BMW.automotiveITBMW did best in our premium-segment HMI test, so I was keen to try out a BMW 535i on a recent 1,800km roundtrip between Munich and Amsterdam. I set out to get a subjective impression of the ease of use of BMW's connected infotainment and driver assistance systems. No attempt was made to do a comprehensive test of everything. Here's what I found.

I didn't check out the growing range of online infotainment options available in the BMW, but played with the RaRa streaming music service. Once it was up and running, songs sounded good and it was easy to select genres and move to the next track. It was difficult, though, to find out how to switch from one genre to the next.

As I have found in other test cars, the systems that worked best were the ones that have been around longest. Connecting my LG android smartphone via bluetooth was as easy as screwing in a lightbulb. My lengthy phone directory was transferred quickly and making and receiving calls was simple and intuitive. The same was true for connecting my trusty old iPod via USB. With phone reception spotty in many places, having your music in the car still beats any streaming option, in my experience.

I had a serious problem with the BMW's messaging software, which may be something smartphone or Android-specific. The car can read my text messages. So far so good. But it only reads them in the preset language of the operating system. I get messages in English, German and Dutch. Because my system language was English, the latter two were read out to me in such a way that I, literally, couldn't understand a word. Am I the only driver who gets messages in more than one language?

The navigation system, with its real-time traffic alerts, had good and bad features. On the positive side, the redesigned iDrive knob lets you use finger gestures to select characters, which makes entering addresses much easier. It's also less distracting than other input modes and it worked better than voice. The maps were good and direction arrows were always clear. The traffic assistant suggested too many detours for what often were relatively minor bottlenecks on the highway. And at one point, the system told me the German autobahn was closed, while it was actually open but reduced to just one lane.

I used the BMW's adaptive cruise control extensively on the autobahn and on smaller country and urban roads. In normal traffic, the system worked well, but it sometimes reacted too defensively to perceived obstacles by the roadside that proved to be no problem at all. Though that was irritating, it's probably not a bad thing. Better safe than sorry. A bigger problem was that the car's sensors often didn't respond particularly well to bends in the road. With the ACC set at 80 kmh, the BMW would be automatically keeping a safe distance from the car in front, which might be going at 60 kmh. But once that car would go around a curve or maneuver through a roundabout, my BMW would often no longer "see" it. The result: I would automatically accelerate to 80 kmh at a potentially dangerous place and time

BMW's concierge service, which answers any question you want, worked quickly and well. Given its popularity - both with BMW owners and in other brands that offer a similar service - it is clear that, as the sophistication of in-car systems grows, there will be even more need for a good helpline staffed by humans.

Two technologies that have also been tried and tested for a while need mentioning: blind spot detection and the head up display. Both were probably the single biggest help to me on my 1,800km journey. More than any other feature of the car, they provided true driver assistance and helped combat distraction. The same can be said of the speed limit sign recognition, which worked almost flawlessly.

Was I distracted by the controls I could operate during my trip? The answer is yes, but not because of anything BMW did badly. It's clear that tuning a radio, searching for a music track, putting in a navigation address or talking to the helpline requires a lot of mental energy. That energy then is no longer available for driving. That's not a problem that can be easily solved. It may never be solved completely. But it's also not something that's all that different from talking to physical car passengers while driving. Or dealing with children in the back seat or eating lunch with a sandwich in one hand and a cappuccino in the cup holder.

Our full HMI test, which looks at the Audi A3, the BMW 1 Series and the Mercedes-Benz A-Class, can be found in the October edition of the automotiveIT international Executive Report, which is available for subscription at http://www.automotiveit.com/executive-report.

-By Arjen Bongard