Tesla has been talked about the world over lately with its rumour Model D expected to get unveiled last night. But rather than a new car being unveiled the D, it turns out, was a variant for the Model S.

Tesla CEO Elon Musk was teasing the Model D, and something else, which has now been revealed as upgraded sensors that take Tesla a step closer to the self-driving car Musk has promised is coming next year.

The Model D wasn’t a new model in itself. But that’s not a bad thing. The D is part of the name All Wheel Drive which is being added to the Model S first and then to other models at a later date. The new AWD option will add a second motor to the car which drives the front wheels. Current models are rear wheel drive only.

The Model S P85D will offer all the options of the top end Model S but with all wheel drive. Surely this means lower range? That’s what we’d expect but as ever Tesla has impressed by actually extending the range in spite of driving all four wheels.

The AWD Model S manages a range of 275 miles on a charge. No less than the current top end two-wheel drive model then. Before you fret about power, that’s improved too, somehow.

The Tesla Model S P85D can manage a 0-62mph start in a tyre screaming 3.2 seconds. This is very much an all wheel drive supercar. Tesla uses two chargers meaning once that battery is all used up it can be charged at double the speed using the 80 amp Wall Connector meaning 58 miles of range per hour of charge.

Elon Musk promised something extra at his announcement. It wasn’t directly related to the AWD model. Rather it’s a set of improved sensors that makes the Model S more intelligent.

A lane departure warning has been added which, as you’d imagine, will alert a driver when they veer out of their lane. The Model S will use 12 sensors meaning it should be able to “see” 16 feet in front of the car so it’ll be able to guide the car over a lane when the driver uses the turn signal. It will also be able to read speed-limit signs and adjust the vehicle’s speed to keep it legal. Hopefully there’s an off button for this, you know, in case of emergencies.

The new sensor only works in the latest models, meaning older model owners can’t upgrade. Ultimately this is working towards a Tesla that is smart enough to drive itself automatically. Elon Musk has said publicly that by next year Tesla will offer a self-driving car that manges 90 per cent of driving automatically.

The new Tesla Model S P85D can be ordered now. They will start being built in December. The Tesla website says that the AWD options will begin shipping in February. It lists the model at $120,170 which is about £75,000. The standard Model S can have AWD for an extra $4,000 totalling $90,000 which is about £56,000.

READ: First Drive: Tesla Model S - Pocket-lint