1) Poorly designed road alignment	X25A
	(2) Excessive intersections of carriageways with aircraft taxiways	X25B
Other	Incorrect command (when the tower directed the wrong vehicle to enter the runway)	X29
	Driver misinterpreted the commander's instructions	X30
	Staff members brought fire into the airport in violation of the law	X31
	Inadvertent fire while using fire	X32
	Vehicles not equipped with effective fire extinguishing equipment	X33
	Personnel did not use fire extinguishing equipments	X34
	Omitted event:
	(1) Traffic coming from behind could not attract the attention of pedestrians	Y1
	(2) Vehicles overtaking oncoming traffic on a borrowed lane	Y2
	(3) Vehicles passing taxiway intersections with aircraft taxiing	Y3
	(4) Air Traffic Control failed in its duty	Y4
	(5) The car in front suddenly slowed down	Y5

Table 4.

Basic cause events.

No.	Event
T	Person-vehicle accident
A1	Scenario 1
A2	Scenario 2
B1	Pedestrians failed to yield
B2	Driver did not notice the pedestrian
B3	Driver noticed the pedestrian braking, but the vehicle did not stop
C1	Poor pedestrian visibility
C2	Driver unsafe state 1
C3	Objective unsafe state
C4	Human insecurity 1
C5	Environment is unsafe
C6	Unsafe state of vehicle
D1	Unsafe state 1
D2	Unsafe state 2
D3	Blind areas exist at road junctions
D4	Large vehicles had visual blind areas
D5	Driver unsafe state 2
D6	Pedestrian burst out
E1	Human insecurity 2

Table 5.

Resulting events of the person-vehicle fault tree.

No.	Minimum cut set	Description
1	{X6, X5, X19}	In low visibility and bad weather, pedestrians without reflective vests were less noticeable to vehicle drivers, and those with poor physical condition reacted slowly and were unable to avoid vehicles.
2	{X6, X5, X20}	In poorly lit road environments at night, pedestrians without reflective vests were less noticeable to vehicle drivers, and those with poor physical condition reacted slowly and were unable to avoid vehicles.
3	{X6, X3}	Drivers illegally operated special on-board equipment, and pedestrians with poor physical condition reacted slowly and were unable to avoid vehicles.
4	{X6, X1}	Drivers drove fatigued, and pedestrians with poor physical condition reacted slowly and were unable to avoid vehicles.
5	{X6, X25A}	The road alignment was not reasonably designed, and there were blind areas at corners that made it difficult for drivers to spot pedestrians, and pedestrians in poor physical condition reacted slowly to avoid vehicles.
6	{X6, X12}	Vehicles were too large with blind areas, and pedestrians in poor physical condition reacted slowly to avoid vehicles.
7	{X6, 4A}	The driver was speeding and the pedestrian in poor physical condition reacted slowly to avoid vehicles.
8	{X6, X7}	Pedestrians failing to follow the prescribed route and pedestrians in poor physical condition with slow reaction time failing to yield to vehicles.
9	{X6, X9}	Passengers or other outsiders mistakenly entered the aircraft's area of operation and was in poor physical condition and slowed to avoid the vehicle.
10	{X6, X17A}	Slippery road surfaces and slow reaction time of pedestrians in poor physical condition to avoid vehicles.
11	{X6, X10B}	Vehicle brakes failed and pedestrians in poor physical condition reacted slowly to avoid the vehicle.
12	{Y1, X5, X19}	Vehicles approaching from behind pedestrians and pedestrians not wearing reflective vests were not easily detected by vehicle drivers in bad weather with low visibility.
13	{Y1, X5, X20}	Vehicles approaching from behind pedestrians and pedestrians not wearing reflective vests in poorly lit road environments at night were not easily detected by vehicle drivers.
14	{Y1, X3}	Vehicle approaching from behind pedestrians and driver's unauthorised operation of on-board special equipment.
15	{Y1, X1}	Vehicle approaching from behind pedestrians and driver fatigue.
16	{Y1, X25A}	The road design was not optimal, with blind areas at the bends that made it difficult for the driver to spot the pedestrian. As the vehicle was behind the pedestrian, they couldn't detect and avoid it in time.
17	{Y1, X12}	Vehicles approaching from behind pedestrians with blind areas due to the size of the vehicle.
18	{Y1, 4A}	Vehicle approaching from behind pedestrians and driver speeding.
19	{Y1, X7}	Pedestrian deviated from the prescribed route, and as the vehicle was behind them, they couldn't identify and avoid it on time.
20	{Y1, X9}	There were accidental entries of an outside people, and with a vehicle approaching from behind the pedestrians, they couldn't detect and avoid it in time.
21	{Y1, X17A}	Slippery road surface and vehicles behind pedestrians, pedestrians were unable to spot and avoid vehicles in time.
22	{Y1, X10B}	Vehicle brakes fail and vehicles behind pedestrians, pedestrians were unable to spot and avoid vehicles in time.

Table 6.

Minimum cut set of person-vehicle fault tree.

Importance ranking	Basic cause event
1	X6, Y1
2	X1, X3, X4A, X7, X9, X10B, X12, X17, X25A
3	X5
4	X19, X20

Table 7.

Ranking of importance of basic event structure in person-vehicle fault tree model.

No.	Minimal cut set	Cut set probability (per million)	Top event probability (per million)	Accident pattern description
1	{X6, X5, X19}	12	2,558	Traffic accidents involving pedestrians who failed to yield to vehicles due to their physiological condition when vehicles were approaching them
2	{X6, X5, X20}	12
3	{X6, X3}	42
4	{X6, X1}	308
5	{X6, X25A}	378
6	{X6, X12}	868
7	{X6, 4A}	3
8	{X6, X7}	462
9	{X6, X9}	14
10	{X6, X17A}	280
11	{X6, X10B}	182

Table 8.

Probability calculation value of person-vehicle fault tree.

Theoretical model calculation and analysis		The important hazard sources were identified by accident causation analysis	Formulate security management countermeasures
Bayesian Network Model	Pedestrian traffic characteristics	Under the influence of inclement natural weather, it could lead to pedestrians have poor visibility and do not follow prescribed routes, poor vehicle recognition and slippery roads.	(1)
Bayesian Network Model	Driver traffic characteristics	Driver fatigue, high time pressures	(2)
Fault Tree Model	Quantitative calculation results	Driver fatigue, high time pressures	(2)
		Complex roadside environment	(3)(4)
		Special vehicles have visual blind areas.	(5)
	Qualitative analysis of person-vehicle fault tree	Special vehicles have visual blind areas.	(5)
		The driver illegally operated special equipment, speeding.	(6)
		Pedestrians not wearing reflective undershirts and not following the prescribed route.	(6)
		Passengers mistakenly entering the aircraft activity area.	(7)
		Blind areas at intersections.	(8)

Table 9.

Security management countermeasures.