At 6am, it's hard to believe we're in the same city we were the previous evening. Patna is a completely different animal when it's not rush hour; there's even a sense of calm discipline to the traffic. Still, the drivers are vying to drive the more compact, more manoeuvrable Audi A4, rather than the long and wide A6, just in case. I quietly snatch the keys and hop into the driver's seat while no one is looking.

In the daytime, and without the distraction of a million honking horns, we actually get to take in a bit of the city. And it's quite a pretty thing to behold. There's a stop at Golghar (a huge dome-shaped granary built by the British in 1786) for a quick shoot. This time, we fall prey to the sat-nav's 'shortest is quickest' route guidance philosophy, and spend about forty minutes navigating a narrow market road.

Soon, we're out of the frying pan of Patna city and into the fire of rural Bihar. The roads aren't as bad as they were on the way in, and we dispatch the first 150km in time for a late breakfast in a tiny town. About a dozen aaloo parathas later, we notice some CDs at the store outside which, judging by their covers, appear to be some form of adult entertainment. The shop owner quickly and enthusiastically points out that it is actually the very latest in Bhojpuri pop music. How could we not sample some! And you know, it's pretty good actually - both cars are singing along before you know it.

It's enough to lighten the mood when we shift from NH30 to NH31 and things start to get really sour, road surface-wise. These are no longer potholes, not even craters. These are elevation changes; it's a geologist's dream. Suffice to say we're rock-crawling now, not driving, and I wonder if we would have been better off in Audi's Q cars instead. All unfounded, the two saloons are carrying on amiably, putting their wheels just where we want them - crucial if you want to get through a stretch like this with your undercarriage in one piece.

By the time we're done with this godforsaken stretch of unfinished road (I use the term loosely), it's gotten quite late, and we really need to get a move on if we want to make it to Siliguri at a decent hour. As if as compensation for the drive we've just had to do, we're treated to the nicest stretch of dual carriageway we've seen since the start. We pop both cars into Sport mode and live a little.

The road even widens to a four-laner towards the end, and as the sun goes down, we cruise across the border into West Bengal. And would you believe it, just minutes into the state and it starts to drizzle. At this rate, we'll have thunderstorms by the time we hit Mawsynram. Visibility isn't great and progress has slowed down a bit, but there isn't too much traffic. We even stop for some tea and snacks and to take in the moist post-shower evening air.

Siliguri is almost unrecognisable from the last time we came here. There's a massive new mall, and loads of new buildings. But it still has the same peaceful charm it always did. It's a slightly confusing twist off the highway into our hotel, and once we've checked in, the weather is so good, for the first time on this trip, we're happy to just hang around outside for a little while.