IDENTIFICATION OF UNDESIRABLE EVENTS
IN THE MUNICIPAL TRANSPORT SYSTEM
IDENTYFIKACJA ZDARZEŃ NIEPOŻĄDANYCH
W SYSTEMIE TRANSPORTU MIEJSKIEGO
Maciej Woropay, Piotr Bojar, Klaudiusz MigawaUniversity of Technology and Live Science Bydgoszcz
Abstract: Road transport systems are socio-technical systems of the type Human – Technical object- Environment <H-TO-E>. In these systems hazards can be caused by: the human H, the technical object TO , and influence of the environment on the technical object and people who are present in the system and its environment. The authors of the paper make an attempt to evaluate the level of threats resulting from intended or not intended actions of people situated in this environment.
Key words: safety, undesirable events
Streszczenie: Systemy transportu drogowego są systemami socjotechnicznymi typu
Człowiek – Obiekt Techniczny – Otoczenie <C – OT – O>. W systemach tych zagrożenia mogą być stwarzane przez: człowieka C, obiekt techniczny OT oraz przez oddziaływanie otoczenia O na obiekt techniczny i ludzi znajdujących się w systemie oraz w jego otoczeniu. W pracy podjęto próbę oceny poziomu zagrożeń wynikających z zamierzonych lub niezamierzonych działań ludzi usytuowanych systemach transportu drogowego oraz ich otoczeniu.
1. Introduction
Municipal transport systems are such systems whose aim is to carry out transport tasks over an assigned area, with the use of transport means. The main requirements that must be met by such systems are:
- transport safety,
- transport means reliability, - transport punctuality,
- proper frequency of carried out transports, - proper standard of offered services.
The operation area of the municipal transport also includes suburbs which are beyond the administrative borders of the city though performing similar functions as town districts. The most popular kind of municipal transport is bus transport due to the fact that it does not require additional tracts or railroads, moreover, this kind of transportation provides a possibility of changing routes along which these transport tasks are accomplished. These systems are examples of socio-technical systems of the type Human-Technical Object-Environment – H-TO-E, in which accomplishment of transport tasks is the direct responsibility of an executive subsystem consisting of elementary subsystems of the type – human – technical object (operator –transport means) carrying out tasks in the system surroundings. Due to presence of people in the system, the most significant criterion for assessment of the accomplished transport tasks is their operation safety. Action is a notion referring to the human, action means human behavior (external and internal act, its omission or suppression) if the one who acts or many who act, associate some subjective sense with it. According to the author of paper [4] there are four kinds of actions:
action rational in terms of the goal, when the acting individuals are motivated by instrumental rationality: the subject chooses goals from a set of values and matches appropriate means taking into consideration alternative costs and benefits
action rational in terms of values, in contrast to the above, the acting individuals are not motivated by calculation of the action consequences ( according to the rule ‘the end justifies the means’) affectionate action, corresponding to current emotional states, traditional action, basing on habitual behavior
In work (Watusiński, 1980), technical actions have been defined as oriented to achieving a goal. set by the man. Technical action requires previous intellectual preparation, not always immediately specified. Functioning,
however, is a notion which refers to machines (technical objects). Analyzing socio-technical systems H-TO-E, it can be said that these systems operate thanks to the role people play in them. Operation safety of a municipal bus transport system is its state for which values of identified features, describing the system in a fixed time t, [t , t], remain within established boundaries with defined levels of the impact of forcing factors. These factors can be divided into (Woropay, et. al., 2008; Szpytko and Kocerba, 2008):
operational - forcing factors which affect the transport means in result of performing useful functions
external – forcing factors characterizing the impact of the environment on the transport means ( not conditioned by its functioning)
antropotechnical -forcing factors affecting the transport means in result of human actions, eg the operator’ mistakes
A negative impact of these factors is the cause of occurrence of undesirable events in transport systems.
2. The Research Object
The research object is a bus transport system in a big urban agglomeration, which is a socio-technical system of the type Human- Technical Object – Environment <H-TO-E> whose main task is safe transport of a given number of people over an assigned area with the use of transport means utilized in this system.
3. The Research Goal
Providing the municipal bus transport, being the whole of means and actions connected with transport of people, with high level of safety is a key problem due to vast numbers of people carried by transport means, high intensity of traffic, and poor infrastructure of roads along which the transport tasks are performed.
For this reason, the authors have assumed an identification of events undesirable in the municipal bus transport system, as the research goal. This provides the basis for taking rational actions aiming at reduction of the number of these events and minimization of their negative effects.
4. Identification of Undesirable Events
An event is a change or duration of a state in moment (Woropay and Muślewski, 2005). In this work an undesirable event has been defined as an
event which leads to occurrence of material damages or injuries of people who are present in the system or in its environment.
For his reason, there has been made a classification of possible undesirable events, on the basis of the following criteria:
- kind of the event - place of the event - cause of the event
Figure 1 presents classification of undesirable events according to their kinds. There can be distinguished the following events:
Road collision – an event which caused only material damages.
Road accident – an event occurred within a road space in result of which at least one person was dead or sustained injuries..
Vehicle devastation - conscious behavior of people (passengers) aiming at damaging the vehicle.
Damage to the vehicle – exceeding admissible boundary values by features describing the vehicle, causing change of its state from the usability state to the limited usability state or unfitness for use.
UNDESIRABLE EVENTS
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Fig.1 Classification of undesirable events
On the basis of experimental tests carried out within the bus transport system, in a big urban agglomeration, the percentage of particular events in the set of all the undesirable events, was established as well as the percentage of undesirable events in the set of all occurred events according to the place of their occurrence; results of experimental tests have been presented in fig. 2 and 4.
Fig.2 Percentage of particular events in the set of all occurred undesirable events
In figure 3 Classification of undesirable events according to the place of their occurrence, place of undesirable event occurrence
PLACE OF UNDESIRABLE
EVENTOCCURENCE
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Fig.3 Classification of undesirable events according to the place of their occurrence
Fig 4 Percentage share of undesirable events in the set of all events according to the place of occurrence
The next classification of undesirable events is a classification according to the causes of undesirable events occurrence.
Having made a detailed analysis of causes of a road event occurrence, each of the forcing factors can be divided into an array of undesirable factors accounting for causes of these events occurrences. A detailed classification of causes has been presented in figure 5.
Analyzing a road event and the cause of its occurrence it is necessary to consider primary criteria of the event occurrence ( the main cause), and then second – rate criterion (criteria). Then, providing the assessment criteria of operation safety, it is possible to see the cause of the analyzed undesirable event occurrence. A precise identification of undesirable events occurrence causes, is a basis for elaboration of the system operation safety state diagnosis algorithm.
CAUSES OF UNDESIRABLE ROAD EVENTS OCCURRENCE
Limited usability state Inappropriate actions of people Negative impact of the environment
d am ag e to i n si g n if ic an t su b sy st em s d am ag e to s u b sy st em s o f le ss i m p o rt an ce d am ag e to s ig n if ic an t su b sy st em s d am ag e to c ri ti ca l su b sy st em s Inside the vehicle In the vehicle surroundings In the subsystem servicing the vehicle
In ap p ro p ri at e b eh av io r o f th e d ri v er In ap p ro p ri at e b eh av io r o f th e v eh ic le p as se n g er In ap p ro p ri at e b eh av io r o f p eo p le wa it in g a t th e b u s st o p In ap p ro p ri at e b eh av io r o f o th er t ra ff ic p ar ti ci p an ts In ap p ro p ri at e ac ti o n s o f d ia g n o st ic ia n s In ap p ro p ri at e ac ti o n s o f m ec h an ic s Ne g at iv e im p ac t o f we at h er c o n d it io n s P o o r st at e o f th e ro ad s u rf ac e Im p ro p er ly d es ig n ed r o ad i n fr as tr u ct u re
Fig.5 Classification of causes of undesirable events occurrence
5. Assessment Algorithm of a Municipal Road Transport System Operation Safety
The algorithm presented in figure 5 reflects the procedure for the process of a road transport system operation safety assessment, taking into consideration the impact of primary forcing factors whose impact sequences have been presented in table 2.
In this algorithm there can be identified three basic members being constituent algorithms: A,B,C applying successively to:
algorithm A – concerning the transport means operation safety,
algorithm B – concerning assessment of the system environment impact on its operation safety,
algorithm C – concerning assessment of the impact of people present in the system and its environment on the system operation safety.
Particular component algorithms A, B and C determine an overall way of the transport system operation safety assessment. Table 3 shows a description of particular blocks of the algorithm.
A B C 1 A1 5 4 3 2 A9 A8 A7 A6 A5 A4 A3 A2 7 6 A12 A11 A10 B4 B31 B21 B11 B3 B2 B1 B9 B8 B7 B6 B5 B10 C6 C5 C31 C21 C11 C3 C2 C1 C8 C7 C10 C9 STOP START TAK TAK TAK TAK TAK TAK TAK TAK NIE TAK NIE TAK NIE TAK NIE TAK NIE TAK NIE TAK NIE TAK NIE NIE NIE NIE NIE TAK NIE TAK NIE TAK NIE TAK TAK NIE TAK NIE NIE NIE NIE NIE C4 C41 C42 C411 C421 TAK NIE NIE NIE NIE NIE TAK TAK NIE NIE TAK TAK
Table3. Description of general blocks of the transport system operation safety.
The block
code
The code description
1 Determine a set of road events occurred in the analyzed time period Zi;i={1,2,4….,k}.
2 Choose an event significant from the point of view of the analyzed system operation safety.
3 Rank events according to the date of occurrence Z , Z , Z ….Z. 4 Choose for assessment the first event Z i=1
5 Choose for assessment the successive road event Z + 1
A Was a damage to the transport means subsystem the cause of a road event?
A1 Establish criteria for assessment of the damage significance A2 Make an assessment of the damaged subsystem.
A3 Is the damaged subsystem significant in terms of the transport system operation safety?
A4 Had the damage to a significant subsystem an impact on incorrect behavior of the operator?
A5 Evaluate the level of transport means usability state changes as the effect of the analyzed subsystem damage.
A6 Make collective evaluation of the transport system operation safety A7 Evaluate the costs due to the events occurred
A8 Determine the transport means operation safety assessment criteria A9 Establish the transport means operation safety assessment criteria A10 Has the analyzed event Z=Z where i={1,2,3,…k}
A11 Is the resultant model adequate? A12 Check if B event occurred as well?
B Was the impact of the environment a cause of the analyzed event occurrence?
B1 Was the road poor surface the cause of the analyzed event occurrence? B11 Was the road poor surface the cause of a damage to the transport
means?
B2 Was a poor road infrastructure the cause of the road event occurrence? B21 Was the road poor infrastructure the cause of the transport means
damage?
B3 Was the impact of weather conditions the cause of the road event occurrence?
B31 Was the impact of weather conditions the cause of inappropriate actions of people present in the system and its surroundings?
Table 4 Description of general blocks of the transport system operation safety asessment algorithm.
The block
code
The code description
B4 Determine a set of indexes for assessment of the environment safe impact on people and transport means?
B5 Establish criteria for assessment of safe impact of the environment on people and transport means?
B6 Determine a set of representative indexes for assessment of safe impact of the environment on people and transport means>
B7 Make an assessment of the environment safe impact on people and transport means.
B8 Does the analyzed event Z = Z ? where i={1,2,3,….,k} B9 Is the resultant model adequate?
B10 Check if C event occurred, as well?
C Was the impact of the people present in the transport means and its environment the cause of the analyzed event?
C1 Was inappropriate behavior of the driver the cause of a road event? C11 Was inappropriate behavior of the driver the cause of the transport
means subsystem damage?
C2 Was inappropriate behavior of transport means
C21 Did inappropriate behaviors of passengers provoke the driver’s incorrect actions?
C3 Did inappropriate behaviors of people present in the transport system environment contribute to the road event occurrence?
C31 Did inappropriate behaviors of people present in the transport means environment provoke the driver’s incorrect actions?
C4 Were inappropriate behaviors of people present in the subsystem responsible for ensuring usability the cause of the event occurrence? C41 Were inappropriate actions of diagnostics the cause of the road event? C411 Were inappropriate actions of diagnostics the cause of the driver’s
incorrect behavior?
C42 Were inappropriate actions of mechanics the cause of the event occurrence?
C421 Were inappropriate actions of mechanics the cause of the driver’s wrong behavior?
C5 Determine a set of indexes for an assessment of undesirable impact of people present in the transport system and its environment.
C6 Establish criteria for an assessment of a safe impact of people present in the transport system and its environment.
Table 4 Description of general blocks of the transport system operation safety asessment algorithm.
C7 Choose a set of representative indexes for an assessment of the impact of people present in the transport system and its environment.
C8 Make an assessment of safe impact of people present in the transport system and its environment.
C9 Is the analyzed event Zi=Zk where i={1,2,….,k} C10 Is the resultant model adequate?
6 Make a summary assessment of the transport means operation safety. 7 Show the result
The next step of the transport system operation safety assessment is determination of a criterion for the system safe operation. For this purpose it is necessary to determine a set of measurable features X (i=1,2,…,n) and a set of significant non-measurable features X (j=1,2,…,m), describing the system in terms of its operation safety. Next, it is necessary to determine, for each of measurable features, admissible boundaries
X
Mmin,i andX
Mmax,icorresponding to the system safe operation (safe accomplishment of a transport task).
And similarly, it is necessary to set, for each of non –measurable features, criteria enabling to establish correctly whether a given feature corresponds to conditions of safe operation of the system. Such a state can be symbolically recorded X =1, whereas, the opposite case X =0. Then, the condition of the System Safe Operation in a given time t,t [t t] can be presented in the following way:
1 ,..., 1 ,..., , , , 1 , max , , , min , max 1 , , 1 , min 1 , t m N t N n M t n M n M M t M M X X X X X X X X BDS (3) 6. Conclusions
The method of making the transport system operation safety analysis, proposed in this paper, is an innovative approach to an assessment of road transport systems operation safety.
This method is of universal character and can find application for assessment of different types of transport systems.
The algorithm components can be separate methods of an assessment of the impact of particular forcing factors on the analyzed system operation safety level.
There is a need to make a further analysis of the p considered problem in order to demonstrate all the existing reactions between particular elements of the analyzed system.
7. References
[1]. Woropay M., Muślewski Ł.: Jakość w ujęciu systemowym. Wydawnictwo Instytutu Technologii Eksploatacji. Bydgoszcz – Radom 2005
[2]. Weber M.: Wirtschaft und Gesellschaft. Wydawnictwo Naukowe PWN Warszawa 2002
[3]. Woropay M., Wdzięczny A., Bojar P., Szubartowski M.: Metoda oceny wpływu skuteczności realizowanych napraw na niezawodność i bezpieczeństwo działania systemów transportu drogowego. Wydawnictwo Naukowe Instytutu Technologii. Bydgoszcz-Radom 2008
[4]. Szpytko J., Kocerba A.: Wybrane aspekty bezpieczeństwa i niezawodności rozproszonych środków transportu. Wydawnictwo Instytutu Technologii Eksploatacji w Radomiu. Kraków – Radom 2008.
[5]. Watusiński Z.: Metody techniki. Projektowanie i systemy – tom II. Zagadnienia metodologiczne. Zaklad Narodowy imienia Ossolińskich. Wydawnictwo Polskiej Akademii Nauk. Wrocław 1980
Professor Maciej Woropay is the head of the Machine Maintenance Department at the Mechanical Engineering Faculty of the University of Technology and Life Sciences in Bydgoszcz. In his research he deals with problems connected with theory of systems, theory of reliability and safety, and maintenance process control in complex biotechnical systems, especially with control of these processes in real transport systems. He is the author and co-author of over 140 scientific papers published in Poland and abroad, as well as textbooks and academic scripts; he has been a promoter of 150 Master’s and Bachelor’s theses and doctoral theses.
Ph.D eng. Piotr Bojar is work in Transport Department at the Mechanical Engineering Faculty of the University of Technology and Life Sciences in Bydgoszcz. In his research he deals with analysis and assessment of operational safety of real means of road transport. Author and co-author of several scientific papers on road transport safety and reliability of technical objects.
Ph.D eng. Klaudiusz Migawa is the adjunct in the Machine Maintenance Department at the Mechanical Engineering Faculty of the University of Technology and Life Sciences in Bydgoszcz. In his research he deals with problems relating to modelling processes and the systems of exploitation and steering the processes of exploitation in folded systems. He guides investigations relating to the questions of the opinion and formation of readiness and the reliability of the systems of the exploitation of the means of municipal transportation.
