Journal of the Eastern Asia Society for Transportation Studies, Vol.12, 2017
Reasons behind Changes in Customer Satisfaction with Expressways in Japan
Tomohiro KAGEYAMA a, Shintaro TERABE b, Hideki YAGINUMA c, and Nan KANG c
a Department of Civil Engineering, Tokyo University of Science, 2641 Yamazaki, Noda-shi, Chiba 278-8510, Japan, E-mail: [email protected] b E-mail: [email protected] c Department of Civil Engineering, Tokyo University of Science, 2641 Yamazaki, Noda-shi, Chiba 278-8510, Japan
Abstract: Since privatized from Japan Highway Public Corporation in 2005, three Nippon Expressway Companies (NEXCOs) have surveyed the customer satisfaction for more than ten years. The score of satisfaction is one of the key performance indicators which explain the difference between customers’ expectation and experience. This paper shows the change of satisfaction during the decade and possible factors affecting the result of survey. We confirmed that network extensions and facility improvements increased the satisfaction scores. Aging respondents also helped to increase the score. On the other hand, the negative effects were from an earthquake and a major accident. There is a combination of positive and negative effects that changes the satisfaction scores over the years.
Keywords: Customer Satisfaction, Performance Measures, Key Performance Indicator, Expressway, T-test
1. INTRODUCTION
Customer satisfaction surveys are used by many private companies for ex post evaluation of customer experience. The method is also now used by public corporations that provide transportation services. Three Nippon Expressway Companies (NEXCOs), which are limited government-owned companies that operate and maintain expressways in Japan, carry out an annual customer satisfaction survey for users of the expressways network every year to understand customer satisfaction. The survey has been required by the government since the privatization of the Japan Highway Public Corporation in 2005. There are two reasons why it is important to analyze customer satisfaction quantitatively. First, the survey must indicate the user satisfaction. Second, it is unknown whether the change in satisfaction is related to service improvement and maintenance by NEXCO. This research identifies factors that affect user satisfaction.
2. CHALLENGES IN INTERPRETING SATISFACTION SURVEYS
Customer satisfaction is defined as the difference between the initial expectation and the perceived value after experiencing a service. It is high when the experience exceeds preliminary expectations and low when the service is worse than expected. Quantitative evaluation of customer satisfaction surveys can indicate the quality of the service based on the subjective views of users. The efficiency of the business can be increased by finding and closing the gap between the users’ needs and the service level.
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However, because of the subjective nature of the responses, the survey results may not be related to the latest service experiences directly, and could be affected by the respondent’s past experiences, environmental factors, and socioeconomic status. Changes in mean satisfaction score do not necessarily reflect the changes in the level of satisfaction or service. Customer satisfaction should be analyzed in terms of both the service and management by NEXCO, and taking account of various factors including the national mood and socioeconomic attributes of the respondents. In addition, the service and management by NEXCO should be broken down by the sections of the expressway system.
There are many studies about customer satisfaction with public transit. For example, Friman, M. (2004) addresses two questions: (1) What effect does quality improvement have on satisfaction with public transport services? (2) What effect does quality improvement have on passengers’ perceived frequency of negative critical incidents? The main conclusion of her study is that the satisfaction people experience when using public transport services is influenced by quality improvements only to a limited extent. Furthermore, the effect was directionally opposite in that respondents reported less satisfaction and higher frequencies of negative critical incidents after the quality improvements had been implemented. Eboli and Mazulla (2011) proposed a methodology for measuring transit service quality. They considered passenger perceptions to be fundamental because the customer's point of view is very relevant for evaluating the performance of a transit service. They used customer satisfaction with 26 fields of services as subjective indicators so as to combine with objective indicators which shows service quality. Mouwen (2015) analyzed a dataset containing the satisfaction scores of urban and regional Dutch PT users (bus, tram, metro and regional train), in total approximately 180,000 passengers. He shows that PT users see the service attributes such as on-time performance, travel speed, and service frequency as the most important, followed by personnel/driver behavior and vehicle tidiness. There are several studies which show customer satisfaction is affected by expressway expenditure. Paz et al. (2016) analyzes the satisfaction of the Nevadans with respect to their highways transportation system and the corresponding expenditures of Nevada Department of Transportation (NDOT). The results indicate the customer satisfaction is decreasing with respect to traffic safety as well as customers’ satisfaction increases with the expenditures associated with reduction of congestion in some parts. According to Gallup's 2015 50-State poll, Jones (2016), state spending on roads is positively related to satisfaction levels. Sakai et al. (2011) produced a level of service (LOS) measure that is consistent with a driver's subjective evaluation from the viewpoint of customer satisfaction. They used individual response data obtained through in-laboratory experiments with video images, and estimated driver satisfaction models composed of traffic environment perception by structural equation modelling. This study showed customer satisfaction is affected by subjective evaluation by each participant. Our study can be compared with those two papers , Ishibashi et al. (2004) and Suenoka et al. (2008). Whereas they explain the relationship between LOS, objective indicators, and the results of customer satisfaction survey, there are some limitations about data used in terms of sample size and regional coverage. Our approach is similar to above two studies, however, the novelty of our study is to seek why the satisfaction is changed for a certain period of time by analyzing data of national customer satisfaction survey for 11 years. In addition, we focused on the effects associated with network improvement including extension of expressways network and interchange development, accidents and disasters documented in news articles and news releases rather than objective measurements such as traffic volume, travel time and expenditure on expressways improvement.
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This study can contribute for practitioners rather than academic people. The authors have heard from the people in charge of expressway maintenance that the survey result may not reflect the actual investment or improvement. Those practitioners sometimes puzzled about the result changed from the previous year. The authors tried to show the reasons behind the changes in customer satisfaction in this research.
3. DATA
This study uses individual responses to customer satisfaction surveys about NEXCO over 11 years (Table 1).
Table 1. Details of customer satisfaction survey Item Description Purpose To measure customer satisfaction with maintenance in the past year Respondents (1) People who are over 18 and have a driver’s license. (2) People who have used an expressway within the year. (3) People who live in Japan. Number of samples Nationwide: 6000–10,000, (eastern Japan: approx. 3000; central per year Japan: approx. 2000; and western Japan: approx. 3000), varies with year. The extraction rate was decided based on the traffic volume on expressway. Survey time November, from 2005 to 2015 Survey method Web questionnaire survey Evaluation Five-point scale Survey items Overall and divisional (*) satisfaction with service (about 60 items), personal attributes of the respondent, name of the expressway and rest facilities evaluated * Divisional satisfaction comprises satisfaction with safety, comfort, reliability, information, tolling facilities, and rest facilities.
A satisfaction score of 5 is fully satisfactory, 4 is partially satisfactory, 3 is neither satisfactory nor dissatisfactory, 2 is partially unsatisfactory, 1 is unsatisfactory. Additional ten questions asking respondents to evaluate different items were added to the original questionnaire, and the order of questions was changed so that complaints about service directly affected overall and divisional satisfaction in 2014. This marked change removed the ability to compare with scores from previous years. In 2015, these changes were reverted, giving the same questionnaire as in 2013.
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4. BASIC ANALYSIS
4.1 Overall and Divisional Satisfaction
Changes in the overall and divisional satisfaction over 11 years are shown in Figure 1. The overall satisfaction rose until 2008, reached a maximum in 2010, decreased until 2014, and rose suddenly in 2015. The satisfaction score peaked at 3.65 in 2010 what we attribute with the toll-free experiment which began in June 2010. The Great East Japan Earthquake in March 2011 and the subsequent end of the toll-free experiment in June 2011 decreased the satisfaction score from 3.65 in 2010 to 3.60 in 2011. The decrease in 2013 resulted from the Sasago Tunnel ceiling collapse, which happened in December 2012. In addition, the score was affected by a major change in the form of the satisfaction survey questionnaire in 2014. We cannot provide any clear reason to support it. However, committee members of this survey agreed that this sudden drop was caused by the change of survey in 2014. The six divisional satisfaction scores show that the satisfaction with the rest facilities, safety, and comfort was higher than the satisfaction with the tolling facilities, reliability, and information. Even though the overall satisfaction fell from 2010 to 2013, the satisfaction with the rest facilities did not change greatly. Most users seemed satisfied with the rest facilities during this period. The decrease in the overall satisfaction from 2010 to 2013 was mainly caused by decreases in satisfaction with safety and comfort, because satisfaction with information and reliability did not decrease.
3.9 3.8 3.7 3.6 3.5 3.4
Satisfaction 3.3 3.2 3.1 3 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Year Overall satisfaction Safety Comfort Reliability Information Tolling facilities Rest facilities
Figure 1. Changes in customer satisfaction
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4.2 Customer Satisfaction of Each NEXCO Company
The overall and divisional satisfaction for each expressway company is examined next. The same satisfaction scores are separated according to regional NEXCO companies (Figures 2). Satisfaction with safety, comfort, and rest facilities was also higher than with the tolling facilities, reliability, and information. The New Meishin expressway between Kameyama and Otsu opened on February 23, 2008, and the Tokai Hokuriku expressway between Hida-Kiyomi and Shirakawago opened on March 11, 2008. These two extensions of the expressways network improved regional and inter- regional traffic substantially. Although they are located in NEXCO Central and NEXCO West, all satisfaction scores of the three regional NEXCO companies, including NEXCO East, increased from 2007 to 2008, and the difference in the means was statistically significant. The changes in satisfaction of each NEXCO company were similar to national changes in satisfaction. The toll-free experiment that began in June 2010, the Great East Japan Earthquake in March 2011, and the abolition of the toll-free experiment in June 2011 also affected the satisfaction score from 2010 to 2011. The effect of the Sasago Tunnel ceiling collapse in December 2012 was also a factor in the decrease in 2013. Divisional satisfactions were similar among the three NEXCO companies and the national average. However, satisfaction with the rest facilities of NEXCO Central increased continuously from 2006, except for a major change in the survey questionnaire in 2014. This means that the rest facilities of NEXCO Central have continued to improve their service and users are satisfied.
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4.4 4.2 4.0 3.8 3.6
Satisfaction 3.4 3.2 3.0 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Year
(a) NEXCO East
4.4 4.2 4.0 3.8 3.6
Satisfaction 3.4 3.2 3.0 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Year
(b) NEXCO Central
4.4 4.2 4.0 3.8 3.6
Satisfaction 3.4 3.2 3.0 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Year
(c) NEXCO West
Figure 2. Difference among Three NEXCOs about change of customer satisfaction
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4.3 Difference among Age Groups
The overall satisfaction of each age group in is shown in Figure 3. Teens are not included in this figure because of the small number in the sample. The overall score was highest in the 60s age group during all years except for 2015. The 40s and 50s age groups were less satisfied than the other age groups. There was a large, sudden increase in the 20s age group in 2015. The increase was similar in all six divisional satisfaction scores. If the sudden decrease in 2014 caused by the major change in the questionnaire is ignored, the 20s age group appear to satisfy with about the expressway from 2013 onwards for reasons we do not understand.
3.9
3.8
3.7
3.6
3.5
3.4 Satisfaction 3.3
3.2
3.1
3 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Year
20s 30s 40s 50s 60s
Figure 3. Age group difference of customer satisfaction
Figure 4 shows the share of satisfaction score for each age and gender group in 2005. Teens are also omitted from this figure because of the small number of respondents. A satisfaction score of 5 is fully satisfactory, 4 is partially satisfactory, 3 is neither satisfactory nor dissatisfactory, 2 is partially unsatisfactory, 1 is unsatisfactory. Most of respondents gave scores of 3 or 4, older female users tended to give more scores of 5, and males in their 20s, 30s, and 40s tended to give scores of 1 or 2.
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F60s F50s F40s F30s 1 F20s 2 M60s Group 3 M50s 4 M40s 5 M30s M20s
0% 20% 40% 60% 80% 100% Cumulative
Figure 4. The share of satisfaction score of each age and gender groups in 2005
4.4 Effect of Aging on the Number of Samples in the Age and Gender Groups
The number of samples in each age and gender group is shown in Figure 5. The intermediate age group (40s) did not change greatly from 2006 to 2015 overall, whereas the number of samples in the senior group (50 and over) increased and that in the younger age group (below 30) decreased. The respondents may be getting older because younger people no longer need to own cars, the number of young drivers has decreased, and younger generations may not express their opinions on expressways. The number of samples from male drivers exceeded 70% in most fiscal years. This may be because many men use cars to commute and work. 12000
10000
F60s F50s 8000 F40s F30s F20s 6000 F10s M60s
Number of of Number samples 4000 M50s M40s M30s 2000 M20s M10s
0 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Year Figure 5. The number of sample divided in age and gender group
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The mean, standard deviation, maximum, and minimum of the respondents’ age for each year are shown in Figure 6 as box plots. The average age of the sample increased every year except for 2013-2014. The number of samples from senior users increased and the number of samples from the younger age group decreased, consistent with Figure 5.
110
100
90
80
70
60
Age 50
40
30
20
10
0 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Year
Figure 6. Age distribution (mean, standard deviation, maximum and minimum) of respondents in each year
5. REASONS FOR CHANGING SATISFACTION WITH SECTIONS OF EXPRESSWAY
5.1 Finding Key Expressway and Sections by Statistical Test of the Difference
The satisfaction scores depended not only the year, age, and gender but also on the expressway and sections that the respondents used. They chose one section of expressway when they responded to the customer satisfaction survey. To identify the key expressway sections, we performed a statistical test of the difference between two sequential means of satisfaction score as follows. 1) We statistically tested the difference between two overall satisfaction scores for sequential years. Data in 2014 was excluded from this analysis because there was a major change in the questionnaire, which affected the satisfaction score. 2) When we found two sequential years with a change in mean scores, we compared the scores among the NEXCO East, NEXCO Central, and NEXCO West companies. The P-value obtained by the procedures so far are shown in Table 2. 3) After identifying differences among the three companies, we compared the scores of each section of expressway. 4) We chose sections that had more than 100 samples and identified its satisfaction scores showed a statistically significant increase or decrease between two sequential years.
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Table 2. P-value pf Difference Overall about satisfaction 2005-2006 2006-2007 2007-2008 2008-2009 2009-2010 2010-2011 2011-2012 2012-2013 2013-2014 2014-2015 Nationwaide 0.075 0.015 0.000 0.211 0.125 0.000 0.048 0.050 0.000 0.000 NEXCO East 0.722 0.055 0.014 0.226 0.087 0.000 0.073 0.762 0.000 0.000 NEXCO Central 0.289 0.634 0.000 0.113 0.751 0.612 0.321 0.127 0.000 0.000 NEXCO West 0.086 0.101 0.000 0.053 0.594 0.047 0.526 0.026 0.000 0.000
We applied this procedure and identified the following six sections as having significant changes in two sequential years. Chuo Expressway (Takaido Interchange (IC)-Otsuki IC/Kawaguchiko IC), 2007–2008 Tohoku Expressway (Shirakawa IC-Ichinoseki IC), 2007–2008 and 2010–2011 Kyushu Expressway (Moji IC-Kagoshima IC), 2010–2011 Meishin Expressway (Yokaichi IC-Nishinomiya IC and Oyamazaki Junction (JCT)- Kumiyamayodo IC), 2012–2013 Kinki Expressway (Suita JCT-Matsubara JCT), 2012–2013 Sanyo Expressway (Kobe JCT-Bizen IC and Miki JCT-Kobe West IC), 2012–2013
Hence, the changes in these sections affected the changes in overall satisfaction. We examined possible reasons for the changing satisfaction scores by considering service improvement, network extension, accidents, and disasters during those years.
5.2 Discussion of Each Expressway
Changes in the satisfaction scores for the six expressways are shown in Figures 7–12. In addition to the scores for two consecutive years, we show the scores for 11 years, because we expect that experience in the previous one or two years may affect the evaluation. The scores help to elucidate the reasons behind the change in satisfaction. For example, when a significant difference is confirmed for 2007–2008 on an expressway, it is necessary to consider a time lag in the effect of an improvement performed on the expressway from 2005 to October 2008. Therefore, we look at events in the previous two years.
5.2.1 Chuo Expressway (Takaido-Otsuki and Kawaguchiko)
In the satisfaction score for the Chuo Expressway (Figure 7), there is a significant increase from 2007 to 2008 (P=0.002). There were two major network extensions around these years. Chuo Expressway was connected with Tokai-Kanjo Expressway by Toki JCT (March 19, 2005) and Ken-O Expressway (Metropolitan Inter-City Expressway) by Hachioji JCT (June 23, 2007). Smart ICs, which are inexpensive ramps only for passenger cars, were built between existing ramps to increase accessibility at Futaba (opened October 1, 2006) and Iida-Yamamoto (opened April 13, 2008), and increased the satisfaction of drivers using this expressway. Only Hachioji JCT is in this section and the other projects, including network extension and smart ICs, are out of the section but on the same, Chuo Expressway. However, these projects for NEXCO Central had indirect effects on the satisfaction of this section of the same expressway.
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4.4
4.2
4
3.8
3.6
Satisfaction 3.4
3.2
3 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Year
Overall satisfaction Safety Comfort Reliability Information Tolling facilities Rest facilities
Figure 7. Changes of customer satisfaction with Chuo Expressway
5.2.2 Tohoku Expressway (Shirakawa-Ichinoseki)
There was a significant increase in satisfaction score from 2007 to 2008 (P=0.011) for the Tohoku Expressway (Shirakawa-Ichinoseki) (Figure 8). Six smart ICs were built in this time: Fukushima-Matsukawa Smart IC and Chojahara Smart IC (October 1, 2006); Kami-Kawachi Smart IC, Nasu-Kogen Smart IC, and Izumi Parking Area Smart IC (April 1, 2007); and Kagamiishi Parking Area Smart IC (September 14, 2007). These improvements in accessibility for local traffic may have contributed to the increase in the score. In contrast, there was significant decrease in satisfaction score from 3.68 in 2010 to 3.44 in 2011 (P=0.026) in the same expressway, although there was an increase from 2009 to 2010. There was much development of ICs in 2009 and network extensions in 2010, such as Tomiya JCT (connection to Sendai North Road; March 27, 2010), Iwafune JCT (connection to North Kanto Expressway; April 17, 2010), and Ohira IC, Kami-Kawachi Service Area Smart IC and the Nasu-Kogen Service Area Smart IC (December 18, 2010). These developments were welcomed by expressway users and increased the customer satisfaction score in 2010. On March 11, 2011, the Great East Japan Earthquake struck causing considerable damage to this section of expressway. The 630 km of expressway between Kawaguchi JCT and Ikarigaseki IC was completely closed until April 10 for emergency repair work. Comprehensive repair work was performed from September 5 to December 22, 2012. Although there were two IC improvements to Sano Service Area Smart IC (April 28, 2011) and Kuki Shiraoka JCT, which connects to Ken-O Expressway (Metropolitan Inter-City Expressway) (May 29, 2011), they did not play a big role after the earthquake. Even if an expressway company improves convenience in several ways, a big earthquake will decrease satisfaction. The most significant factor was lane closures due to the Great East Japan Earthquake; however, this historic major earthquake may have had a considerable negative influence on people's sentiment, and caused a decrease in the satisfaction score in 2011. This effect was also found in the overall satisfaction of the whole country.
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The satisfaction scores after 2012 recovered to 3.58 in 2013. This may be due to the toll- free program from December 1, 2011 to March 31, 2012, which applied to all vehicles between Shirakawa IC and Ashiro IC and to passenger vehicles between Ashiro IC and Aomori IC on weekends. 4.4 4.2 4 3.8 3.6
Satisfaction 3.4 3.2 3 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Year
Overall satisfaction Safety Comfort Reliability Information Tolling facilities Rest facilities
Figure 8. Changes of customer satisfaction with Tohoku Expressway
5.2.3 Kyushu Expressway (Moji-Kagoshima)
There was a significant increase in satisfaction score for Kyushu Expressway (Moji- Kagoshima) from 3.50 in 2010 to 3.70 in 2011 (P=0.013) (Figure 9). Some IC ramps were opened, including Yanagawa IC (March 29, 2009), Kurate IC (February 19, 2011), and Miyada Smart IC (March 26, 2011), which increased the overall satisfaction score. This increase in the satisfaction score was reflected in the lower score in 2010 than 2009. One of the reasons for the lower score was a lane closure between Fukuoka IC and Dazaifu IC due to a mud slide between Sue Parking Area and Dazaifu IC by heavy rain on July 26, 2009. The lane was reopened on August 12, 2009 when the regulations regarding maximum speed and cumulative rainfall were enforced more strictly than before. This is also an example of a natural disaster that affected transportation reliability and user anxiety, resulting in dissatisfaction. For the Kyushu Expressway, there was no decrease from 2010 to 2011, as observed for the other areas due to the Great East Japan Earthquake. This area is far from the Tohoku area and users were not affected by the disaster. The Kumamoto Earthquake on April 14, 2016 will affect the score of this expressway in 2016. All the sections between Nankan IC and Ebino IC were closed for 15 days due to damage caused by fallen bridges, cracked and collapsed pavements, and bank slides along the expressway. This effect should be confirmed after we get the latest customer satisfaction survey results in 2016.
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4.4 4.2 4 3.8 3.6
Satisfaction 3.4 3.2 3 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Year
Overall satisfaction Safety Comfort Reliability Information Tolling facilities Rest facilities
Figure 9. Changes of customer satisfaction with Kyushu Expressway
5.2.4 Meishin Expressway (Yokkaichi-Nishinomiya and Oyamazaki JCT-Kumiyamayodo)
There was a significant decrease from 3.70 to 3.47 in the overall satisfaction during 2012–2013 (P=0.011) for the Meishin Expressway (Yokkaichi-Nishinomiya and Oyamazaki JCT- Kumiyamayodo) (Figure 10). We could not identify any reasons for this decrease around this period. However, there were network extensions including the opening of Yoro JCT connected with Tokai Kanjyo Expressway between Ogaki West IC and Yoro JCT (September 15, 2012), Oyamazaki JCT connected with the Kyoto Jyukan Expressway between Kutsukake IC and Oyamazaki IC (April 21, 2013), and Koto Mitsuyama Smart IC (October 21, 2013). 4.4 4.2 4 3.8 3.6
Satisfaction 3.4 3.2 3 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Year
Overall satisfaction Safety Comfort Reliability Information Tolling facilities Rest facilities
Figure 10. Changes of customer satisfaction with Meishin Expressway
5.2.5 Kinki Expressway (Suita JCT-Matsubara JCT)
All the satisfaction scores apart from the rest facilities score decreased during 2012–2013 (P=0.003) (Figure 11). We could not identify a reason for the decrease in customer satisfaction
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around this period. This expressway was connected with Daini Keihan Road at Kadoma JCT on March 20, 2010, and was widened to six lanes from four lanes. These improvements did not affect the satisfaction after 2010 greatly, although the project improved the traffic capacity of this expressway. Also, we can see a hockey stick effect on the satisfaction with rest facilities. The reason for this is believed to be attributed to the small number of sample sizes answered to the rest facilities.
4.4 4.2 4 3.8 3.6
Satisfaction 3.4 3.2 3 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Year
Overall satisfaction Safety Comfort Reliability Information Tolling facilities Rest facilities
Figure 11. Changes of customer satisfaction with Kinki Expressway
5.2.6 Sanyo Expressway (Kobe JCT-Bizen IC and Miki JCT-Kobe West IC)
Between 2012 and 2013 (P=0.010), projects to improve service quality along the Sanyo Expressway were carried out that may have affected the satisfaction scores (Figure 12). The projects were the Takaya JCT and IC and the connection to Higashi Hiroshima Kure Expressway and Higashi Hiroshima Takada Expressway (March 14, 2010), the Onomichi JCT connection to the Onomichi Expressway (November 27, 2010), and the network extension with the Yamaguchi Ube Toll Road (March 28, 2012). However, the satisfaction score for this period decreased from 3.83 to 3.56 despite these improvements. The decrease may have been caused by the Sasago Tunnel ceiling collapse, which we discussed in Sections 4.1 and 4.2. However, this expressway is far from the Sasago Tunnel and there was no effect on the traffic on this expressway. The satisfaction of the whole country, NEXCO Central, and NEXCO West, as well as that of the Chuo Expressway near Sasago Tunnel decreased from 2012 to 2013. The Sasago Tunnel collapse or causing them to evaluate this expressway negatively.
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4.4
4.2
4
3.8
3.6 Satisfaction 3.4
3.2
3 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 Year
Overall satisfaction Safety Comfort Reliability Information Tolling facilities Rest facilities
Figure 12. Changes of customer satisfaction with Sanyo Expressway
6. CONCLUSION
We examined possible reasons for the changes in the customer satisfaction scores for expressways in Japan after a statistical test that compared the satisfaction scores in two sequential years. We confirmed that network extensions and facility improvements increased the satisfaction scores. Aging respondents also helped to increase the score because senior people evaluated the service better than middle-aged people. The negative effects on the customer satisfaction scores were a major earthquake in 2011, a major accident in 2013. Changes to the questionnaire in 2014 also decreased the score. Further studies to analyze the customer satisfaction scores from a structural viewpoint are required. Evaluation should consider transportation service, generational effects and economic background. The transportation service comes from traffic volume and travel speed, which were not considered in this paper, since only limited data were available. Generational effects are based on the respondents’ personal attribute, including gender and age. We could only aggregate gender and age into groups in this study; however, regression analysis may help to explain the relation between satisfaction score and personal attributes. As for economic background, wider economic influences, including GDP, income, and unemployment, may affect some aspects of satisfaction. In the future, we will use survival analysis, regression modeling, etc. to quantitatively evaluate how these components affect customer satisfaction. Also, it is necessary to review the t-test which is the analysis method of this research. The data used in this study is based on a survey conducted in different sample populations for each year. Therefore, it is not regarded as sequential data, but the difference between years is tested by t test, but it is also possible to perform analysis of variance which cannot be seen as sequential data. For that purpose, we will make future analysis of variance analysis. Also as a future subject, relative quality improvements, promotions in other modes (like intercity rail, high-speed rail or Shinkansen, air travel) may also have impacts on customer satisfaction with expressways over the time.
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ACKNOWLEDGEMENTS
The authors would like to acknowledge with the Nippon Expressway Research Institute Company Limited (NEXCO RI), East Nippon Expressway Company Limited (NEXCO East), Central Nippon Expressway Company Limited (NEXCO Central) and West Nippon Expressway Company Limited (NEXCO West) for supporting this research.
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