Sunday, April 10, 2011

The King of zig-zag driving

have you ever experienced some old guy smiling in his car thinking "that was a crazy bastard." of you? well, that is how he appreciates your speed, your style, your passion and your guts.. this is a typical scenario when he watches you approaching through the rear view mirror, blinks his eyes once and observes you flying away through the front windshield. a quick experience of the Doppler Effect... violate shift of your head lamp to red shift of your tail lamp!

today, i want to share a driving experience i had a few days back. i was driving my car, Carbon, to Ahmedabad from Mumbai. on that route Surat to Vadodara is a six lane road, with heavy traffic. a lot of buses and trucks use that road and unfortunately they drive on all three lanes of a side! there are two wheelers too alongside cars... but all that make the drive really challenging, enjoyable and eventually memorable. i drove around 200km at an average of around 100 kmph. and during the trip i thought of zig-zag driving... formed some rules and followed them...

some of the rules are here...
- drive in such a way that others do not have to break because of you.
- do not make anyone honk unnecessarily.
- accidents are fatal, avoid them.
- don't hurt your car.

it is a harsh world out there. if you do anything wrong, people honk. you lose points for such mistakes. so, timing is crucial on every stage, whether it is pushing the clutch paddle or shifting gars or turning the wheel or pressing the accelerator... any of the timings is wrong and your car would groan in pain. making anyone break is literally a crime. accidents can show you the way to a prison or a hospital or even the one-way to the dead-end. so, keep all your five eyes in action...

zig-zag driving is not a one man show, rather it is a double act. you and your machine, your car. you should know your car inside out. what it can do and what it can not... how fast it can go and how quickly it can stop... how much space it requires... when it needs a gear up and when a steering turn... what its mirrors show and what its door frame hides... your car is the extrapolation of your body or you are just the decision making 'part' of your car!

it is a challenge for your body... coordination among various body parts... your eyes on the road... your one hand on steering and the other on the gear changer... your one leg on the clutch, other handling break and accelerator... your ears, listening to the music your car deck plays... your brain and spinal cord gathering information, assessing and responding in real time... it is a challenge for your sensors, controller and actuators. you are a mechatronic system! it's a test of capability of your brain to control these organs and of your organs to react to the command. it is a test for your sub conscious as well...

zig-zag driving is a dynamic phenomena. all the dimensions are changing with time... distance between different vehicles are increasing or decreasing... you should judge not only if your car can pass through a passage, but also what would be the size of the passage as you would approach it. your angle of approach to the passage also has a say as your requirement of space changes in different direction... you are a heterogeneous body!

again not only distance, velocity and accelerations are important, jerk also plays an incredible role. when to hit the throttle and how hard... for how long before decelerating... again breaking is not uniform.. and it does not stop at jerk or third derivation of distance... sometime you wait for a passage to open and as it opens you rush trough it... sometime you wait for proper approach angle, break suddenly, change angle and speed up to enter a closing passage... you are a Newtonian body!

driving in zig zag fashion through crazy traffic needs an act of PID (proportional integral derivative) controller. it takes current, future and past events in account while deciding an action. you should know of the current position of all the vehicles around as you pass through them... you should know their position a little while later (integral) as that would tell you what passages would open for you... also, when and where... you should know positions and speeds of the vehicles you just passed through (derivative), so as to get an idea about which lanes to enter and which to avoid. you should know this history of past 7 to 15 seconds if you travel at around 100-120 kmph, to avoid honks... you are omniscient!

there might be more... but this is how much i could grasp... it was a lovely experience and i loved every moment of it. it was an adrenaline pumping act, but ironically i was singing a very soothing, slow, Indian classical song, Aan milo sajna... from Gadar.. however annoyed or excited you look outside, inside, you are always calm and compose!

literally no car could come close to overtake me throughout the 2 hour drive... i made no other car honk or break... and of course did not collide with anything... maintained a good speed.. and most importantly, i enjoyed my drive. i was so swift and so wonderful that i was thinking if there is a crown called 'the king of zig-zag driving'? coz if there is, i am here to claim it!