Possibly challenging Noeleen on stupidity here 
So the Merc Antos has a little cubby hole (two actually) near the handbrake, I usually put things in the cubby hole nearest the handbrake like the works phone with my headphones in, I remember on one occasion the headphones wire got wrapped around the handbrake and I pulled the headphones off when co-driver woke up and nearly pulled the handbrake upā¦
What would happen? In a modern vehicle like this would it know Iām driving and not to fully apply the brakes or would I kill us all and any cyclists nearby?
Pull the air brake while your driving and you will soon find out. Iād like to think by now they could fit a gizmo to stop it being applied by accident by now.
Important disclaimer:
But no seriously do not try the above advice you will die doing it at speed for sure.
Way back driving buses, we had some Leyland Nationals. Very nice bus to drive, but the stubby gear lever for the five speed box was right above the handbrake. The handbrake was sprung to on, so you can imagine what happened when your wrist touched it as you were changing up. 
Ghiabox:
Possibly challenging Noeleen on stupidity here
So the Merc Antos has a little cubby hole (two actually) near the handbrake, I usually put things in the cubby hole nearest the handbrake like the works phone with my headphones in, I remember on one occasion the headphones wire got wrapped around the handbrake and I pulled the headphones off when co-driver woke up and nearly pulled the handbrake upā¦
What would happen? In a modern vehicle like this would it know Iām driving and not to fully apply the brakes or would I kill us all and any cyclists nearby?
On a modern truck, the first bit on the handbrake is your āsecondaryā brake, this is up to the lock where you have to lift the handle a put up to lock the parking brake.
The secondary brake works progressively, e g the further you pull the handbrake the harder it brakes.
Itās the emergency bit of your brakes.
As there is no ABS / EBS working at that point on full brakes it can skid in the wrong condition.
On a tractor unit in general it applies the trailer brakes first, to keep the combination in line.
As long as you donāt put it n handbrake mode (passed the lock) you can brake controlled to a certain extend with your handbrake.
However would you drop it into parking parking mode it releases the other brakes and only locks the wheels fitted with the spring brakes. (Except DAF with only parking on the drive, there it will activate the trailer brakes also)
So it possibly wont kill me unless I pull it all the way, I donāt ever intend on using it when driving as the exhaust brake is lethal enough but its good to know a slight pull wont result in locking the wheels.
Thought it locked the trailer brakes up on an artic too not just unit brakes?
Ghiabox:
Thought it locked the trailer brakes up on an artic too not just unit brakes?
If the handbrake is on then theres pressure on the yellow line and the trailer brakes should be on. If its off then no pressure. Just like when you press the foot peddle as the unit cant always hold 44T by itself, eg: on a hill.
There might be some units where the trailer only gets engaged at a certain point from the handbrake but not come across one myself. Presumably it is graduated in pressure.
Never pulled one fully on at any speed in an artic but did in a rigid - not massively quick, maybe 20mph, but boy did that slow fast! I was going for the gearstick (but it was an auto).
In an artic i could imagine carnage even with ABS. Whispers, have nearly done it when not thinkingā¦
