Opinion: Steven Downes looks at the perils and pitfalls of sharing a lift.

I'm a green warrior, fighting quietly to save the planet.

When my grey bin goes out every other Tuesday, it's virtually empty. My heating is on a smart meter - not that I have it on very often.

I don't own a car and neither my bicycle nor my legs create any pollution.

But there are limits to my humble efforts: I won't share a lift.

I don't mean that I won't get in an elevator, even though I hate the weird British way that we stand in awkward silence - a bit like men standing at urinals.

What I mean is that I couldn't bring myself to sign up to Liftshare and get into a car with somebody I don't know.

At this point, I have to make it clear that I have total admiration for Liftshare the business, which is a great scheme that Norwich and Norfolk can be proud of.

But for me it is a bit like signing up to a dating website, where you look for the right match: on the one side, you're hunting for a woman who shares your love for PG Wodehouse and scrambled eggs with salad cream, on the other it's the quest for a driver who's going from Norwich to Three Holes on Tuesday at 6am.

As someone who doesn't like uncertainty, there are just too many imponderables when you open the passenger door and get in.

- What radio station will the driver like? Radio Four is fine, Radio One is bearable, Radio Norfolk doesn't offend. But if I had to endure Kiss FM or Steve 'let me just read out a letter from someone who says I'm great' Wright, I'd have to bale out while the car was moving.

- Would they share my music taste: a bit of Hendrix, Zeppelin, Dinosaur Jr or Johnny Cash? It's highly doubtful. Knowing my luck, I'd be trapped in a child-locked car with a Justin Bieber soundtrack.

- The driver might be a dog owner. I am no fan of dogs and particularly dislike getting their hairs on my clothes.

- The driving style is unlikely to live up to my exacting requirements. It'd be too fast, too slow, too indecisive, too reckless, one hand on the wheel, too close to the steering wheel - in essence, not me driving.

- Finally, horror of horrors, what about the conversation? I hate making small talk or big talk, but also cannot bear awkward silence. Really, I'm a bit unsociable. When I'm in a car, I like it to be me, my audio book and my thoughts.

There are too many other places where I'm forced to converse with human beings other than those people who have know me for long enough to shrug off my shortcomings.

Shops, restaurants, football matches, buses, doctors' waiting rooms... the ordeals are endless.

Picking a random card from the deck of Liftshare drivers would only add to my stress, so I'll give those who do so an admiring headlight flash - but swerve it myself.