摘要: |
非机动出行和公共交通出行通常被认为相较于驾车出行是更低碳的出行方式。本文基于这一背景提出一种城市低碳出行潜力的分级评估方法。该方法将可能转变为非机动出行的机动出行人群在全部出行人群中的数量占比定义为城市交通一级低碳出行潜力,将可能转变为公共交通出行的驾车出行人群在全部出行人群中的数量占比定义为城市交通二级低碳出行潜力,从而整体呈现城市在控制交通碳排放方面的可进步空间。该方法考虑距离是非机动出行较之于机动出行的主要不利因素而影响居民非机动出行意愿,接驳、绕行、换乘是公共交通出行较之于驾车出行的主要不利因素而影响居民公共交通出行意愿,从而通过对居民实际出行距离以及公共交通出行模式下实际接驳、绕行、换乘强度值与假定居民最大可接受出行距离以及最大可接受接驳、绕行、换乘强度值的比较,识别假定场景中可能转变为相应等级低碳出行的人群数量并据此计算相应的低碳出行潜力值,然后进一步分析其值随居民对于非机动出行可接受距离以及公共交通出行可接受接驳、绕行、换乘强度阈值变化的趋势并拟合其关系曲线,发现拟合曲线呈现反向“S”型态,由此识别了曲线的“快速变化区”及“关键点”。本文以中国上海市及武汉市为例,基于19,732份居民日常出行OD调查样本对两个城市的低碳出行潜力进行了分级评估,由此分析了两个城市的低碳出行潜力特征并比较了两个城市的低碳出行潜力差异。 |
关键词: 低碳出行潜力 非机动出行 公共交通 接驳 绕行 换乘 |
DOI: |
分类号:U4 |
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目), |
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Stratified Assessment of Urban Low-Carbon Travel Potential and Analysis of Influencing Factors: A Case Study of Two Chinese Cities |
Peng Ran,Ding Keyuan,Liu Feiyang
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Abstract: |
Urban transportation systems have a substantial potential for carbon emission reduction, particularly through promoting low-carbon travel modes such as non-motorized travel (e.g., walking and cycling) and public transportation. Compared to car travel, these modes not only reduce carbon emissions but also contribute positively to overall urban air quality and resident health. Based on this context, this paper develops a novel stratified assessment framework for urban low-carbon travel potential, introducing two distinct levels of assessment. The first level, termed “Tier 1 low-carbon travel potential,” represents the proportion of current motorized travelers who could realistically shift to non-motorized travel modes. The second level, “Tier 2 low-carbon travel potential,” indicates the proportion of car travelers who might switch to public transportation, thus providing a multi-layered approach for gauging cities’ carbon reduction opportunities within their transportation systems.
This study hypothesizes that distance is the primary limiting factor affecting residents' willingness to engage in non-motorized travel over motorized travel, while factors such as connection convenience, detour requirements, and transfer intensity hinder public transportation use in favor of car travel. Therefore, this study defines quantitative parameters, including maximum acceptable distance for non-motorized travel and maximum acceptable strengths for public transportation connection, detour, and transfer. By comparing actual resident travel distances and intensities under these parameters in hypothetical scenarios, the study identifies and quantifies the populations in Shanghai and Wuhan that could potentially shift to each low-carbon travel tier.
Further analysis examines trends in these potential shifts in relation to changes in residents' acceptable thresholds for non-motorized distance and public transportation intensities. The relationship curves reveal an inverse "S"-shaped trend, with identified "rapid change zones" and "critical points" where low-carbon travel potential undergoes significant shifts. Using Shanghai and Wuhan as case studies, the paper calculates the low-carbon travel potential for both cities, providing a graded and nuanced assessment that highlights specific characteristics of low-carbon travel potential and compares the differences between these two major Chinese cities.
In terms of methodology, the research draws on 19,732 daily travel Origin-Destination (OD) survey samples from residents of Shanghai and Wuhan. These cities were chosen for their distinct geographical and infrastructural features: Shanghai, with its dense urban population and extensive public transportation network, serves as a prime example of a highly developed transportation system. In contrast, Wuhan, known for its unique geography with intersecting rivers and numerous lakes, presents a case where natural barriers pose unique challenges for urban transportation development.
To calculate potential low-carbon travel mode shifts, the study defines several key metrics based on OD data, such as the Non-motorized Travel Strength (S_n) for walking or cycling trips and various Public Transportation Strength, including Connection Strength (S_c), Detour Strength (S_d), and Transfer Strength (S_t). NTS is defined as the total distance traveled between origin and destination points via non-motorized means, while Public Transportation Strength metrics are calculated based on distances related to walking connections, route detours, and transfers encountered within public transportation networks. These metrics help quantify the feasibility of residents switching to low-carbon travel based on various city-specific scenarios.
The assessment approach introduces two classification levels for potential low-carbon travelers. In Tier 1, individuals are classified based on their maximum acceptable distance for non-motorized travel, allowing a distinction between residents who currently use motorized transport but could feasibly shift to walking or cycling. Tier 2 further differentiates travelers by considering public transportation as a lower-carbon alternative to car travel, using maximum acceptable strengths for S_c, S_d, and S_t. The stratified classification includes both "Active" and "Passive" low-carbon travelers within each tier, representing individuals who are either already engaging in low-carbon travel or could be encouraged to shift under the right conditions.
The results of this analysis indicate that both cities exhibit significant low-carbon travel potential, although Shanghai's potential generally surpasses that of Wuhan. Specifically, Shanghai shows a higher Tier 1 potential due to its developed non-motorized travel infrastructure, while its Tier 2 potential also outpaces Wuhan’s due to a higher proportion of car users. The comparative curve analysis shows that Shanghai's and Wuhan’s Tier 1 potential curves nearly converge at higher thresholds, indicating similar travel behavior once non-motorized distances reach approximately 10 km. However, for Tier 2 potential, significant differences emerge based on connection and detour factors, with Shanghai residents displaying a higher tolerance for transfers and detours.
The findings underscore specific areas for urban policy intervention. For Tier 1, enhancing the walking and cycling infrastructure within rapid change zones can potentially increase the proportion of residents who shift from motorized travel to non-motorized modes, thus maximizing carbon reduction potential. For Tier 2, optimizing public transportation accessibility—particularly by reducing transfer and detour requirements—can increase the attractiveness of public transportation as a viable alternative to car travel, with both Shanghai and Wuhan benefiting significantly.
The study concludes that urban low-carbon travel potential follows an inverse “S”-shaped pattern, with key thresholds where strategic interventions may lead to substantial reductions in urban carbon emissions. The graded assessment approach provides urban planners with a practical framework to identify rapid change zones and prioritize specific infrastructural improvements to support low-carbon travel adoption. This research has significant implications for cities seeking to reduce carbon emissions through more efficient and sustainable urban transportation policies. |
Key words: low-carbon travel potential non-motorized travel public transportation connection detour transfer |