Greater Manchester Travel Diary Survey 2022 - district summaries

Each year, the Greater Manchester Travel Diary Survey (TRADS) collects transport and travel information from every member (aged over four) of 2,000 households; respondents provide details about all the trips they make in a 24-hour period. TRADS is not an attitudinal survey, its focus is on the details of the trips and the characteristics of the people who make those trips.

The survey sample is designed so that each GM district is represented proportionately, based upon the demographics of the resident population. The survey programme covers the duration of a full year; surveys are in-field every day, excluding Christmas Day and any days after a bank holiday. The fieldwork period starts at the beginning of February and finishes at the end of the following January.

The data collected from 2,000 GM households equates to about 4,500 residents and between 7,000 and 10,000 trips. The survey collects information about trips including origins and destinations, travel times, method of travel used and journey purpose.

Prior to the pandemic our trip estimates were based on data collected over a three-year period, which provided confidence intervals of +/- 1% at the GM household level. At the district household-level the confidence intervals were +/- 3% to 4%. This was possible as people’s travel habits were relatively stable over the short-term. However, since the start of the pandemic in 2020, people’s travel habits have not been stable enough for this approach to be used, so our estimates are based on survey data from a single year.

The data is weighted/expanded to the GM population, based on district population by age and gender as well as Acorn Category. The survey weights are small, and the weighting efficiency is high. The weighting/expansion methodology from TRADS changed between 2019 and 2022 to better account for population growth. In 2019s TRADS data the population size for each district was expanded to the level recorded in the Census 2011. However, the data for 2022 is expanded to the 2021 mid-year population estimates (the latest estimate available at the time of weighting). This change has impacted some districts, like Manchester and Salford, more than others. The main impact is that in areas with significant population growth the estimated number of trips has increased despite the average trip rate per person decreasing.

The survey is delivered by a team of experienced interviewers who conduct face-to-face interviews. Prior to the pandemic the response rate was typically 50-60%. During the pandemic the survey methodology changed to a mixed methodology of recruitment via letter and interviews being conducted via telephone. This saw the response rate drop significantly. As restrictions on socialising eased, a mixed methodology of letter/phone and face-to-face was used, finally moving back to face-to-face interviewing in August 2021. The overall response rate in 2021 was 19%, but the response rate for face-to-face interviews was 43%.

The data include in this report includes estimates for the years 2019 and 2022. While the overall estimates at the district household-level have confidence intervals of +/- 8% to 7%, caution should be used when interpreting the sub-group estimates of commute trips, short-trips, age, and by hour and purpose. The confidence intervals around these estimates are much larger and the findings should be treated as indicative.

Where totals in tables don't sum to the figures in the table it is because the estimates are rounded to the nearest 1,000.

每年，大曼彻斯特旅行日记调查（TRADS）从2,000户家庭的每一位（年龄超过四岁）成员处收集交通和旅行信息；受访者需提供他们在24小时期间所进行的所有旅行的详细信息。TRADS并非一项态度调查，其关注点在于旅行的细节以及进行这些旅行的人们的特征。

调查样本设计旨在确保每个大曼彻斯特地区均按居民人口统计学比例得到代表。调查项目覆盖整整一年；调查每天都在进行，除了圣诞节和任何公共假日之后的日期。实地调查期始于二月初，结束于次年一月底。

从2,000户大曼彻斯特家庭收集的数据相当于约4,500名居民以及7,000至10,000次旅行。调查收集有关旅行的信息，包括出发地和目的地、旅行时间、使用的旅行方式和旅行目的。

在大流行病之前，我们的旅行估计是基于为期三年的数据收集，在大曼彻斯特家庭层面提供了±1%的置信区间。在地区家庭层面，置信区间为±3%至4%。这是可能的，因为人们的旅行习惯在短期内相对稳定。然而，自2020年大流行病开始以来，人们的旅行习惯已经不稳定到无法采用这种方法，因此我们的估计基于一年的调查数据。

数据根据地区人口、年龄和性别以及Acorn类别对大曼彻斯特人口进行了加权/扩展。调查权重较小，加权效率较高。TRADS的加权/扩展方法在2019年至2022年之间发生了变化，以更好地反映人口增长。2019年的TRADS数据中，每个地区的总人口规模扩展到2011年人口普查中记录的水平。然而，2022年的数据扩展到2021年中期人口估计（当时可用的最新估计）。这一变化对某些地区（如曼彻斯特和索尔福德）的影响大于其他地区。主要影响是，在人口增长显著的地区，尽管每人平均旅行率有所下降，但估计的旅行次数却有所增加。

调查由一支经验丰富的访谈员团队执行，他们进行面对面访谈。在大流行病之前，响应率通常为50-60%。在大流行期间，调查方法改为通过信件招募和电话访谈的混合方法。这导致响应率显著下降。随着社交限制的放宽，采用了信件/电话和面对面的混合方法，最终于2021年8月恢复面对面访谈。2021年的总体响应率为19%，但面对面访谈的响应率为43%。

本报告中的数据包括2019年和2022年的估计值。尽管地区家庭层面的总体估计置信区间为±8%至7%，但在解释通勤旅行、短途旅行、年龄以及按小时和目的的子组估计时，应谨慎行事。这些估计的置信区间要大得多，且发现应被视为指示性的。

当表格中的总计与表中数字不符时，是因为估计值已四舍五入到最接近的1,000。