Better Riding: The invisibility conundrum

Arti and I were driving in a Volkswagen Passat to Vadodara and we weren't hanging around. To our horror, I discovered that we repeatedly got squeezed by trucks who would pull into our lane at the last possible minute. At first, I thought it was a vicious conspiracy of some sort. This thought returned to me when I heard of an accident recently outside Mumbai where a trailer pulled into the fast lane at the wrongest possible time, crushing a young Mumbai motorcyclist to death. The news reports said he was a good rider and seemed to blame the truck driver. But as I learnt from the Passat experience, fast moving vehicles become invisible, it is pure physics and biology and not really a matter of skill. Allow me to explain.

Imagine the average Indian truck driver. He's driving a clattery, noisy, slow thing that goes like a bicycle and turns like a supertanker, right? How often do you think he checks his mirrors? Let's say the truck is going 60kmph - this is a good bet. Most truck drivers will check their mirrors before they start making a lane change. You can argue that they don't, but as an attentive watcher of other drivers in their mirrors, I know that almost every truck driver does actually check his mirrors, small as they usually are before he makes a change of direction. But at 60kmph, if he glances at the mirror every 3 minutes, he's looking at the road situation every 3km. That is actually not a bad frequency, right? Let's say he's lazy and takes 5 minutes to return to his mirrors, that's 5km covered between mirrors checks. Think about it, if he checks the mirrors every minute, he's almost not looking where he's going!

So how did the trucker not see the biker? or my Passat? Both had their headlights on!

The problem is our speed. At 100kmph, we are covering 91 feet every second. That means you were 5km behind our alert trucker when he last checked his mirror. And the next time he checks his mirrors, you're right behind him (he's also moving, remember?). But since the difference is 40kmph, there's a good chance he spots you.

If you want to be precise and add the fact that the truck travelled 3km between mirror checks and account for it, the calculation changes but only a bit. So if he's going 60kmph and you're approaching at 100kmph, there will be some combinations where you will not be in the mirrors when he looks. You'll appear in his windshield as a rapidly disappearing vehicle he's shaking his head at after the overtake.

But do most of us stick to 100kmph? We all mostly do 130kmph when the traffic is light and visibility is good, right? 130kmph is just under 7km every three minutes or 11.4km every five. In many cases, these are distances beyond comprehension or visibility. You were at home when he checked his mirrors and the next time he checked them, you'd reached your workplace. And trucks slow dramatically on upslopes too - we don't.

In essence, you were invisible to the truck driver for all practical purposes. So what do you do? First, we have to become aware of our closing speeds as a barrier to our visibility. It means flashing your lights at a truck for an overtake when you're approaching at speed needs to start much earlier than you think. If you're not confident that got his attention, you might have to honk as well. In a more orderly country, lane discipline is preventing half this problem, the other half is taken care of by strong licensing, enforcement and generally more patient drivers. Tip: slow down!

Second, you cannot become complacent once you have a high-visibility vest on. If you're riding at a good clip, you have to actively make yourself visible using your headlights, colours, lane position and yes if you must, your horn. But most importantly, pay attention to how fast you're approaching a vehicle ahead. Depending on your speed, they may have no chance of seeing you at all!