Time sharing between activities remains an indispensable part of everyday activity pattern. However, the issue has not yet been fully acknowledged within the existing time allocation models, potentially resulting in inaccuracies in valuing travel time savings. Therefore this study is aimed at addressing this gap by investigating the potential impact of introducing time sharing within such a framework, as well as factors determining it as represented by travel activities. In doing so, time constraint in the time allocation model of Small was modified to enable sharing the same time interval between different activities. The resulting expression indicated that such an augmentation could lead to lower estimates of value of time as a resource. On the other hand, empirical research based on the data from the National Passenger Survey 2004 used for calibrating cross-nested logit model indicated a number of factors affecting the choice of travel activities. It was discovered that significant include possession of equipment allowing particular activities, e.g. newspaper, paperwork or ICT devices, companionship, gender, length of the journey, frequency of using the service, possibility of working on the train, journey planning in advance, first class travel, termination of the trip in central London, peak-time travel and availability of seating.

翻译：活动间的时间共享仍是日常活动模式中不可或缺的组成部分。然而，现有时间分配模型尚未充分认识这一问题，可能导致对旅行时间节省价值的评估存在偏差。因此，本研究旨在通过探讨在此类框架中引入时间共享的潜在影响及其决定因素（以旅行活动为表征）来填补这一空白。为此，本研究对Small时间分配模型中的时间约束条件进行了修正，使其允许不同活动共享同一时间段。推导结果表明，此种扩展可能导致作为资源的时间价值估值降低。另一方面，基于用于标定交叉嵌套Logit模型的2004年全国乘客调查数据开展的实证研究，揭示了影响旅行活动选择的若干因素。研究发现，显著影响因素包括：允许进行特定活动（如阅读报纸、处理文书工作或使用信息通信技术设备）的装备持有情况、同行人员、性别、旅程长度、服务使用频率、火车上工作的可能性、提前规划行程、乘坐头等车厢、行程终点位于伦敦市中心、高峰时段出行以及座位可得性。