## 4 Discussion
**Major finding B-2**: the finding that \(\mathbf{L_{UCF}}\) was evaluated as inferior to \(\mathbf{L_{LCF}}\) and \(\mathbf{L_{CC}}\) can be explained by the increased physical strain imposed on drivers when the gearshift is positioned at \(\mathbf{L_{UCF}}\), requiring them to raise and extend their arm for gear shifting. In this regard, comments such as 'it is preferable because of the easy-to-reach location' and 'it is comfortable because the gearshift is reachable with the arm lowered in a natural position' were exclusively collected for \(\mathbf{L_{LCF}}\) and \(\mathbf{L_{CC}}\). The findings from the freehand design session (Table 8) further support this, as only 1 out of the 43 collected pictures featured the gearshift in \(\mathbf{L_{UCF}}\), indicating that \(\mathbf{L_{UCF}}\) is a non-preferred location. Relatedly, some design guidelines for in-vehicle controls also recommend placing controls in easily reachable locations by the driver's hand [29]; additionally, empirical evidence has demonstrated that as the target distance and height from the driver's seat increase, driver discomfort also increases [46]. The inferiority of \(\mathbf{L_{UCF}}\) could also be interpreted in that the driver's actions for using the gearshift in this location (e.g., reaching out for or operating the gearshift) could visually obstruct the information provided through the in-vehicle information system (IVIS) typically located in \(\mathbf{L_{UCF}}\). This interpretation aligns with design recommendations for IVIS that in-vehicle controls should be located so that the driver's hand does not block the view of an in-vehicle display [47]. As a promising alternative that reduces the physical strain imposed and avoids the visual obstruction of IVIS, the 'near the steering wheel' location, as adopted by Porsche (Table 1), may be suggested. The freehand design session results (Table 8) also indicate a preference for this location, as all eight pictures with the gearshift placed at the location not considered in this study featured the gearshift near (on the left or right side of) the steering wheel. Considering that the 'near the steering wheel' location also reduces the driver's eye and hand movement during driving, which is an aspect crucial for lowering the risk of road traffic accidents [16; 19; 20], further investigation into its effectiveness is warranted. **Major finding C-1**: the finding that when the in-vehicle location was \(\mathbf{L_{CC}}\), \(\mathbf{M_{LS}}\) was evaluated superior to \(\mathbf{M_{BP}}\) and \(\mathbf{M_{DR}}\), and when the operation method was \(\mathbf{M_{LS}}\), \(\mathbf{L_{CC}}\) was evaluated superior to \(\mathbf{L_{LCF}}\) can be attributed to the widespread adoption of the combination of \(\mathbf{M_{LS}}\) and \(\mathbf{L_{CC}}\) (i.e., \(\mathbf{M_{LS}}\)\(\mathbf{L_{CC}}\)) in gearshift designs by many automotive manufacturers over several decades. In other words, it seems that \(\mathbf{M_{LS}}\)\(\mathbf{L_{CC}}\) has become the most familiar combination for drivers, leading to the most favorable evaluations. Indeed, \(\mathbf{M_{LS}}\)\(\mathbf{L_{CC}}\) was the most frequently collected picture (9 out of 43, 20.9%) from the freehand design session, with mentions of reasons such as'seeking a familiar operation method and in-vehicle location'. This aligns with the general design principle that consistently placing the same items in the same locations induces instinctive and automatic human behaviors [36]. However, it is essential to note that this perceived superiority might result from accessibility bias, a phenomenon that researchers generally believe should be approached with caution [48; 49; 50]. Consequently, careful and empirical examination is required to determine whether the design of this \(\mathbf{M_{LS}}\)\(\mathbf{L_{CC}}\) combination best serves driving performance and safety. **Major finding C-2**: the finding that when the in-vehicle location was \(\mathbf{L_{RWS}}\), \(\mathbf{M_{LS}}\) was evaluated inferior to \(\mathbf{M_{BP}}\) can be explained in several ways.