Brand Christian, Goodman Anna, Ogilvie David
Environmental Change Institute, University of Oxford, Oxford, United Kingdom.
Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK (
Appl Energy. 2014 Sep 1;128:284-295. doi: 10.1016/j.apenergy.2014.04.072.
Walking and cycling is widely assumed to substitute for at least some motorized travel and thereby reduce energy use and carbon dioxide (CO) emissions. While the evidence suggests that a supportive built environment may be needed to promote walking and cycling, it is unclear whether and how interventions in the built environment that attract walkers and cyclists may reduce transport CO emissions. Our aim was therefore to evaluate the effects of providing new infrastructure for walking and cycling on CO emissions from motorised travel. A cohort of 1849 adults completed questionnaires at baseline (2010) and one-year follow-up (2011), before and after the construction of new high-quality routes provided as part of the Sustrans Connect2 programme in three UK municipalities. A second cohort of 1510 adults completed questionnaires at baseline and two-year follow-up (2012). The participants reported their past-week travel behaviour and car characteristics from which CO emissions by mode and purpose were derived using methods described previously. A set of exposure measures of proximity to and use of the new routes were derived. Overall transport CO emissions decreased slightly over the study period, consistent with a secular trend in the case study regions. As found previously the new infrastructure was well used at one- and two-year follow-up, and was associated with population-level increases in walking, cycling and physical activity at two-year follow-up. However, these effects did not translate into sizeable CO effects as neither living near the infrastructure nor using it predicted changes in CO emissions from motorised travel, either overall or disaggregated by journey purpose. This lack of a discernible effect on travel CO emissions are consistent with an interpretation that some of those living nearer the infrastructure may simply have changed where they walked or cycled, while others may have walked or cycled more but few, if any, may have substituted active for motorised modes of travel as a result of the interventions. While the findings to date cannot exclude the possibility of small effects of the new routes on CO emissions, a more comprehensive approach of a higher 'dosage' of active travel promotion linked with policies targeted at mode shift away from private motorized transport (such as urban car restraint and parking pricing, car sharing/pooling for travel to work, integrating bike sharing into public transport system) may be needed to achieve the substantial CO savings needed to meet climate change mitigation and energy security goals.
人们普遍认为，步行和骑自行车至少能替代部分机动化出行，从而减少能源消耗和二氧化碳（CO₂）排放。虽然有证据表明，可能需要一个支持性的建成环境来促进步行和骑自行车，但尚不清楚吸引步行者和骑车者的建成环境干预措施是否以及如何能减少交通领域的CO₂排放。因此，我们的目标是评估提供步行和自行车新基础设施对机动化出行的CO₂排放的影响。在英国三个城市作为“可持续交通连接2”（Sustrans Connect2）项目一部分新建高质量路线建设之前和之后，一组1849名成年人在基线期（2010年）和一年随访期（2011年）完成了问卷调查。另一组1510名成年人在基线期和两年随访期（2012年）完成了问卷调查。参与者报告了他们过去一周的出行行为和汽车特征，据此使用先前描述的方法得出不同出行方式和出行目的的CO₂排放量。得出了一系列关于新路线的接近程度和使用情况的暴露指标。在研究期间，总体交通领域的CO₂排放略有下降，这与案例研究地区的长期趋势一致。如之前所发现的，新基础设施在一年和两年随访期得到了充分利用，并且在两年随访期与人口层面的步行、骑自行车和身体活动增加有关。然而，这些影响并没有转化为可观的CO₂减排效果，因为无论是住在基础设施附近还是使用它，都无法预测机动化出行的CO₂排放量的变化，无论是总体上还是按出行目的分类。对出行CO₂排放缺乏明显影响，这与一种解释一致，即一些住在基础设施附近的人可能只是改变了他们步行或骑车的地点，而另一些人可能步行或骑车更多了，但由于这些干预措施，很少有人（如果有的话）可能用主动出行方式替代了机动化出行方式。虽然迄今为止的研究结果不能排除新路线对CO₂排放有微小影响的可能性，但可能需要一种更全面的方法，即加大“剂量”推广主动出行，并结合旨在促使出行方式从私人机动化交通转变的政策（如城市汽车限制和停车定价、上班拼车/拼车出行、将共享单车纳入公共交通系统），以实现为应对气候变化缓解和能源安全目标所需的大幅CO₂减排。
