When a car is in neutral, it is temporarily disengaged from the gearbox. This allows you to push a stalled car and it allows you to take your foot off the clutch in a manual transmission vehicle while you are at a stop.
When a vehicle turns at a rate exactly proportional to the rate at which the steering wheel is turned, it is said to have neutral steering.
Nitrogen Oxide is a toxic by-product of internal combustion. When dissolved in moisture in the environment nitrogen oxide causes acid rain and pollution. The catalytic converter in your car helps reduce the amount of NOx present in your exhaust.