Parallel steering car

This vehicle is basically round, with maybe 5, 6 or 7 wheels. The wheels are mounted on the arms of a spider like the wheels of an office chair, and the body of the car swivels on the spider like the chair does – except that the rotation of the body is linked directly to the castoring of the wheels – so all the wheels are always pointing in the same direction as the body.

The drive runs vertically down the centre pivot of the body, then via bevel gears to shafts out along the arms of the spider, then bevel gears again and vertically down the middle of the (vertical) steering axes of the wheels, and finally bevel gears again to drive the wheels. Steering is accomplished by rotating the body on the spider (and the steering axes of the wheels in sync).

You can have a simple steering mechanism, in which case steering is a little unorthodox from the driver's point of view: you keep turning the steering wheel further and further all the way round a bend, faster for a sharp bend or if the car is moving fast, slower for a gentle bend at low speeds. Alternatively, you can have a more sophisticated, motorized steering system, where the driver's steering experience is normal, and the steering motor is driven at a speed proportional to the speed of the vehicle multiplied by the steering wheel position. (There is another option, where the steering motor speed is proportional only to the steering wheel position. This might actually be nicer to drive, and possibly safer, too.)

There is of course no magic about having to have the body always pointing in the same direction as all the wheels. The most obvious time you might want to disengage this lock would be to reverse direction, when you might turn the body through 180°, but reverse the gears rather than scrubbing the tyres round 180°, but you could if you liked simply face sideways relative to the direction of travel for a while. Great for disconcerting fellow motorway users, or for glaring at the chap tailgating you!

Also good for driving sideways into and out of a parking space, requiring no space in front or behind at all (tough on the folks each end!)

Good for loading and unloading, and getting in and out – always at the kerb side.

The main drawback is that the vehicle is as wide as it is long – meaning probably a maximum length of 2.4m for a road vehicle. (The body can be longer, of course - but the wheelbase is always a regular polygon.)

The other noticeable drawback is that you either have small wheels, which are okay on good roads but no good off road, or the whole vehicle is rather high off the ground and consequently difficult to make stable on or off road. Maybe a small wheeled version would be good on good but icy roads, and possibly a very big (more than 2.4m diameter) version for completely trackless country.