## 4 Capability on Obstacle Avoidance
### Comparison with Passenger Cars and Motorcycles
#### 4.2.3 Passing Speed Comparison and Understanding Social Acceptability  
In the case of CarMaker, longitudinal speed is controlled consistently and automatically, but lateral control is switched from straight running model to automatic steering control model just before the transition section. The straight running model runs in the middle of the lane, but the automatic driving model takes the most advantageous course (feint motion) as far as possible, even if a narrow course width is set. For this reason, after entering a single lane change course, the model is switched from straight running model to automatic driving model. Switching timing was set as early so as not to miss the inner pylon and as late so as not to take the most advantageous course. Driver parameter and maneuver are shown in Table 4.  
\begin{table}
\begin{tabular}{|l|l|l||l|l|l|} \hline \multicolumn{3}{|c||}{**Passenger Car**} & \multicolumn{3}{c|}{**Motorcycle**} \\ \hline
**Item** & **Unit** & **Value** & **Item** & **Unit** & **Value** \\ \hline Total length & m & 4.150 & Total length & m & 2.140 \\ \hline Total width & m & 1.700 & Total width & m & 0.637 \\ \hline Total height & m & 1.600 & Total height & m & 1.318 \\ \hline Wheel base & m & 3.185 & Wheel base & m & 1.576 \\ \hline Front tread & m & 1.508 & Front mass distribution & kg & 122.8 \\ \hline Rear tread & m & 1.494 & Rear mass distribution & kg & 75.5 \\ \hline Total mass & kg & 1463 & Total mass & kg & 198.3 \\ \hline Gravity center height & m & 0.580 & Gravity center height & m & 0.350 \\ \hline \end{tabular}
\end{table}
Table 3: Specifications of passenger car and motorcycle.  
Figure 22: Three levels of severity on driving course were set by parameter study.  
In PMVs and passenger cars, vehicle speed is automatically reduced when entering speed is quicker than passable speed. Therefore, in general, entrance speed (avoidance speed) to the transition section and exit speed from the transition section are different. In this study, entrance speed to the transition section was used as passing speed. In the case of PMV, only one occurrence of front inner wheel lifting was accepted and repeated liftings were judged to be failed.  
In the case of BikeSim, autonomous maximum speed driving in the given course is not possible. A target trajectory was given to the rider model to drive a similar course to the PMV. The preview time was set according to the model switching distance in the PMV and the riding manner was adjusted by the behavior gain of tilting. The speed was gradually increased and it was judged from actual trajectory whether it was successful or not. The target trajectory was adjusted to get maximum passing speed in necessity.  
A comparison of the maximum avoidable speeds is shown in Figure 23. As is generally understood, it was confirmed that there is a large difference between passenger cars and motorcycles. The capability of obstacle avoidance for PMVs is not only clearly superior to motorcycles, but is also equal to or higher than passenger cars. Therefore, we may understand that PMVs have sufficient social acceptability in terms of capability of obstacle avoidance.