Are a cars tires parallel?

Are a cars tires parallel?
Depends on the condition of the car, the design of the car andthe driving conditions.

Ideally they should be, but there's a bunch of things chat canchange this.
In a front wheel drive car in good condition, the front wheels arealigned to be parallel under power. Sincesuspension parts flex a bit, this means that the front wheels willbe a little bit toe-out when the car is coasting, and a bit moretoe-out during braking.
If it's a rear drive car, front wheels will be parallel whilecoasting, but toe-out during braking.
Rear wheel alignment will also vary with design. Cars with solidrear axles will have rear wheels parallel with each other, andmostly parallel, but not necessarily in line with the front wheels.
Cars with split rear axles will usually follow the same toe-in/outvariation as front wheels depending on if the car is coasting,braking or under power.

Then there's the question of suspension travel. Sometimestoe-in/out varies a little as the shocks and springs in thesuspension allows the wheels to travel up and down. It's hard toget the linkages just right and to have the car track perfectlyeven when hitting a bad bump.