But even the most alert drivers are taken by surprise on weekends when, with a vroom and a whoosh, a cavalcade of heavy bikes looms in the rearview mirror, swoops past the car and is reduced to minuscule specks on the horizon before you can react and ask, "What was that?"

And well you might ask, for these are not some newbie bikers out for a lark, but dedicated, mostly middle-aged motorcycle enthusiasts who, thanks to their fat wallets and a liberalised import policy, are able to relive their adolescent fantasies.

Their 2000 cc-plus bikes are likely imported, and though their hair might be thinning and their paunch protruding, they still dream of riding their hot rods if not into the sunset, at least hard enough to allow them the thrills they'd always courted.

Well into their middle ages now, they're successful, running companies, sitting in board meetings, negotiating takeovers, working punishing hours, as passionate about their sushi lunches as they are about the next merger.

But catch them in a vulnerable moment, and you'll probably find them poring over a Harley Davidson catalogue, checking out BMW bikes over the net, or working out the licencing requirements and import duties for a Ducati.

With a select group of friends with whom they have nothing else in common, they'll discuss speeds and RPMs and balance as they figure where they want to head the next weekend, creeping out at dawn in their riding gear, their families and personal commitments abandoned for those few precious hours when nothing matters but the wind as they streak past cars crawling along the highway at a snail's pace of 100 kmph.

Oh, they'll deny the thrill of speed, insist they're just any other responsible rider, momentarily convince you they're out merely to air their bikes, but make no mistake - they're passionate bikers for whom all that hard work is worth it as long as they can end the week with a few hard hours of speed biking.

Take 37-year old Riyaz Amlani, Mumbai-based hotelier, who rides a Suzuki Boulevard 1800 R. Or Parvez Damania, ex-CEO of Damania Airways, who owns two Harley Davidson motorbikes. Damania isn't a late bloomer, he was always interested in bikes and even had "a Yezdi pretty early in my life".

But he has since moved on and away from the rugged Yezdi, on to his two Harley Davidsons that he takes for rides "whenever I can find the time". Mostly, that is over every weekend and sometimes late at night when he rides his NightRod and VRod on the empty streets of Nariman Point.

Paul de Voijs, managing director, Volvo India, is another biking enthusiast but he came into it somewhat late in life. While he rode a Harley back in Sweden, and is keen to get a Royal Enfield in India and head off to the Himalayas for a trip, "I am not a vroom-vroom biker who likes to touch crazy speeds of 250 km per hour," he insists, "but someone who just likes to cruise."

Voijs, a "late bloomer" by his own admission, now wants to explore his wild side in his forties. His Eureka! moment came when he visited a Harley showroom to check one out, promptly falling head over heels in love with both the bike  - and the idea of biking.

Entrepreneur Navin Ansal is another biker who rediscovered his passion for the sport after a gap of 20-25 years. A teenage biker - he would ride his brother's bike - the 49-year old Ansal now has a 2000 cc Kawasaki Vulcan and a 500 cc Royal Enfield.

While he rarely takes out his Vulcan, the Enfield is something he rides regularly over weekends around his farm and towards the Gurgaon-Faridababd highway. "Riding a bike gives you a different sort of freedom, and there is a certain adventurous bit attached to it as well," he says.

Rajeev Chandrasekhar , ex-CEO of BPL  Mobile who has a slew of projects on his hands now, owns a Harley Davidson which, reportedly, has a music system fixed in it. Sameer Thapar of JCT Mills too has a Harley and rides it regularly.

Bollywood actor Sanjay Dutt rides one and even Abhishek Bachchan is reported to have a superbike in his driveway. And newly-appointed Congress general secretary Rahul Gandhi too reportedly has a passion for biking, often heading out of Delhi for off-road biking trips with his close friends.

What is it about biking that people in their middle ages get all excited and passionate about? It's not the snob value, which is better reserved for a Rolls Royce or a Lamborghini. It's not just about the speeds and thrills either.

"It is the simple pleasure of riding the machine to de-stress yourself," says Damania. Or is it that these aren't your average, everyday commuting bikes - that they're superbikes or, perhaps, vintage bikes?

Blame some of it on the movies in recent times, even though they show the bikers in less than a positive light. But then, biking is considered dangerous, something you might associate with the "bad boy" image. "It can be dangerous," says Amlani, "if you want it to be. But if you are riding for your own pleasure and not to show off, then it can be a very pleasurable activity in the bargain."

But our middle-aged, big boy bikers will deny the thrills-and-spills school of biking - why, even the younger lot of John Abraham and M S Dhoni will tell you they're careful and slow riders. Damania says, "It's a pleasure, at the end of the day, to ride a Harley, so why go at very high speeds instead of simply enjoying it."

While speeding might earn you a momentary high, it is common sense and hardly advisable (especially given the condition of our roads and even poorer traffic sense) that it doesn't add to pleasure in the long run. "I rode my Boulevard at 220 kmph and haven't been more shaken or scared ever since," admits Amlani.

No wonder it's something he won't do again in a hurry. Amlani says even at his club, bikers practice what is otherwise known as "defensive biking". "We carry all the safety gear and take no chances at all," he insists.

Damania says he gets his kicks from taking his two children, aged seven and 10 respectively, for a cruise on the VRod. His VRod has a Porsche engine, the result, he says, of Harley's customisation options -  no wonder he fell in love with the bike twice over.

It's a fact the Harley is a cult bike, and no biker -  whether he rides a 100 cc Hero Honda or a 1000 cc Honda superbike - is exempt from its fascination. Voijs says he fell in love with one after he'd ridden a friend's Harley.

Mumbai-based architect Jimmy Mistry is one such biking enthusiast. Thirty-seven-year-old Mistry is actually a national level motocross biker but also runs architecture firm Della Tecnica. He used to ride a Harley and now has a 2300 cc Triumph.

He says ever since he was a kid he would modify bicycles by accessorising them, and later in college the bicycles were replaced by motorcycles. "To own a Harley is any biker's dream - one just has to ride it to experience the whole thing."

"The pleasure of revving up a Harley engine is something I can't put in words," chortles Damania. Listening to Damania talk bikes, one could forget that he is 46 years old, hardly considered the right age for biking! "Why should there be any age for anything, let alone biking?" Damania asks. He was attracted to the Harley for its curves, the fuel tank, the chroming, look and appeal - and, of course, the sound.

No other motorcycle has the same heart pounding in it as the V twin engine of a Harley. No wonder the company famously tried to patent its sound. "It's the sound that makes people's heads turn," says Damania. Do the envious stares and glances make him uncomfortable? "No, it's something I have got used to now."

Amlani, who also has a club called Mocha Bikers' Association, often heads to places outside Mumbai with his club buddies, also sometimes going it alone.

But he doesn't find Mumbai ideal for biking and often comes to Delhi just to cruise around. Whenever in Delhi, he makes it a point to go riding the Delhi Noida Direct flyway even though he insists, "I never ride above 80 kmph or so."

Ananad Adkoli, CEO, Liqwid Krystals, a Bangalore-based IT firm, is actually a qualified biking instructor, and his love for biking began at the age of 13. "I was not allowed to ride one but still used to sneak out," he says.

From being an illegal biker to a qualified trainer in the US, he has evolved through various stages of biking. He has had superbikes like Kawasaki Ninja and also rode a Harley at one time, but has since moved on to vintage bikes. A 1954 BSA Triumph is the bike he currently rides.

Amlani too says he is in the market for a vintage bike, though he would never part, he insists, with his Boulevard. Adkoli says that he has done his share of sharp turns and speed thrills but, with age, has mellowed down. But his passion for biking remains strong.

What about family pressures, or work schedules, don't they get in the way of these biking enthusiasts? "Yes, they do, but I didn't buy or ride my Harley to go on long rides. It's for me and any time spent riding is quality time," says Damania.

For 42-year-old Adkoli, ever since his son was born, this quality time has reduced to a half-day in a month when he heads off towards the Nilgiri Hills near Bangalore. Ansal's two bikes were gifted to him by his wife.

Even though he is part of a few biking clubs and also runs a bikers theme restaurant called Road Trip in Bangalore, Amlani goes on biking trips with his group of fellow bikers on the Mumbai-Pune highway.

Isn't maintenance a headache for a bike like the Harley, or Amlani's Boulevard? "When you love your bike, you automatically take care of it," says Amlani. Of course, it helps if you know the basic technical know-how which, in his case, he does. Damania rarely takes his Harley Davidsons out on long rides so all his VRod requires is "routine polishing and cleaning", he says.

Ansal points out that though he is about to turn 50, he is looking forward to spending more time biking than he has ever done before in his life. Damania is content riding his Harleys in the city but says it makes him feel so much better just to be saddled in one. Amlani, the youngest of the lot, aims to continue biking for as long as he can. And for Mistry, it's "a part of my life" and not something for which he has to take out time.

Nor are these the only names in the marquee that light up when talk veers around to middle-aged bikers. There are enough well known industrialists and entrepreneurs who have superbikes gleaming in their garages, but as it becomes somewhat easier to bring in bikes into the country, a slew of wealthy Indians are vrooming out on the highways to give vent to their passion for superbiking. Mind how you drive out of town this weekend - you don't want to get in their way.