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Evaluating gravel transport sustainability: A case study of Taiwan’s northeast corridor
Transportation Research Part D 17 (2012) 287–292
Contents lists available at SciVerse ScienceDirect
Transportation Research Part D journal homepage: www.elsevier.com/locate/trd
Evaluating gravel transport sustainability: A case study of Taiwan’s northeast corridor Tzay-An Shiau ⇑, Yi-Ru Chuang National Taiwan Ocean University, Keelung, Taiwan
a r t i c l e
i n f o
Keywords: Gravel transportation Intermodal transportation Social-eco-efficiency Environmental effects of gravel movement
a b s t r a c t We use social-eco-efficient analysis in the form of SEEbalance to evaluate gravel transport sustainability for trucking and two kinds of intermodal transportation. Results show that switching from trucks to intermodal transportation can improve the sustainability of gravel transportation in the northeast corridor of Taiwan. Sensitivity analysis shows that rail combined with truck intermodal transportation has competitive advantage despite the terminal’s location factor. Ó 2012 Elsevier Ltd. All rights reserved.
1. Introduction Trucking is one of the main gravel transportation modes along the northeast corridor of Taiwan, primary due to the advantage of door-to-door service. Heavy trucks, however, damage pavement, disturb environmentally and ecologically sensitive areas, and cause fatal traffic accidents. Intermodal freight transportation is a competitive means of transport, and can be environmentally friendly than truck transportation.1 Most studies have investigated the advantages of intermodal freight transportation in reducing cost and environmental impacts with traffic accidents and the social effects of industrial structure impacts attract less attention. Here we use SEEbalance (social-eco-efficient), an integrated tool, to evaluate gravel transport alternatives in the northeast corridor of Taiwan to gain broader insights. 2. Research method Gravel is a raw material, and its transportation is part of the overall supply-chain in its use in construction engineering. We assume that modal shifting does not change the methods or locations of gravel product, use, recycling, and waste recovering, but look at the implications of using various modes for transporting it. We consider the alternative transport options from cradle to gate within gravel’s life cycle in construction engineering using the SEEbalance method (Saling et al., 2005; Kölsch et al., 2008) adjusted slightly to accommodate the local characteristics of Taiwan. The evaluation procedure can be summarized as: Initial we define customer benefits from gravel transportation from eastern Taiwan to northern Taiwan, comparing; truck-only, truck combined with rail, and truck combined with water transportation. ⇑ Corresponding author. Tel.: +886 02 2 28051649; mobile: +886 933991816; fax: +886 2 28051647. E-mail addresses: [email protected], [email protected] (T.-A. Shiau). Liao et al. (2009), for example, compared CO2 emissions from truck-only and intermodal coastal shipping and truck movements for containers and found the latter can significantly reduce CO2 emissions. Patterson et al. (2008) examined the potential for reducing CO2 emissions in the Quebec city – Windsor corridor and found that intermodal transportation can reduce them by 50% when compared to truck-only transportation. 1
1361-9209/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.trd.2012.01.003
288
T.-A. Shiau, Y.-R. Chuang / Transportation Research Part D 17 (2012) 287–292
We create indicators for evaluating sustainability by considering economic, environmental, and societal aspects of the alternative modes. The economic aspect consists of indicators that describe the generalized costs from a customer’s viewpoint and includes transportation cost, transit time from origin to destination, traffic accident cost, and terminal operation cost. The environmental aspect consists of resource consumption, energy consumption, CO2 emissions, and toxic matter that adversely affections air and water quality. The social aspect consists of labor management, quality of life, damage caused by industrial operations, employee’s welfare and equity, and business development. Labor management consists of research and development, labor inputs, strikes and suspensions, and inputs for professional training. The damage caused by industrial operations is expressed in the number of fatalities, property damage, and production damage, with employee’s welfare and equity measured in terms of the percentage of disabled persons hired, family security, and the percentage of professional employees. Business development represents domestic and foreign investment, and imports from developing countries. Fig. 1 shows the hierarchical framework of these indicators. To construct the weighting scheme we use the analytic hierarchy process (AHP) (Saaty, 1980), allowing analyze of societal weights according to the hierarchical structure of measurable indicators (Fig. 1). For AHP applications, users first establish priorities among the elements of the hierarchy by constructing a series of pair-wise comparison matrices for the elements. Subsequently, the overall priorities for the hierarchy are determined by applying a linear additive decomposition principle. The consistency of the judgment is verified to ensure stable preferences. To measure and normalize performance indicators we use the performance of three kinds of transport based on doorto-door attributes. Truck-only transportation involves door-to-door service, while intermodal transportation must also consider line-haul and feeder transportation. A normalization process is used to allow meaningful aggregation of indicators.
Gravel transport sustainability
Society
Ecology
Efficiency
Terminal operation cost
Traffic accident cost
Transit time between O-D
Transportation cost
Toxicity potentials
CO 2 emissions
Energy consumption
Resources consumption
Business development
Employee welfare and equity
Damage caused by industrial operation
Quality of life
Labor management
Air pollutants
Water pollutants
Imports from developing countries
Capital investment
Foreign investment
Family security
The percentage of professional employees
The percentage of disabled persons hired
Property damage
Production damage
Number of fatalities
Inputs for professional training
Labor inputs
Strikes and suspensions
Research and development
Fig. 1. Gravel transport sustainability indicators.
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T.-A. Shiau, Y.-R. Chuang / Transportation Research Part D 17 (2012) 287–292
Keelung port ; Taipei port
Hualian port Water transport Ship Highway transport
Highway transport Truck
Truck
Highway transport Truck
Truck
Truck
Highway transport
Highway transport
Rail transport Train Wu-Du station
Shing-Cheng station Legend
Singer supply node Multiple demand nodes
Two ports in destination Train station
Single port in origin Line-haul transport
Feeder transport Fig. 2. Gravel transportation options in Taiwan’s northeast corridor.
A weighting scheme aggregates the normalized indicator performance values into economic, environmental, and societal aspects. Subsequently, three aspects are aggregated to calculate gravel transport sustainability. Fig. 2 shows the gravel transportation network in the northeast corridor of Taiwan. Eastern Taiwan is rich in gravel resources and acts a supplier to the rest of the country while northern Taiwan is a highly urbanized region that demanding a considerable amount of gravel for construction. Water transportation starts at Hualian port and ends at Keelung port or Taipei port; unlike Taipei Keelung port does not allow warehousing for gravel because of its limited inland area. Railway transport starts at Shing–Cheng station and ends at Wu–Du station; both stations having land available for gravel warehousing. 3. Results The Taipei metropolitan area in northern Taiwan has a population of over six million and we assess the implications of gravel transport to it from Hualian. Wu–Du station and Keelung port are located to the east of the Taipei metropolitan area, while Taipei port is on the western side. We assess gravel transport sustainability by considering destination nodes locating on the eastern side of the Taipei metropolitan area, while Keelung port is selected as the destination port (Fig. 2). We recruited 57 experts from the transportation research community and elicited their views on social weights. The questionnaire went to 19 individuals with social backgrounds, 19 with economic backgrounds, and 19 with environmental backgrounds. The experts are all concerned with gravel transportation along the northeast corridor. Only 18 usable replies were obtained, in part because of the complex pair-wise comparison procedure required when applying the AHP. These comprise five with social, seven with economic, and six with environmental interests. The two-stage geometric average from their responses was calculated and normalized to represent compromised societal weights (Table 1). During the first-stage, the geometric average is calculated based on individual professional background; a process iterated three times. During the second, the geometric average compromises the weights of three professional backgrounds. The final compromise weights are independent from unequal distributed representatives. Table 1 shows relatively consistent weights between societal, environmental, and economic aspects. The experts also recognized the following important indicators with weights
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T.-A. Shiau, Y.-R. Chuang / Transportation Research Part D 17 (2012) 287–292
Table 1 Criteria weights for gravel transport sustainability assessment. Society: 0.300
Labor management: 0.051
Research and development: 0.011 Labor inputs: 0.013 Strikes and suspensions: 0.013 Inputs for professional training: 0.014
Quality of life: 0.072 Damages caused by industrial operation: 0.072
Employee’ welfare and equity: 0.051
Business development: 0.054
Environment: 0.370
Resource consumption: 0.089 Energy consumption: 0.089 Toxicity potentials: 0.092
Number of fatalities: 0.032 Property damage: 0.020 Production damage: 0.020 Percentage of disabled persons hired: 0.014 Family security: 0.017 Percentage of professional employees: 0.020 Capital investments: 0.019 Foreign investments: 0.017 Imports from developing countries: 0.018
Air pollutants: 0.050 Water pollutants: 0.042
CO2 emissions: 0.100 Economy: 0.330
Transportation cost: 0.086 Transit time between O–D: 0.076 Traffic accident cost: 0.102 Terminal operation cost: 0.066
Table 2 Normalized performance of economic aspect for gravel transportation. Indicator
Mode
Transportation cost (TWD/T) Transit time between O–D (Minutes) Traffic accident cost (TWD/T) Terminal operation cost (TWD/T)
Truck-only
Rail combined with truck
Ship combined with truck
1.00 0.33 1.00 0.57
0.68 0.38 0.08 0.76
0.52 1.00 0.16 1.00
(490) (330) (234) (79)
(335) (385) (18) (105)
(254) (1015) (38) (138)
Notes: The parenthesis indicates the original performance.
Table 3 Normalized performance of environmental aspect for gravel transportation. Indicator
Resource consumption Energy consumption CO2 emissions Toxicity potentials
Mode Truck-only
Rail combined with truck
Ship combined with truck
1.00 1.00 1.00 1.00
0.18 0.53 0.35 0.80
0.86 0.73 0.71 0.83
Table 4 Normalized performance of social aspect for gravel transportation. Indicator
Labor management Quality of life Damages caused by industrial operation Employee’ welfare and equity Business development
Mode Truck-only
Rail combined with truck
Ship combined with truck
0.69 0.63 1.00 1.00 0.42
1.00 1.00 0.31 1.00 0.12
0.80 0.24 0.25 1.00 1.00
exceeding 0.080; resource consumption, energy consumption, CO2 emissions, toxicity potentials, transportation cost, and traffic accident cost. In terms of the impacts of various gravel transport options, Table 2 illustrates their performance in economic terms. Truck-only transportation has the advantages of door-to-door service and shortest transit times between O–D compared to intermodal alternatives; ship in conjunction with truck has the longest transit time between O–D. Other indicators, including transportation cost, traffic accident cost, and terminal operation cost were measured on a monetary basis.
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T.-A. Shiau, Y.-R. Chuang / Transportation Research Part D 17 (2012) 287–292 Table 5 Gravel transport sustainability measurement. Aspect
Efficiency Ecology Society Total
Mode Truck-only
Rail combined with truck
Ship combined with truck
0.33 (1.42) 0.34 (1.26) 0.23 (1.10) 0.90
0.19 (0.81) 0.20 (0.71) 0.20 (1.00) 0.59
0.18 (0.76) 0.30 (1.09) 0.18 (0.88) 0.66
Notes: The parenthesis indicates the value calculated by SEEcube basis.
Our results show that truck-only transportation is more expensive then intermodal transportation; ship combined with truck intermodal transportation being the cheapest. A trade-off between transportation cost and transit time is seen for all modes. To eliminate the effects of measurement units, the performance of each transportation mode was normalized using;
Eij ¼ Pij =ðMax Pij ; 8 iÞ
ð1Þ
where Pij is the performance of mode j measured by criteria i; Eij is the normalized value of Pij. The value of Eij indicates that less is preferable. Table 3 shows the normalized performance in terms of environmental impacts. Energy consumption for transportation and terminal use are included, with electricity consumption translated into primary energy usage and based on the power generation mix. In this context, truck-only transportation is the worst performer, and rail in conjunction with truck intermodal transportation best. Resource consumption and CO2 emissions are estimated based on energy consumption and its related transformation factors. The performance rankings in these items are identical to energy consumption. The environmental aspect also includes air pollutants HC, CO, NOx, and SOx, and estimates water contaminants, COD, BOD, SS, SO2 4 , and HC. We use a scoring system based on effluent standards established by Taiwan’s Environmental Protection Administration, and normalize the results (Table 3). We finds that truck-only transportation performs worst in terms of these toxic pollutants with railroad in conjunction with truck the best. Using Eq. (1) to measures and normalizes social aspects (Table 4), the three modal options performance equally in terms of employee’s welfare and equity. Truck-only transportation performs the best in labor management but the worst in terms of damage caused by industrial operation. Rail in conjunction with truck transportation performs the best in business development, and the worst in labor management and quality of life. Ship combined with truck is the best performer regarding quality of life and damages caused by industrial operation, and the worst in business development. Multiplying the societal weights (Table 1) by the normalized performance values (Tables 2–4) yields the weighted normalized performances of the three gravel transportation modes (Table 5). The weighted normalized performances of the three aspects is also adjusted based on the SEEcube references (the average of the weighted normalized performances is set to unity). Table 5 shows that truck-only transportation performs the worst in terms of our sustainability measure with rail combined with truck the best. Ship associated with has benefits in terms of both economic and social features. In terms of the intermodal options, on social-efficient criteria, ship combined with truck performs better than rail in conjunction with truck, but overall, rail combined with truck is the best mode with respect to transport sustainability. Interviews with management of a gravel company that moves large amounts of gravel from Hualian to the eastern side of the Taipei metropolitan area finds it uses rail in conjunction with truck because: It was as authorized to construct a warehouse at Wu–Du station, and the land rent is reasonable. Compared to truck-only transportation, the costs including transportation and warehousing are attractive. Even though rail combined with truck requires more transit time than truck-only transportation, a pre-scheduled plan can help respond to demand uncertainty. The warehouse at Wu–Du station is a used as buffer to balance supply and demand. Moreover, Wu–Du station is close to the final market, and this effectively reduces demand uncertainty. We apply sensitivity analysis to obtain additional information regarding Taipei port as the destination port (Fig. 2). While in this particular case, the sustainability ranking for the three transportation modes is the same as in Table 5, the score for rail combined with truck is closer to ship combined with truck. Sensitivity analysis, further shows that ship and truck intermodal transportation has an advantage for some areas of demand close to the port at Taipei. For traffic movements when the destination nodes involves Wu–Du station and Keelung port and are located on the eastern side of Taipei metropolitan area, our sensitivity analysis shows that rail combined with truck is the most competitive mode in terms of sustainability. When the destination node involving Taipei port are located on the western side of the Taipei metropolitan area, with Wu–Du station located on the eastern side, rail in conjunction with truck has a competitive advantage despite the terminal’s location.
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4. Conclusions Gravel movements in the northeast corridor of Taiwan currently depend heavily on highway transportation, but heavy trucks damage pavements, disturb frail geology, and can cause serious traffic accidents. The results of our SEEbalanace analysis support shifting to alternative intermodal transportation options; although truck-only transportation has the advantages of door-to-door service and the shortest transit times between O–D performs it performs less well in terms of overall sustainability compared to alternative intermodal transportation. Rail in conjunction with truck improves transport sustainability the most. Ship in conjunction with truck intermodal transportation performs almost the same as rail combined with truck when the destination node is located on the western side of the Taipei metropolitan area. References Kölsch, D., Saling, P., Kicherer, A., Grosse-Sommer, A., Schmidt, I., 2008. How to measure social impacts? A socio-eco-efficiency analysis by the SEEBALANCE method. Int. J. Sustain. Dev. 11, 1–23. Liao, C.-H., Tseng, P.-H., Lu, C.-S., 2009. Comparing carbon dioxide emissions of trucking and intermodal container transport in Taiwan. Transp. Res. D 14, 493–496. Patterson, Z., Ewing, G.O., Haider, M., 2008. The potential for premium-intermodal services to reduce freight CO2 emissions in the Quebec City–Windsor Corridor. Transport. Res. D 13, 1–9. Saaty, T.L., 1980. The Analytic Hierarchy Process. McGraw-Hill, New York. Saling, P., Maisch, R., Silvani, M., König, N., 2005. Assessing the environmental-hazard potential for life cycle assessment, eco-efficiency and SEEbalance. Int. J. Life Cycle Assess. 10, 364–371.
Contents lists available at SciVerse ScienceDirect
Transportation Research Part D journal homepage: www.elsevier.com/locate/trd
Evaluating gravel transport sustainability: A case study of Taiwan’s northeast corridor Tzay-An Shiau ⇑, Yi-Ru Chuang National Taiwan Ocean University, Keelung, Taiwan
a r t i c l e
i n f o
Keywords: Gravel transportation Intermodal transportation Social-eco-efficiency Environmental effects of gravel movement
a b s t r a c t We use social-eco-efficient analysis in the form of SEEbalance to evaluate gravel transport sustainability for trucking and two kinds of intermodal transportation. Results show that switching from trucks to intermodal transportation can improve the sustainability of gravel transportation in the northeast corridor of Taiwan. Sensitivity analysis shows that rail combined with truck intermodal transportation has competitive advantage despite the terminal’s location factor. Ó 2012 Elsevier Ltd. All rights reserved.
1. Introduction Trucking is one of the main gravel transportation modes along the northeast corridor of Taiwan, primary due to the advantage of door-to-door service. Heavy trucks, however, damage pavement, disturb environmentally and ecologically sensitive areas, and cause fatal traffic accidents. Intermodal freight transportation is a competitive means of transport, and can be environmentally friendly than truck transportation.1 Most studies have investigated the advantages of intermodal freight transportation in reducing cost and environmental impacts with traffic accidents and the social effects of industrial structure impacts attract less attention. Here we use SEEbalance (social-eco-efficient), an integrated tool, to evaluate gravel transport alternatives in the northeast corridor of Taiwan to gain broader insights. 2. Research method Gravel is a raw material, and its transportation is part of the overall supply-chain in its use in construction engineering. We assume that modal shifting does not change the methods or locations of gravel product, use, recycling, and waste recovering, but look at the implications of using various modes for transporting it. We consider the alternative transport options from cradle to gate within gravel’s life cycle in construction engineering using the SEEbalance method (Saling et al., 2005; Kölsch et al., 2008) adjusted slightly to accommodate the local characteristics of Taiwan. The evaluation procedure can be summarized as: Initial we define customer benefits from gravel transportation from eastern Taiwan to northern Taiwan, comparing; truck-only, truck combined with rail, and truck combined with water transportation. ⇑ Corresponding author. Tel.: +886 02 2 28051649; mobile: +886 933991816; fax: +886 2 28051647. E-mail addresses: [email protected], [email protected] (T.-A. Shiau). Liao et al. (2009), for example, compared CO2 emissions from truck-only and intermodal coastal shipping and truck movements for containers and found the latter can significantly reduce CO2 emissions. Patterson et al. (2008) examined the potential for reducing CO2 emissions in the Quebec city – Windsor corridor and found that intermodal transportation can reduce them by 50% when compared to truck-only transportation. 1
1361-9209/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.trd.2012.01.003
288
T.-A. Shiau, Y.-R. Chuang / Transportation Research Part D 17 (2012) 287–292
We create indicators for evaluating sustainability by considering economic, environmental, and societal aspects of the alternative modes. The economic aspect consists of indicators that describe the generalized costs from a customer’s viewpoint and includes transportation cost, transit time from origin to destination, traffic accident cost, and terminal operation cost. The environmental aspect consists of resource consumption, energy consumption, CO2 emissions, and toxic matter that adversely affections air and water quality. The social aspect consists of labor management, quality of life, damage caused by industrial operations, employee’s welfare and equity, and business development. Labor management consists of research and development, labor inputs, strikes and suspensions, and inputs for professional training. The damage caused by industrial operations is expressed in the number of fatalities, property damage, and production damage, with employee’s welfare and equity measured in terms of the percentage of disabled persons hired, family security, and the percentage of professional employees. Business development represents domestic and foreign investment, and imports from developing countries. Fig. 1 shows the hierarchical framework of these indicators. To construct the weighting scheme we use the analytic hierarchy process (AHP) (Saaty, 1980), allowing analyze of societal weights according to the hierarchical structure of measurable indicators (Fig. 1). For AHP applications, users first establish priorities among the elements of the hierarchy by constructing a series of pair-wise comparison matrices for the elements. Subsequently, the overall priorities for the hierarchy are determined by applying a linear additive decomposition principle. The consistency of the judgment is verified to ensure stable preferences. To measure and normalize performance indicators we use the performance of three kinds of transport based on doorto-door attributes. Truck-only transportation involves door-to-door service, while intermodal transportation must also consider line-haul and feeder transportation. A normalization process is used to allow meaningful aggregation of indicators.
Gravel transport sustainability
Society
Ecology
Efficiency
Terminal operation cost
Traffic accident cost
Transit time between O-D
Transportation cost
Toxicity potentials
CO 2 emissions
Energy consumption
Resources consumption
Business development
Employee welfare and equity
Damage caused by industrial operation
Quality of life
Labor management
Air pollutants
Water pollutants
Imports from developing countries
Capital investment
Foreign investment
Family security
The percentage of professional employees
The percentage of disabled persons hired
Property damage
Production damage
Number of fatalities
Inputs for professional training
Labor inputs
Strikes and suspensions
Research and development
Fig. 1. Gravel transport sustainability indicators.
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T.-A. Shiau, Y.-R. Chuang / Transportation Research Part D 17 (2012) 287–292
Keelung port ; Taipei port
Hualian port Water transport Ship Highway transport
Highway transport Truck
Truck
Highway transport Truck
Truck
Truck
Highway transport
Highway transport
Rail transport Train Wu-Du station
Shing-Cheng station Legend
Singer supply node Multiple demand nodes
Two ports in destination Train station
Single port in origin Line-haul transport
Feeder transport Fig. 2. Gravel transportation options in Taiwan’s northeast corridor.
A weighting scheme aggregates the normalized indicator performance values into economic, environmental, and societal aspects. Subsequently, three aspects are aggregated to calculate gravel transport sustainability. Fig. 2 shows the gravel transportation network in the northeast corridor of Taiwan. Eastern Taiwan is rich in gravel resources and acts a supplier to the rest of the country while northern Taiwan is a highly urbanized region that demanding a considerable amount of gravel for construction. Water transportation starts at Hualian port and ends at Keelung port or Taipei port; unlike Taipei Keelung port does not allow warehousing for gravel because of its limited inland area. Railway transport starts at Shing–Cheng station and ends at Wu–Du station; both stations having land available for gravel warehousing. 3. Results The Taipei metropolitan area in northern Taiwan has a population of over six million and we assess the implications of gravel transport to it from Hualian. Wu–Du station and Keelung port are located to the east of the Taipei metropolitan area, while Taipei port is on the western side. We assess gravel transport sustainability by considering destination nodes locating on the eastern side of the Taipei metropolitan area, while Keelung port is selected as the destination port (Fig. 2). We recruited 57 experts from the transportation research community and elicited their views on social weights. The questionnaire went to 19 individuals with social backgrounds, 19 with economic backgrounds, and 19 with environmental backgrounds. The experts are all concerned with gravel transportation along the northeast corridor. Only 18 usable replies were obtained, in part because of the complex pair-wise comparison procedure required when applying the AHP. These comprise five with social, seven with economic, and six with environmental interests. The two-stage geometric average from their responses was calculated and normalized to represent compromised societal weights (Table 1). During the first-stage, the geometric average is calculated based on individual professional background; a process iterated three times. During the second, the geometric average compromises the weights of three professional backgrounds. The final compromise weights are independent from unequal distributed representatives. Table 1 shows relatively consistent weights between societal, environmental, and economic aspects. The experts also recognized the following important indicators with weights
290
T.-A. Shiau, Y.-R. Chuang / Transportation Research Part D 17 (2012) 287–292
Table 1 Criteria weights for gravel transport sustainability assessment. Society: 0.300
Labor management: 0.051
Research and development: 0.011 Labor inputs: 0.013 Strikes and suspensions: 0.013 Inputs for professional training: 0.014
Quality of life: 0.072 Damages caused by industrial operation: 0.072
Employee’ welfare and equity: 0.051
Business development: 0.054
Environment: 0.370
Resource consumption: 0.089 Energy consumption: 0.089 Toxicity potentials: 0.092
Number of fatalities: 0.032 Property damage: 0.020 Production damage: 0.020 Percentage of disabled persons hired: 0.014 Family security: 0.017 Percentage of professional employees: 0.020 Capital investments: 0.019 Foreign investments: 0.017 Imports from developing countries: 0.018
Air pollutants: 0.050 Water pollutants: 0.042
CO2 emissions: 0.100 Economy: 0.330
Transportation cost: 0.086 Transit time between O–D: 0.076 Traffic accident cost: 0.102 Terminal operation cost: 0.066
Table 2 Normalized performance of economic aspect for gravel transportation. Indicator
Mode
Transportation cost (TWD/T) Transit time between O–D (Minutes) Traffic accident cost (TWD/T) Terminal operation cost (TWD/T)
Truck-only
Rail combined with truck
Ship combined with truck
1.00 0.33 1.00 0.57
0.68 0.38 0.08 0.76
0.52 1.00 0.16 1.00
(490) (330) (234) (79)
(335) (385) (18) (105)
(254) (1015) (38) (138)
Notes: The parenthesis indicates the original performance.
Table 3 Normalized performance of environmental aspect for gravel transportation. Indicator
Resource consumption Energy consumption CO2 emissions Toxicity potentials
Mode Truck-only
Rail combined with truck
Ship combined with truck
1.00 1.00 1.00 1.00
0.18 0.53 0.35 0.80
0.86 0.73 0.71 0.83
Table 4 Normalized performance of social aspect for gravel transportation. Indicator
Labor management Quality of life Damages caused by industrial operation Employee’ welfare and equity Business development
Mode Truck-only
Rail combined with truck
Ship combined with truck
0.69 0.63 1.00 1.00 0.42
1.00 1.00 0.31 1.00 0.12
0.80 0.24 0.25 1.00 1.00
exceeding 0.080; resource consumption, energy consumption, CO2 emissions, toxicity potentials, transportation cost, and traffic accident cost. In terms of the impacts of various gravel transport options, Table 2 illustrates their performance in economic terms. Truck-only transportation has the advantages of door-to-door service and shortest transit times between O–D compared to intermodal alternatives; ship in conjunction with truck has the longest transit time between O–D. Other indicators, including transportation cost, traffic accident cost, and terminal operation cost were measured on a monetary basis.
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T.-A. Shiau, Y.-R. Chuang / Transportation Research Part D 17 (2012) 287–292 Table 5 Gravel transport sustainability measurement. Aspect
Efficiency Ecology Society Total
Mode Truck-only
Rail combined with truck
Ship combined with truck
0.33 (1.42) 0.34 (1.26) 0.23 (1.10) 0.90
0.19 (0.81) 0.20 (0.71) 0.20 (1.00) 0.59
0.18 (0.76) 0.30 (1.09) 0.18 (0.88) 0.66
Notes: The parenthesis indicates the value calculated by SEEcube basis.
Our results show that truck-only transportation is more expensive then intermodal transportation; ship combined with truck intermodal transportation being the cheapest. A trade-off between transportation cost and transit time is seen for all modes. To eliminate the effects of measurement units, the performance of each transportation mode was normalized using;
Eij ¼ Pij =ðMax Pij ; 8 iÞ
ð1Þ
where Pij is the performance of mode j measured by criteria i; Eij is the normalized value of Pij. The value of Eij indicates that less is preferable. Table 3 shows the normalized performance in terms of environmental impacts. Energy consumption for transportation and terminal use are included, with electricity consumption translated into primary energy usage and based on the power generation mix. In this context, truck-only transportation is the worst performer, and rail in conjunction with truck intermodal transportation best. Resource consumption and CO2 emissions are estimated based on energy consumption and its related transformation factors. The performance rankings in these items are identical to energy consumption. The environmental aspect also includes air pollutants HC, CO, NOx, and SOx, and estimates water contaminants, COD, BOD, SS, SO2 4 , and HC. We use a scoring system based on effluent standards established by Taiwan’s Environmental Protection Administration, and normalize the results (Table 3). We finds that truck-only transportation performs worst in terms of these toxic pollutants with railroad in conjunction with truck the best. Using Eq. (1) to measures and normalizes social aspects (Table 4), the three modal options performance equally in terms of employee’s welfare and equity. Truck-only transportation performs the best in labor management but the worst in terms of damage caused by industrial operation. Rail in conjunction with truck transportation performs the best in business development, and the worst in labor management and quality of life. Ship combined with truck is the best performer regarding quality of life and damages caused by industrial operation, and the worst in business development. Multiplying the societal weights (Table 1) by the normalized performance values (Tables 2–4) yields the weighted normalized performances of the three gravel transportation modes (Table 5). The weighted normalized performances of the three aspects is also adjusted based on the SEEcube references (the average of the weighted normalized performances is set to unity). Table 5 shows that truck-only transportation performs the worst in terms of our sustainability measure with rail combined with truck the best. Ship associated with has benefits in terms of both economic and social features. In terms of the intermodal options, on social-efficient criteria, ship combined with truck performs better than rail in conjunction with truck, but overall, rail combined with truck is the best mode with respect to transport sustainability. Interviews with management of a gravel company that moves large amounts of gravel from Hualian to the eastern side of the Taipei metropolitan area finds it uses rail in conjunction with truck because: It was as authorized to construct a warehouse at Wu–Du station, and the land rent is reasonable. Compared to truck-only transportation, the costs including transportation and warehousing are attractive. Even though rail combined with truck requires more transit time than truck-only transportation, a pre-scheduled plan can help respond to demand uncertainty. The warehouse at Wu–Du station is a used as buffer to balance supply and demand. Moreover, Wu–Du station is close to the final market, and this effectively reduces demand uncertainty. We apply sensitivity analysis to obtain additional information regarding Taipei port as the destination port (Fig. 2). While in this particular case, the sustainability ranking for the three transportation modes is the same as in Table 5, the score for rail combined with truck is closer to ship combined with truck. Sensitivity analysis, further shows that ship and truck intermodal transportation has an advantage for some areas of demand close to the port at Taipei. For traffic movements when the destination nodes involves Wu–Du station and Keelung port and are located on the eastern side of Taipei metropolitan area, our sensitivity analysis shows that rail combined with truck is the most competitive mode in terms of sustainability. When the destination node involving Taipei port are located on the western side of the Taipei metropolitan area, with Wu–Du station located on the eastern side, rail in conjunction with truck has a competitive advantage despite the terminal’s location.
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4. Conclusions Gravel movements in the northeast corridor of Taiwan currently depend heavily on highway transportation, but heavy trucks damage pavements, disturb frail geology, and can cause serious traffic accidents. The results of our SEEbalanace analysis support shifting to alternative intermodal transportation options; although truck-only transportation has the advantages of door-to-door service and the shortest transit times between O–D performs it performs less well in terms of overall sustainability compared to alternative intermodal transportation. Rail in conjunction with truck improves transport sustainability the most. Ship in conjunction with truck intermodal transportation performs almost the same as rail combined with truck when the destination node is located on the western side of the Taipei metropolitan area. References Kölsch, D., Saling, P., Kicherer, A., Grosse-Sommer, A., Schmidt, I., 2008. How to measure social impacts? A socio-eco-efficiency analysis by the SEEBALANCE method. Int. J. Sustain. Dev. 11, 1–23. Liao, C.-H., Tseng, P.-H., Lu, C.-S., 2009. Comparing carbon dioxide emissions of trucking and intermodal container transport in Taiwan. Transp. Res. D 14, 493–496. Patterson, Z., Ewing, G.O., Haider, M., 2008. The potential for premium-intermodal services to reduce freight CO2 emissions in the Quebec City–Windsor Corridor. Transport. Res. D 13, 1–9. Saaty, T.L., 1980. The Analytic Hierarchy Process. McGraw-Hill, New York. Saling, P., Maisch, R., Silvani, M., König, N., 2005. Assessing the environmental-hazard potential for life cycle assessment, eco-efficiency and SEEbalance. Int. J. Life Cycle Assess. 10, 364–371.