A few days ago I was nearly in a serious car accident. A woman in a Fiat Punto was displaying the sort of aggressive driving that would make a nun angry; she swerved across three lanes of traffic at the last possible moment to leave at a junction, drawing a honking chorus of horns from the enraged drivers behind her. She's almost disappeared from view when I caught sight of a little symbol glimmering in the sunlight on her boot. It was a fish sticker – worse still, one that encased the word 'Jesus'.

It may come as something of a shock that some Christians turn out to be terrible drivers. In fact in my experience, there seems to be some kind of weird correlation between faithful people who drive like someone has spiked their communion wine, and owners of said aquatic accessory.

The Ichthys fish symbol was first used as a secret sign among the early church, but in the 1970s it enjoyed a popular culture revival. Most prominently, Christians chose to display the stickers on the rear bumpers or boots of their cars. Their popularity (and that of parodies including a fish with legs containing the word 'Darwin') has endured ever since, but my near-death experience has led me to wonder: isn't it time we retired this slightly odd piece of Christian memorabilia?

We might think it's a great way of marking our Christian distinctiveness, but...

It is much more likely to be a terrible witness. While much of evangelical Christianity's jargon has disappeared from the cultural lexicon, most drivers know exactly what that little fish means. And while they're unlikely to care very much about it while you're driving at the speed limit, you can bet they'll notice when you cut them up, hog the middle lane or park across two spaces at the supermarket. Do we really need to give people more reasons to think Christians are hypocrites?

They con us into thinking we're sharing our faith. Putting a fish sticker on your car might feel like a subtle way of putting your faith 'out there', but I think it can dupe us into believing that we're somehow evangelising. To my knowledge, no-one has ever endured a road-to-Damascus moment on the hard shoulder of the M1 after glimpsing a plastic fish on the boot of a Toyota Prius.

They make us look unnecessarily weird. We're already seen as something of a cultural irrelevance, and putting odd-shaped stickers on our cars does little to help. Instead of appearing like the sort of people you could be friends with and welcomed among, the trappings of a sub-culture make us seem separate and strange. When you get to know us, some of us do strange things like speak in a language that sounds like Klingon or grip hold of people's injuries while calling down divine healing. We're weird enough without the addition of bizarre car ornaments.

If the lady who cut across me earlier this week had been Ichthys-free, I'd simply have shaken my fist a bit, maybe chuntered like disgraced Top Gear presenter, and then forgotten about her. Instead, I saw her proud pronouncement of Jesus at the very moment that she nearly sent me to meet him.

We no longer need a secret sign to communicate our faith to each other, least of all our brother and sisters in Christ who we're currently cutting up. It's time to ditch the fish, to share our faith in more honest and less weird ways, and for some of us, consider driving a little more safely.

Martin Saunders is a Contributing Editor for Christian Today and the Deputy CEO of Youthscape. You can follow him on Twitter: @martinsaunders