The Mercedes-Benz predicted its new E-Class sedans would introduce a new dimension of safety, comfort and stress relief when it introduced the models last year.

Driven is testing that claim with a three-month trial in the base-model E200, seeing just what the much-acclaimed Car of the Year delivers to everyday motoring.

So far we have established the E200 is a relaxed, luxury large sedan that delivers on the comfort and stress-relief claims.

With almost 2000km behind the wheel during the last month, there is no doubt the $99,900 E200 upholds the German marque's reputation for delivering elevated levels of comfort and style.

The system works even if road markings are indistinct, or there are no lines on the road at all. However, there are warnings for the driver to keep hands on the wheel, reminders that only semi-autonomous driving is allowed at present.

The interior is spacious and stylish with the brand's signature sweeping chrome finishing touches, and the huge twin-screen that stretches a full two-thirds of the way across the dashboard.

The car rolls along nicely on the 18-inch standard wheels, and the smooth ride is helped by the nine-gear automatic gearbox matched to the 2-litre 4-cylinder direct-injection turbocharged engine.

Buyers seeking more oomph and sports sedan performance need to look at other models in the E-Class range, although this is no slouch with a 0-100km/h time of 7.7 seconds.

Where the model stands out, however, is how it moves closer to the ultimate aim of autonomous driving, with new driver assist and safety features.

Whereas adaptive cruise control systems are appearing in many cheaper vehicles now, the Intelligent Drive system on the E-Class models is automatically able not only to keep the car at a correct distance behind slower vehicles, but it can also follow them in their lane, at any speed up to the legal maximum.

This means the car will virtually drive itself, with the driver not having to use the brake or accelerator pedal during normal driving.

The driver must maintain vigilance and there is a warning on the screen in front of the driver if the car believes hands have been off the steering wheel for too long.

If for some reason, say a heart attack or other illness, the driver is unable to respond to these warnings, the car will gradually slow down and bring itself to a stop.

But, hopefully, we won't be testing this safety feature (or the many others on the E200) during our long-term loan.

Gaining confidence in the systems takes a while, because it is quite a leap of faith to give up any control while behind the steering wheel.

However, once you build confidence in the systems onboard, they make for a more relaxed driving experience, especially on overcrowded roads such as State Highway 1 in any part of Auckland.

The comprehensive nature of the systems onboard the E200 are confidence building, because they do exactly what the driver instructs.

The driver remains in charge and responsible for what is happening, but the systems will follow the road, even taking a bend.

They do this by using a huge range of sophisticated radars, sensors and multi-purpose camera systems that identify potential hazards around the car.

The adjustable safety distance can be set when following other cars, and it is quickly mastered by using a small stalk on the left-hand side of the steering column.

A button on the end of the stalk controls other parts of the Drive Pilot system, including self-parking functions and automatic lane changing.

A small green steering wheel symbol shines on the dashboard to indicate the system is activated; the left-hand indicator signals the intention to change lane; and the car checks its surroundings to determine whether it is safe to make the manoeuvre, then imply steers into the chosen lane.

The Mercedes will not make the move if it detects an obstacle in the chosen lane, or if the driver overrides it by taking control of the steering.

But it is not only the driver and passengers who benefit from the semi-autonomous features on the E200.

It is fitted with an active braking assist program, with pedestrian detection evasive steering assist. This system provides a boost to the braking if it detects, for example, a pedestrian ahead, and the driver has applied too little brake pressure. It also has evasive steering assist, which will autonomously turn the wheel to ensure the car avoids a pedestrian ahead, then straightens the car up so it stays on the road.

Although many other premium models have similar systems, some operate only at relatively low speeds. However the Mercedes-Benz collision avoidance operates up to about 60km/h.

It also has a function to reduce accident or injury severity up to around 70km/h, depending on the circumstances.

If the safety systems decide there is no way of avoiding an obstacle, it initiates emergency braking functions, which include boosting the braking power over and above what the driver applies.

There are also side-collision detection features, where air chambers inflate and the driver is propelled towards the centre of the car and away from the crash impact on the side of the car, reducing the risk of injury.

In addition there is pre-safe sound, which reduces the effects of noise stress caused by collisions.

It produces a short white noise signal through the car's sound system, which prepares the driver's inner ear for the imminent crash. It effectively disconnects the ear drum and inner ear, reducing the risk of hearing damage from the collision.

This is definitely one feature of the E200 we hope not to test as we continue our three-month test.