## 3 Results
### Interaction Effects between the Operation Method and In-Vehicle Location  
The ANOVA results indicated that the interaction effects between the operation method and in-vehicle location were statistically significant for all nine measures: accuracy \(F(8,\,312)=3.46,\,p<0.01\); efficiency \(F(8,\,312)=2.65,\,p<0.05\); rapidity \(F(8,\,312)=2.51\), \(p<0.05\); learnability \(F(8,\,312)=3.50,\,p<0.01\); intuitiveness \(F(8,\,312)=2.50,\,p<0.05\); safety \(F(8,\,312)=2.58,\,p<0.05\); preference \(F(8,\,312)=2.45,\,p<0.05\); memorability  
Figure 3: The main effects of the in-vehicle location (mean [standard deviation] values of each in-vehicle location for each measure): (**a**) accuracy, (**b**) efficiency, (**c**) rapidity, (**d**) learnability, (**e**) intuitiveness, (**f**) safety, (**g**) preference, (**h**) memorability, and (**i**) satisfaction. \(F(5.76,224)=2.53\), \(p<0.05\); and satisfaction \(F(5.66,220)=3.05\), \(p<0.01\). The mean and standard deviation values of each combination of operation method and in-vehicle location (i.e., design alternative) for each dependent measure are shown in Figure 4, with asterisks indicating the significant simple main effects. The statistically significant simple main effects of the operation method are as follows:  
* When the in-vehicle location was \(\mathbf{L_{RWS}}\),
* \(\mathbf{M_{LS}}\) showed significantly higher mean scores than \(\mathbf{M_{DR}}\) in rapidity and memorability. * \(\mathbf{M_{BP}}\) exhibited significantly higher mean scores than (1) \(\mathbf{M_{LS}}\) in satisfaction and (2) \(\mathbf{M_{DR}}\) across all nine measures. * When the in-vehicle location was \(\mathbf{L_{UCF}}\),
* \(\mathbf{M_{BP}}\) showed significantly higher mean scores than \(\mathbf{M_{LS}}\) in efficiency. Figure 4: The interaction effects between the operation method and in-vehicle location (mean [standard deviation] values of each design alternative for each measure): (**a**) accuracy, (**b**) efficiency, (**c**) rapidity, (**d**) learnability, (**e**) intuitiveness, (**f**) safety, (**g**) preference, (**h**) memorability, and (**i**) satisfaction. The blue, orange, and gray asterisks indicate significant in-vehicle location effects for the lever slide, button push, dial rotation methods, respectively, and the black asterisks indicate significant operation method effects for each in-vehicle location. * When the in-vehicle location was \(\mathbf{L_{LCF}}\),
* \(\mathbf{M_{LS}}\) showed significantly higher mean scores than \(\mathbf{M_{DR}}\) in safety. * \(\mathbf{M_{BP}}\) exhibited significantly higher mean scores than \(\mathbf{M_{DR}}\) in learnability. * When the in-vehicle location was \(\mathbf{L_{CC}}\),
* \(\mathbf{M_{LS}}\) showed significantly higher mean scores than (1) \(\mathbf{M_{BP}}\) in accuracy, learnability, and memorability and (2) \(\mathbf{M_{DR}}\) across all nine measures. The statistically significant simple main effects for in-vehicle location are as follows:
* When the operation method was \(\mathbf{M_{LS}}\),
* \(\mathbf{L_{UCF}}\) showed significantly higher mean scores than \(\mathbf{L_{LWS}}\) in accuracy, intuitiveness, and safety. * \(\mathbf{L_{LCF}}\) exhibited significantly higher mean scores than (1) \(\mathbf{L_{LWS}}\) and \(\mathbf{L_{RWS}}\) across all measures except efficiency and rapidity and (2) \(\mathbf{L_{UCF}}\) across all nine measures. * \(\mathbf{L_{CC}}\) had significantly higher mean scores than (1) \(\mathbf{L_{LWS}}\) and \(\mathbf{L_{UCF}}\) across all nine measures; (2) \(\mathbf{L_{RWS}}\) across all measures except efficiency and rapidity; and (3) \(\mathbf{L_{LCF}}\) in learnability and intuitiveness. * When the operation method was \(\mathbf{M_{BP}}\),
* \(\mathbf{L_{RWS}}\) showed significantly higher mean scores than \(\mathbf{L_{LWS}}\) in intuitiveness, preference, and satisfaction. * \(\mathbf{L_{UCF}}\) exhibited significantly higher mean scores than \(\mathbf{L_{LWS}}\) in accuracy, intuitiveness, and safety.