Travel time reliability is the key aspect that indicates the quality of urban public transit service. The studies on travel time reliability of the public transit system in Indian traffic conditions are few. Also, the impact of side friction elements on travel time reliability has not been considered in the previous studies. Hence, the present study aims to quantify the different types of side friction elements and analyse their impact on the travel time reliability of the public bus transit system. The field data consisting of side friction elements, traffic volume, and travel time of public bus transit have been collected and extracted at two different road sections (divided and undivided) in the Mysore city (Karnataka, India) during weekdays and weekends. The data are grouped into static and dynamic side frictions. An approach has been proposed to represent different types of side friction elements with a single index called the Side Friction Index (SFI) using relative weight analysis. Travel time reliability is represented using measures such as Buffer Time Index (BTI), Planning Time Index (PTI), Travel Time Index (TTI) and Reliable Buffer Index (RBI). The impact of side friction on travel time reliability was found to be sensitive to traffic volume, and hence the thresholds for different traffic volume levels have been determined using K-means clustering method. It was observed from relative weight analysis that the static side friction has a higher weightage (0.509 and 0.327 for the undivided road and divided road respectively) than the dynamic side friction elements in describing the variation of travel time. The impact of side friction on reliability measures at different traffic volume levels has been studied and found to have a non-linear (exponential) relationship. The impact of SFI has been observed to be higher on TTI and PTI in comparison with BTI. The study outcomes show that the impact of side friction on TTI and PTI is sensitive to traffic volume, especially at higher traffic volume level and impact of side friction on BTI is less, especially at medium traffic volume level. The inference from the study shows that the impact of side friction elements varies with respect to the type of road (divided and undivided), traffic volume levels, different days of week (weekday and weekend), and different time periods of day.

出行时间的可靠性是指示城市公共交通服务质量的关键方面。在印度交通状况下，对公共交通系统的出行时间可靠性的研究很少。同样，在先前的研究中未考虑侧面摩擦元件对行程时间可靠性的影响。因此，本研究旨在量化侧向摩擦元件的不同类型，并分析它们对公共交通系统行驶时间可靠性的影响。在工作日和周末，在迈索尔市（印度卡纳塔克邦）的两个不同路段（划分和未划分）收集并提取了由侧面摩擦元素，交通量和公交车行驶时间组成的现场数据。数据分为静态和动态侧向摩擦。已经提出了一种方法，该方法使用相对重量分析用一个称为侧向摩擦指数（SFI）的单一指数来表示不同类型的侧向摩擦元件。使用诸如缓冲时间指数（BTI），计划时间指数（PTI），行驶时间指数（TTI）和可靠缓冲指数（RBI）之类的度量来表示行驶时间的可靠性。发现侧面摩擦对行驶时间可靠性的影响对交通量敏感，因此，使用以下方法确定了不同交通量水平的阈值ķ-均值聚类方法。从相对重量分析中可以看出，在描述行驶时间变化时，静态侧摩擦具有比动态侧摩擦元件更高的权重（分别为0.509和0.327）。研究了侧面摩擦对不同交通量水平下可靠性度量的影响，并发现它们之间具有非线性（指数）关系。与BTI相比，已观察到SFI对TTI和PTI的影响更大。研究结果表明，侧面摩擦对TTI和PTI的影响对交通量敏感，尤其是在较高交通量水平下，而侧面摩擦对BTI的影响则较小，尤其是在中等交通量水平下。