Naoki Shibahara

Estimating Additional Mass Transit Needed to Reduce Carbon Dioxide Emissions from Regional Passenger Transport in Japan

This study aims to estimate the necessary scale of additional mass transit on trunk lines to reduce carbon dioxide (CO2) emissions from regional passenger transport in Japan. First, a local transport region is defined as an area within which most daily transport is conducted. In each region, the target of CO2 emissions from local passenger transport activities in 2050 is set to 20% of those emissions in 2000. The amount of CO2 exhaust from local passenger transport can be estimated on the basis of technological innovation; thus, the amount of reduction needed to achieve the target can be calculated. Second, changes in CO2 emissions from the introduction of a mass transit system are evaluated, considering their reduction from replacing private vehicles and the emissions from constructing and operating the mass transit system. For this purpose, life-cycle assessment is applied. The total amount of CO2 emissions from infrastructure construction, vehicle production, and operation from mass transit is calculated. The transport density of each route is estimated with population density in a densely inhabited district of each local transport region. The transit system that emits the least CO2 per passenger kilometer is selected. The extent of new services needed to achieve the CO2 reduction target is calculated. A series of calculations provides the lengths of additional mass transit routes required to reduce traffic volumes sufficiently to achieve the CO2 reduction target for local passenger transport by 2050.

A Study for the Measurement of Environmental Impact Resulting From Railway Construction

This study shows how to measure CO2 emissions caused by railways during its life span from construction to disposal. It is now a common global concern that CO2 reduction is vital for conserving the global environment. Amidst this growing awareness, rail transport has attracted significant attention as an environmentally-friendly transportation mode due to its low emission of CO2 gas. But in many studies the amount of CO2 is calculated only during operation and doesn’t include emissions during the phase of construction of related infrastructure and rolling stocks. Rail transport can not be a truly environmentally-friendly transportation mode if it isn’t proven to emit less gases compared with other modes during a modes whole life cycle. In this paper, we introduce the method to calculate CO2 emission from the construction of infrastructure with the application of Life Cycle Assessment (LCA) and the result of a case study.Copyright

Methodology for Identifying an Inter-regional Passenger Transport System Generating Less Carbon Dioxide

40 Vol.5 No.1 January 2009 1. 序論 2006年における日本の人為起源CO2総排出量に占める 旅客交通起源排出量の割合は12.0%である。そのうち航空 は6.2%(総排出量の0.8%)を占めているが、1990年比で 60.9%増と著しい増加を示している。また、運輸部門のう ちで脱炭素燃料に切り替わるのが最も遅いのは航空産業と 考えられており、航空からのCO2排出量割合が他部門に比 べ相対的に上昇していく要因として懸念される1)。 欧州では、航空会社のETS(European Emission Trading Scheme: 欧州排出権取引市場)への参加や、運航によっ て排出されたCO2の削減費用の一部を搭乗客に負担しても らい、排出を埋め合わせするカーボン・オフセットの普及 など、地球温暖化防止を重視した取り組みが実施に移され つつある。それとともに、地域間高速鉄道網の整備や高速 道路通行への課金といった施策も推進されている。日本に おいても今後は、導入・充実すべき輸送モードを環境性能 Synopsis: Objective. The focus of carbon dioxide (CO2) emissions reduction policies for the inter-regional passenger transport system depends on two factors: 1) the aviation sector is the slowest to eliminate use of carbon fuels; and 2) aviation is expected to contribute more to greenhouse gas emissions than other transport modes. Therefore, the purpose of this study is to explore the possible changes in each indicator of Life Cycle CO2 (LCCO2) per passenger-km and eco-efficiency considering travel speed as a result of a shift from aviation to the high speed railway system (Shinkansen). CO2 emissions both for aviation and Shinkansen were estimated by applying the Life Cycle Assessment (LCA) method and taking into account same important parameters such as passenger demand. Results and Discussion. CO2 exhausted from aviation and Shinkansen during normal operation and the additional LC-CO2 from new infrastructure provision were compared. The first analyzed the sensitivity with regard to the number of passengers for a 500km long corridor. The results indicate the following: 1) CO2 per passenger-km generated from aviation hardly vary with the number of passengers; 2) LC-CO2 per passenger-km for Shinkansen is inversely proportional to the number of passengers; 3) LC-CO2 per passenger-km for Shinkansen is lower than that for aviation for the passenger volume of approximately 1,200 or more passengers per day; and 4) for eco-efficiency, the break-even point is more than around 2,000 passengers per day. The second considers the distance and travel demand for both aviation and Shinkansen. A possible shift from the current demand for aviation to Shinkansen was compared for each inter-prefectural Origin-Destination (OD) pair. Shinkansen was found to be superior for OD pairs with higher demand and shorter distances. Conclusions. This paper proposed a methodology for identifying an inter-regional transport system with lower CO2 emissions. An application to the inter-prefectural ODs for existing airlines in Japan shows the conditions that provide an advantage of lower CO2 emissions for aviation or Shinkansen.

Life Cycle Assessment Approach on Impacts of Road Improvement Projects Considering Effects of Traffic Flow: Case Study for Removal of a Railway Crossing

33 Vol.5 No.1 January 2009 1. はじめに 自動車交通は地球温暖化をはじめとする環境問題の大き な要因であり、環境負荷削減の立場からの対策が急がれて いる。自動車交通起源の環境負荷排出量を削減する手段は、 大きくa)自動車総走行量の削減、b)1台当たり排出量の 削減に分けることができる。そのうちb)は、自動車単体 燃費の向上はもとより、走行状況の改善による実走行燃費 の改善が有効である。自動車走行は、渋滞や交差点・踏切 の存在によってストップ・アンド・ゴーやアイドリング時 間が多くなると、燃費が悪化し環境負荷発生が増大するこ とから、走行状況の改善が効果的な環境負荷削減施策にな りうる。そのため、渋滞解消とそれに伴う環境負荷削減に 関する分析が数多く行われている。 国土交通省道路局では2006年度以降、地球温暖化防止 のための道路政策として「CO2削減アクションプログラム」 を推進している。これは、主要渋滞ポイント対策、環状道 路整備、ITSの活用促進等によって走行環境を改善しCO2 排出量削減を図るものである。特に交通円滑化施策は約6.5 ~ 7.0[Mt-CO2/年]の削減効果が見込まれており、主要な 施策と位置付けられている。施策の具体的な内容として、 高速道路の利用促進と並んで、交差点改良や踏切除却、車 道拡幅等による渋滞箇所解消のための道路改良事業が挙げ られている。 しかしながら、これらの事業は大規模なインフラ整備を 必要とするため、コストも大きくなり、かつインフラ建設 自体に伴う環境負荷排出も大きい。国土交通省や建設会社 Synopsis: Objective. Road traffic contributes significantly to carbon dioxide (CO2) emissions. Road improvement projects are one of the effective measures to reduce CO2 emissions. In this study, a methodology based on the Life Cycle Assessment (LCA) approach is developed for evaluating environmental impacts of road improvement projects. Results and Discussion. A framework for evaluating environmental loads from road transport system including road infrastructure and vehicle traveling is proposed. The framework also enables us to analyze changes in driving conditions that are influenced by road improvement. Further, it evaluates the impacts due to induced traffic and change in traffic speed. The method is applied to a road improvement projects involving removal of a railway crossing by constructing an elevated track. A project undertaken in this study can reduce System Life Cycle CO2 (SyLC-CO2) because it improves driving conditions by reducing stops and congestion due to railroad crossing. However, sensitivity analysis shows the following important findings: 1) SyLC-CO2 increases if traffic volume increases by more than 1.28 times after the project; 2) For a crossing where the traffic volume is less than 3,000 vehicles, such a project is unsuitable because the SyLC-CO2 increases after the project; 3) Large traffic volume is not required to reduce SyLC-CO2 if the crossing is closed long times. Conclusions. The results of a sensitivity analysis carried out under different traffic conditions indicate that there is an overall decrease in CO2 emissions because, despite improvements in driving conditions, the environmental load contributed by road traffic is greater than the total load contributed by infrastructure construction and induced traffic.