Reasons not to trust anything electrical when there has been nothing really wrong with the feel of a nice cable operated emergency brake, apart from that it may induce even less concious thinking by the driver.
Firstly, anyone who has experience of early British cares will know all about the Prince of Darkness, Paul Lucas and his car electrical systems. So there is a natural suspicion of overly sophisticated electrical systems where in the past even getting the headlights to shine was a problem.
Secondly, anything with computers naturally involves computer programmers. Then we have the experience of the "blue screen of death and its non-MS equivalents.
Either on leads me to dread the day that my car would find the failure mode that will leave me in a ditch or wrapped around a tree or crunched under an artic.
Let's consider an example.
The Citroen C5 has 9 computers on board. This was a major feature of their advertising.
I had one.
Not the earliest but not long into the life of this model.
I would be driving along at night when I'd note a flicker of the headlights as if they'd momentarily gone off and on again.
They had.
In earlier models it was even more alarming as they might go off for an appreciable period of time - when hacking along an unlit road at night and at 100-110mph, appreciable can be quite short but very scary.
Note that they didn't fix the problem properly in one go because my version still had the momentary flicker (which can be both worrying and distracting until you know what is going on).
Every time you went for a service they'd update the software.... so eventually and after who knows how many iterations, they did fix it.
The C5, like many of the Citroen cars has hydraulic suspension.
The engine drives a compressor which charges the reservoir which supplies the braking and suspension systems.
When the pressure starts to get low the compressor kicks in.
It apparently draws something like 60amps.
Now, the alternator is not always on.
When the battery is fully charged it is de-clutched to ease the load on the engine.
So if you are driving along at night with the alternator de-clutched and the compressor suddenly cuts in, it hogs all the battery output and the lights go out. Then the alternator cuts in, the lights come back up and you start breathing again.
It seemed to take forever to finally get the system to work in such a way that when the pressure dropped, the alternator come on first then the compressor could run. One guesses that at first they tried simply to synchronise the two which is why I got the flicker, but in the end it was a do this first then do that solution.
Oh yes, suspension. AT speed the computers adjust the suspension for "better" handling. This also includes lowering the front end of the car a trifle. Or that was the intent. They discovered with mine that at speed it raised the front end of the car.
So now we have a sophisticated electric/electronically controlled emergency brake system and I should trust it?
What was wrong with cable systems and lever or a foot pedal? (I prefer the handbrake version myself either conventional or fly-off).
While one might suspect self-adjusting mechanisms especially if old and full of dirt, they can be effective and you know from the amount of pull up on the handbrake lever when the cable has stretched or the system needs adjusting. Apart from the cable snapping, which you will know about when it happens, this is a relatively simple and understandable system (more complex with disc brakes all round), and still relatively fool proof.
If you are going to mess around with it, don't call it an emergency brake system any more.
JMW
