# Quantitative Analysis

Introduction
Nanjing Metro is an urban rail service serving Nanjing and the metropolitan area of Nanjing. Its first line was officially opened on May 15, 2005, making Nanjing the sixth metropolitan city in Mainland China following Beijing, Tianjin, Shanghai, Guangzhou and Shenzhen.
Until the end of 2017, Nanjing Metro has opened 9 lines for a total of 164 stations. The total length of the lines is 347 kilometers. The total length of lines in China is No. 4 (after Shanghai, Beijing and Guangzhou) and the 7th in the world. Constitute a subway network covering 11 city districts in Nanjing. The daily passenger flow of the subway is 2,980,000 passengers in 2017 , an increase of 409,000 passengers from 2016, and the growth rate is 18.01%. The cumulative passenger flow was 977 million passengers, an increase of 147 million passengers compared to 2016. As of March 2018, Nanjing subway had the highest daily passenger volume of 3.653 million passengers, ranking fifth in China. It is estimated that by 2030, Nanjing Metro will build 25 subway lines with a total length of 1011.2 kilometers.
| Name | Nanjing Metro | Rail type | Metro |
| Opening date | 5th May 2005 | Operate mileage（2017） | 347 km |
| Stations number（2017） | 164 | Official language | Chinese\English |
| Daily average passenger traffic（2018） | 3,100,000 | Daily highest passenger traffic（2018） | 3,650,000 |
| Yearly traffic（2017） | 977,110,000 | Operating Company | Nanjing Metro Group Co., Ltd. |
* The timeline of construction:
| Lines | Mileage  km | Loco Color | Opening time |
| L 1 | 38.9 | Blue | 15/05/2005 |
| L 2 | 37.95 | Red | 28/05/2010 |
| L S3 | 36.22 | Green | 06/12/2017 |
| L 10 Term 1 | 21.6 | Purple | 01/07/2014 |
| L S1 | 35.8 | Champagne | 01/07/2014 |
| L S8 Term 1 | 45.2 | Gem Green | 01/08/2014 |
| L 3 | 44.9 | Pink Purple | 01/04/2015 |
| L 4 Term 1 | 33.8 | Dark Orange | 18/01/2017 |
| L S9 | 52.4 | Bright Yellow | 30/12/2017 |
* Metro Map
* Nanjing Metro Map
Features
* Advantage:
1. Saving land: Since the value of urban land in a typical metropolitan area is high, building a railway on the ground can save floor space and allow ground land to be used for other purposes.
2. Reduce noise: The railway is built underground and can reduce ground noise.
3. Reduce interference: As the driving route of the subway does not overlap or intersect with other transportation systems (such as ground roads), traffic disturbances caused by traffic are less, which can save a lot of commuting time.
4. Energy Conservation: Under the problem of global warming, the subway is the best mass transportation tool. Due to the stable speed of subway travel, a lot of commuting time is saved, so that the people are willing to take the ride and also replace many of the energy consumed by driving.
5. Reduce Pollution: The average car uses gasoline or oil as energy, while the subway uses electricity, there is no exhaust emissions, will not pollute the environment.
6. Urban Rail Transit Has High Punctuality and Comfort: Because urban rail transit is operated on a dedicated lane, it is not affected by other vehicles, does not cause line jamming, and is not affected by climate. It is an all-weather mode of transportation, and trains can operate on a map and have reliable punctuality. Compared with conventional public transportation, urban rail transit is operated on a line that is not interfered with by other vehicles. Urban rail vehicles have better running characteristics. Vehicles, stations and other air-conditioned, guided devices, automatic ticketing, etc. are directly used as passengers. The service equipment and urban rail transit have better ride conditions and their comfort is better than public trams and buses.
7. Urban Rail Transit Has High Security: Urban rail transit is running on a special track, has no level crossings, is free from interference from other vehicles, and has advanced communication signal equipment. It rarely causes traffic accidents.
* Limitation
1. High construction costs: Due to the need to drill underground, underground construction costs are higher than those built on the ground.
2. Long construction period: due to digging of tunnels, laying of rails, installation of equipment and various debugging work. It takes a long time for the subway to begin construction and put into operation.
3. Long-term early period: The construction of the subway has a relatively long period of time. Due to the need for planning and government approval, even a trial is required. It takes a very long time to start from the beginning of brewing and putting into action. It will be a short period of several years. It may be possible to grow for more than ten years.
4. Compared with other modes of transportation, the subway has a poor ability to deal with emergencies. For example, if an earthquake occurs, the subway may derail, and the subway structure in the seismic zone must be particularly strong. Faced with floods such as extreme natural disasters
Technology of Construction
* Hardware
The construction of the Nanjing Metro involves many professional technologies and managements, including the construction of the shields and arrivals, the technology of soft soil bite maintenance, the construction technology of the soft-bottomed shallow-buried undercutting method, and the construction of the tunnel under the shield tunnel. Wear construction technology, artificial freezing method, assembly technology of shield tunnel segments, construction technology of railway stations underneath existing railway stations, drainage construction technology of deep foundation pits, tunnel blasting excavation and vibration technology under construction, shield turning machine technology, etc.
* Software
The ticketing system of the Nanjing Metro is relatively complete and classified. There are three types of different ticket cards: 1. One-way coin ticket; 2. IC card and 3. Emergency ticket. Among them, IC cards are more classified, and they are also the latest ticket cards. Some types of IC cards can even be used in shopping malls, medical services, and restaurants (such as the Zhihui card), thus realizing the combination of traffic technology and other modes.
Early market
* Background
1. Bus system problems
Before 2005, the main means of public transportation for Nanjing citizens was buses. However, in 2005, the bus industry was hit hard. In 2003, the epidemic of SARS caused an impact on buses, a densely populated transportation system. The proportion of people using public buses fell to 24.1%. In theory, it will pick up in 2005. However, the proportion of public transport continues to fall, reaching 22%. 6%, the lowest in five years, compared to the loss of 40,000 passengers per day in 2003. In 2005 it also set two other longest records: the longest waiting time in the past seven years - 5.8 minutes and the longest transfer time in the past six years. People are increasingly dissatisfied with public transport. The focus of consumer dissatisfaction is: crowded, slow, and waiting. The conflict between passengers and bus companies becomes more and more obvious. According to a study, only 22.6 out of 100 Nanjing citizens are willing to travel by bus, and people are more and more willing to avoid the morning peak by making travel from 6 to 7 o'clock.
2. Population growth and structural change
From 1982 to 2005, the resident population of Nanjing showed an upward trend, rising from 4,491,100 to 6,889,000, and this trend is still maintained in the next few years. And the age structure is also changing, the proportion of labor groups (age 15-59) is increasing, and the corresponding demand for public transport will also increase. In 2006, the urbanized population reached 76.4% and in 2007 it increased to 76.82%.
3. Travel mode
From 2005 to 2009, it was Nanjing's birth phase. The growth rate of passenger traffic was only 196.3%. Take the middle year - 2007 as an example.
Proportion of travel mode in 2007
| Walking | Bus | Bike | Metro | Taxi | Moto | Company car | Private car | other |
| 26.32 | 40.14 | 19.3 | 2.16 | 2.09 | 1.4 | 3.66 | 4.31 | 0.58 |
In the early market, the subway did not dominate, and the proportion was very small. People prefer to walk and bike when they travel. There are two main reasons for this: First, the urban rail transport model has just emerged, and it needs time to adapt to the market and get acceptance from the market. Second, only one subway was in operation before 2009, and it cannot fully cover the market.
4. Market impact
Since its construction in 2005, the Nanjing Metro has had a certain impact on the transportation market. First of all, due to the characteristics of the subway itself, it can reduce the congestion of the ground traffic, thus improving the overall market quality and alleviating the pressure of other related transportation industries. Second, the emergence of the subway has changed the traditional mode of travel. High-efficiency operation is a unique advantage of the subway and will not be affected by problems such as traffic congestion. In addition, the emergence of new industries provides a large number of employment opportunities, from planning, construction to operations, can bring considerable job opportunities for the city. Finally, the emergence of the subway as a new model can be perfectly combined with the existing model. Long-distance travel within the city uses subways and short-distance travel uses public transportation to improve the city's accessibility.
Policy
* Policy of birthing phase
1. The government has set up a special organization in conjunction with various related industries - the Nanjing Rail Transport Industry Association (established in 2006). Its members cover various professional fields such as vehicle integration, road network signals, and comprehensive monitoring. The association has launched Nanjing rail transit products by organizing PPP, BOT and other general contracting models. Within the organization, mutual development is the top priority, and internal collaboration is strengthened.
2. Preferential policy
a. Transfers within a certain period of time can be discounted.
b. Issue different bus cards to discount special populations
c. Different models of preferential sharing
* Policy of growth phase
1. Phenomenon and problems
Since the opening of the Nanjing Metro in 2005, with the increase of subway opening lines, lower passenger flow intensity on new lines, aging facilities, fares and government expenditures and other factors, the Nanjing Metro has suffered serious operating losses, and the form of sustainable development of the subway is severe.
2. Corresponding policy
a. Define the scope of subsidies and implement classified subsidies policies. Subsidize maintenance updates for the relevant subway lines
b. ‘Special Subsidy’ is combined with 'Annual Subsidy' to combine financial subsidies with business performance to effectively separate policy losses from operating losses
c. Conduct operational cost regulation. As soon as possible, the Nanjing Metro will carry out operational cost regulation work, carry out special audits on the financial status of the subway operation, and provide annual financial subsidies based on the audited and approved amount, so as to ensure the healthy and sustainable development of rail transit in the city.
Policy impact
During the birth phase of Nanjing Metro, China was still in the early stages of subway construction and lacked experience and professional team. Although nationalized production is already capable, the market’s credibility is not enough and it is difficult to compete with foreign investors in project bids. At this time, the introduction of some protective policies ensured the development and rise of nationalization and stabilized the initial foundation in the market. The government's regulation of the market is very tough and lays the foundation for the stable development of the state-owned core technology of the metro.
In addition, in cooperation with private companies, the introduction of humane subway services, such as IC cards, including the Zhihui card, can be used not only for subway, bus and other transportation, but also for shopping in the mall, consumption in the restaurant, and even delivery of medical expenses. The methods of stimulating consumption by multiple parties have led to a steady growth of passenger flow in the early stage of the subway.
When entering the middle stage of development, the subway began to suffer huge losses. However, in fact, Nanjing is the only city in China that has made a profit in the metro, and the loss of the landfall system is also expected. In order to support the sustainable development of the metro industry, the subsidies provided by the government have played a significant role. In order to stimulate the use of the subway, the government has set up a public bicycle station near most of the subway stations, making it more convenient to reach the subway station and increase people's interest in the subway.
Mature phase
Judging from the current development trend of the Nanjing Metro, the Nanjing Metro is still in the development stage. The planning of the Nanjing Metro is from 2005 to 2030, and the subway system is not yet perfect. Currently, 10 subway lines are under construction at the same time
Optimization and improvement
* The ‘lock in’ of Nanjing Subway
Nanjing Metro is a state-owned company since its establishment and operates under the leadership of state-owned companies. In the government-led context, its capital is very stable, but it lacks the freedom of the market and restricts it. Its purpose is very strong, and the desire for profit is very low. Although a very large network system can be created, it also causes considerable capital wastage. Today, the subway system has experienced huge losses, but the government is still increasing investment and construction of the subway system. Subway is a kind of traffic mode that is not easy to change. Unlike road transport such as buses and bicycles, the embedded mode is rail transit and requires a lot of investment.
* ‘Re-invent’
The direction of the reinvent Nanjing subway should be to rationalize the use of the market, not only to meet the market demand, but also to obtain benefits and achieve a win-win situation. For the planning of the Nanjing Metro, we should first pay attention to quality, followed by quantity. Take care to combine existing models such as public transportation and public bicycles. Combination of multiple modes, clear division of labor, maximization of the characteristics of each mode of application: Metro through long-distance transportation within the city and ease the traffic pressure during peak times; bus for the transport of medium distance and bicycle can meet the short distance within the city Personal needs. This will reduce the waste of capital and maximize the utilization of the subway.

# Quantitative Analysis

'S'-Curve and Analysis
The method to analyze the data and S-Curve trend is based on the theory from GARRISON, W. L. and LEVINSON, D. M.
Year-Passengers(real & predicted) 2005-2017 :
| Year | Real Passengers Carried (thousands) | Predicted Passengers carried (thousands) |
| 2005 | 16210 | 28119 |
| 2006 | 57980 | 42295 |
| 2007 | 80160 | 63229 |
| 2008 | 103790 | 93677 |
| 2009 | 113530 | 137005 |
| 2010 | 214594 | 196777 |
| 2011 | 343701 | 275795 |
| 2012 | 400626 | 374578 |
| 2013 | 452160 | 489786 |
| 2014 | 503000 | 613758 |
| 2015 | 716540 | 736121 |
| 2016 | 830670 | 847020 |
| 2017 | 977410 | 940025 |
| Table 1. Nanjing Metro 2005-2017 Real/Predicted Passengers Carried |||
Among them, predicted passengers are calculated according to the following formula:
S(t) = K/[1+exp(-b(t-t0)]
where:
S(t) is the status measure (the predicted passengers e.g.)
t is time (years),
is the inflection time.
K is saturation status level,
b is a coefficient
* Determine K value
K is based on estimates of the 2005-2017 traffic growth. It is expected that passenger traffic will reach 1.19 billion passengers per year under saturated conditions. The initial value of k is chosen from 1100000 to 1300000. When the 1.19 billion of K value is taken, R square is closest to 1, the data analysis regression result is shown:
| k | 1120000 | 1130000 | 1140000 | 1150000 | 1160000 | 1170000 | 1180000 | 1190000 | 1200000 | 1210000 | 1220000 | 1230000 | 1240000 | 1250000 | 1260000 | 1270000 | 1280000 | 1290000 | 1300000 |
| R square | 0.972519 | 0.972973 | 0.973319 | 0.973576 | 0.973759 | 0.973878 | 0.973944 | 0.973964 | 0.973945 | 0.973893 | 0.973812 | 0.973706 | 0.973579 | 0.973434 | 0.973273 | 0.973098 | 0.972912 | 0.972716 | 0.97251 |
| Table 2. Finding K value ||||||||||||||||||||
* Regression result
| SUMMARY OUTPUT | SUMMARY OUTPUT | | | | | | | |
| Regression | Regression | | | | | | | |
| Multiple R | 0.986896001 | | | | | | | |
| R Square | 0.973963717 | | | | | | | |
| Adjusted R Square | 0.971596782 | | | | | | | |
| Standard Error | 0.279649049 | | | | | | | |
| Observation | 13 | | | | | | | |
| ANOVA | | | | | | | | |
| | df | SS | MS | F | Significance F | | | |
| Regression | 1 | 32.17978705 | 32.17979 | 411.4873 | 4.59104E-10 | | | |
| Residual | 11 | 0.860239498 | 0.078204 | | | | | |
| Total | 12 | 33.04002655 | | | | | | |
| | Coefficients | Standard Error | t Stat | P-value | Lower 95% | Upper 95% | Lower 95.0% | Upper 95.0% |
| Intercept | -846.8055342 | 41.68602411 | -20.3139 | 4.52E-10 | -938.5558546 | -755.0552137 | -938.555855 | -755.055214 |
| b | 0.42049021 | 0.020728967 | 20.28515 | 4.59E-10 | 0.374866062 | 0.466114358 | 0.374866062 | 0.466114358 |
| tnought: | 2013.85315 | | | | | | | |
| Table 3. Regression analysis when k = 1190000 |||||||||
* The S-Curve and analysis:
From the trend of the S curve, the Nanjing Metro should be in the end of growth phase. Current passenger traffic is in a period of rapid growth. From 2005 to 2009 is the birth phase of the Nanjing subway, and 2009 to 2017 is the growth phase of the Nanjing subway.
From the current S-curve trend, the development of the Nanjing Metro has reached the end of the growth phase. Compared with the expected value and the actual value, the degree of coincidence of the two is relatively high, which indicates that the future development is likely to follow the expected value. However, from the current traffic planning in Nanjing, there are 15 subway lines under planning. The metro is a more luxurious transportation mode for a city and is mainly used for transportation in the city center. However, the development direction of the Nanjing Metro began to tend to the surrounding areas of the main downtown area. Such traffic planning will increase the accessibility of the city, but on the whole it requires a lot of capital.

# Reference

* ↑ Henan TV. 中国地铁城市榜单发布 郑州排13超西安杭州 translated to EN [China's Metro Cities List Released, Zhengzhou Ranked 13th and Exceeded Xi'an and Hangzhou] [10.05.2018]
* ↑ Bendibao. Nanjing Metro. [10.05.2018]
* ↑ Sina Watch Point. 内地十大城市地铁排名——从通车里程和地铁密度看城市综合实力 translate to EN [China's Metro Cities List Released, Zhengzhou Ranked 13th and Exceeded Xi'an Hangzhou] [10.05.2018]
* ↑ 2017年度中国十大城市地铁总客流量盘点！ translate to EN [The total subway traffic volume of the top ten cities in China in 2017 is counted!] [10.05.2018]
* ↑ 踏青季-南京地铁客流创新高 translate to EN [Travel season - Nanjing subway passenger flow innovation high] [10.05.2018]
* ↑ 2018年3月南京地铁客流统计数据 translate to EN [Nanjing Metro passenger flow statistics in March 2018] [10.05.2018]
* ↑ 近十年南京地铁建设顺序是这样的！4号线2期呢？ translate to EN [The order of Nanjing subway construction in the past ten years is like this! What about Line 4?] [10.05.2018]
* ↑ Nanjing Price Bureau. 关于制定南京地铁线网票价的通知 translate to EN [Notice on Establishing Nanjing Metro Line Network Tickets] [10.05.2018]
* ↑ Sohu News. 南京公交等车时间创七年之最 客流比非典年还少 Translate to EN [Nanjing bus waited for the most seven-year passenger flow time less than the SARS period] [10.05.2018]
* ↑ Statistics Bureau of Jiangsu Province. 改革开放以来南京市人口、家庭结构变化分析 translate to EN [An Analysis of the Changes of Population and Family Structure in Nanjing since the Reform and Opening-up] [10.05.2018]
* ↑ Nanjing Traffic Institute. 2007年南京交通发展年度报告 translate to EN [Annual Report on Nanjing Traffic Development in 2007] [10.05.2018]
* ↑ http://www.nanjing.gov.cn/xxgk/bm/zwb/201704/t20170405_4423692.html
* ↑ Nanjing Municipal People's Government. 关于尽快推进地铁运营成本规制工作的建议 translate to EN [Suggestions on Promoting Subway Operation Cost Regulation as Fast as Possible] [10.05.2018]
* ↑ “10线同建”，见证不一样的轨交时刻；2018，南京地铁持续发力！ translate to EN ["10 lines with the construction of" witnessed a different track time; 2018, Nanjing subway continues to force!] [10.05.2018]
* ↑ Garrison, W. and Levinson, D. (2014). The Transportation Experience. Oxford: Oxford University Press, USA.
* ↑ Statistics Bureau of Jiangsu Province. 江苏城市轨道交通发展分析 translate to EN [Analysis of Development of Urban Rail Transit in Jiangsu] [10.05.2018]
* ↑ DanYing S. 南京地铁运营里程世界排名11 translate to EN [Nanjing Metro mileage ranking 11] [10.05.2018]
* ↑ Yan G. 南京地铁日均客流110万人次 满意度居全国前列 translate to EN [Nanjing's daily passenger flow 1.1 million passengers satisfaction ranks in the forefront of the nation] [10.05.2018]
* ↑ Nanjing Subway News. 南京地铁概况_南京地铁简介 translate to EN [Nanjing Metro Introduction] [10.05.2018]