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Adaptive cruise control in the test: mid-range cars

Beate Jeske, Reinhard Schmid
Adaptive cruise control for A5, 5 Series, Mondeo and Passat CC
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E s sounds still like a story from the distant future, when cars automatically brake, accelerate and maintain the correct distance from the vehicle in front. But such adaptive cruise control has been a reality on German roads for nine years. In 2006 auto motor und sport, together with TÜV Süd, was the first and only magazine in the world to carry out a comprehensive test of these systems, known for short as ACC (Adaptive Cruise Control).

Have the adaptive cruise control really improved?

At that time, the radar-based systems were still very expensive and reserved for the upper class, but now mid-range drivers are also allowed from around 1,100 euros extra Get to your destination with less stress. Let's look back to 2006: Although the systems did well in the traffic in line, auto motor und sport criticized the distance and acceleration behavior. The cars picked up speed as tough as chewing gum and in some cases did not manage to keep the driver away from the Flensburg points with the correct distance. Can the 2009 generation do that?

Nothing has changed in terms of functionality

In the end, nothing has changed in terms of the basic functionality: A radar installed in the front section measures the distance with a club-shaped 77 GHz measuring beam (long-range radar) to the front man. Particularly complex systems like the one in the BMW 5er also work with a 24 GHz radar, which increases the detection range at close range. Its three competitors, on the other hand, rely solely on the values ​​of the long-range radar. On this basis, the accelerator and brake controlled by the electronics regulate the distance to match the speed. Depending on the car, the driver can choose from four to five distance levels. There is always a minimum time gap of around one second, which when converted into meters corresponds to a little more than a quarter of the speedometer value. Whoever complies with this will at least not get a fine.

ACC systems solve problems differently

In contrast to the first test, modern mid-range cars have no problems maintaining this minimum distance with moderate speed differences from the vehicle in front. Only the Ford Mondeo Slightly below the quarter speedometer limit when accelerating from 130 km /h to 90 km /h. Much more serious, however, is that when the speed increases by 80 km /h to the vehicle in front, the Ford driver has to apply the brakes to prevent an accident. His ACC system recognizes the situation over 13 meters later and reacts too slowly. The other three systems solve the situation without any problems, albeit in different ways: The VW likes strong, rough braking, the BMW likes early, if on average not particularly strong, decelerations and the Audi on responsive, harmonious braking.

Only the BMW 5 Series can drive off automatically

When the cars move back into the left lane, they then accelerate automatically, resulting in similar characters. The Audi accelerates early, but a bit hesitantly, while the BMW automatically accelerates courageously. Both the VW Passat and the Ford Mondeo need on the other hand, it takes a long time to get going. An additional handicap with the Ford test car is the manual transmission - an unsuitable partner for an ACC system. BMW 5 Series and Audi A5 get theirs Reaction advantage thanks to a small but clever trick: As soon as the driver activates the left turn signal, the electronics release fire for the gas. If the car in front comes to a standstill, the BMW plays takes advantage of its two radar systems and brakes to a standstill. The Munich business jet is the only one in the test that can also automatically drive off in stop-and-go traffic.

All systems warn of an impending collision

In the VW Passat CC the occupants get more than 0.4 g in extreme cases Feeling strong braking to a standstill - good for safety. The simple brake system pumps clearly audible - bad for comfort. However, the VW driver has to drive off again himself. Both the Audi A5 and the Ford Mondeo exit the automatic deceleration party at very low speeds with a warning tone. This, too, has improved compared to 2006: All systems give a very clear warning of an impending collision or approaching too closely. Since no driver in the world is constantly fully concentrated, this help is one of the greatest advantages of ACC systems. Even when the distance is switched off, they serve the safety of the car occupants. In theOperation can meanwhile all squint over to the class-leader Mercedes, which shows with its ingenious steering wheel lever solution, how easy it is.

The most expensive and complex ACC system wins

Especially newbies will bite their fingertips at the numerous steering wheel buttons and the logic of the Ford Mondeo. The control units of the three other test cars, which are designed as levers, are all hidden behind the steering wheel, and setting the distance levels is very fiddly with small rocker switches. The most expensive and complex system in the BMW 5 Series just won the race. The Audi pleases with its comfortable control and the beautiful distance graphics, the VW convinces with sheer braking power, and there is still a lot to do with the Ford Mondeo.

Audi A5 Sportback
The Audi is the electronic finesse in the test: It regulates the most harmoniously and is the only one that allows its driver to choose between different dynamic levels of its ACC system. s² is not at the top, but it reacts the fastest. It very rarely shows false detections on the autobahn.

auto motor und sport verdict:
highly recommended

BMW 5 Series
The BMW 5 Series covers the widest range of speeds and, with its two radar systems (far and near), can also handle stop-and-go traffic.

It is easy to control and it accelerates tremendously when pulling out. What tarnishes its good performance, however, is the not always reliable detection of motorcycles or cornering.

auto motor und sport verdict:
highly recommended

VW Passat CC
Strongly and consistently, the cheapest ACC system even brakes to a standstill in the test.

This is for driving safety. Its inharmonious regulation is at the expense of driving comfort. The step-like regulation and the pumping noise of the brake are also disturbing. When pulling out, the VW Passat waits too long before it accelerates again.

auto motor und sport verdict:

Ford Mondeo
With its late, weak and inharmonious reactions, the Mondeo is the loser of the ACC test.

When driving into excessive speed, even the driver has to intervene. In addition, its system recognizes objects much later than those of its competitors. Its weak acceleration is partly due to the fact that it started the test with a manual transmission.

auto motor und sport verdict:
not recommended


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