Various systems and techniques for providing enhancements to bogie-equipped vehicles are described and discussed. Such systems and techniques include, for example, actively driven bogie differentials, elevated obstacle mounting techniques, worm-drive steering, parking modes using toe-in or toe-out wheel steering, speed-sensitive steering mode selection, and various other enhancements and techniques.

A vehicle shutter device includes first and second flaps, one actuator, and a link mechanism. The link mechanism includes a connecting rod that couples the flaps to each other such that the flaps rotate in synchronization with each other. The shutter device is provided with stoppers configured to prohibit each of the flaps from being displaced beyond a normal opening and closing range when the link mechanism is in a normal state. When coupling between the connecting rod and the first flap is released in the first pivotally attaching portion in a state where coupling between the connecting rod and the second flap is maintained in the second pivotally attaching portion, the actuator is allowed to rotate beyond a normal rotation range of the actuator corresponding to the normal opening and closing ranges of the first and second flaps.

Various systems and techniques for providing enhancements to bogie-equipped vehicles are described and discussed. Such systems and techniques include, for example, actively driven bogie differentials, elevated obstacle mounting techniques, worm-drive steering, parking modes using toe-in or toe-out wheel steering, speed-sensitive steering mode selection, and various other enhancements and techniques.