Lane-splitting - riding between lines of stationary or slow-moving cars - is one of the advantages of riding a motorcycle. It saves time but, more importantly, saves lives. But, is it safe and legal?

There are few things as satisfying as coming across full-on traffic-jam queues of cars and trucks on a two- or three-lane highway on your motorbike. Given that a bike is three or four times narrower than any car or truck, there will be gaps between the lines of traffic that you can thread through to get to the front of the queue and onto the open road once more.

There are two problems, however: is it legal and is it safe?

As for the legal issue, that all depends where you live. Utah and Montana have both legalised the practice and Arizona is about to do the same. Arizona will allow riders to cruise slowly between lanes at speeds no faster than 15 mph if the other vehicles are stopped. Modelled off Utah’s legislation, the practice can only be done on roads posted at 45 mph or less. It does not allow riders to pass on the shoulder or on the median.

So, the answer to the question of legality is: depends where you live. Outside of the U.S., some countries allow it, some don't.

The question of safety is completely different. To be completely safe, lane-splitting requires all road users to be courteous and accommodating towards each other, which doesn't always happen.

There can be no question that allowing a bike to filter through traffic queues reduces the risk of being rear-ended by an unobservant car or truck driver, with predictably disastrous results.

So, from that point of view, it is safe. But you know the old saying: give them an inch and they'll take a mile? That applies to motorcyclists. It's one thing to filter between lanes of stationary traffic and quite another to filter through two lanes of moving vehicles. When traffic is moving, the drivers will be looking for any advantage, changing lanes at a moment's notice to benefit from one lane moving slightly quicker than the other. When this happens, the glance in the mirror is rarely long enough.

But it's not all the driver's fault. Some motorcyclists filter far too fast: a driver might look in his or her mirror and see the road clear behind. By the time he makes the manoeuvre, the fast-moving bike might be upon him. You can guess the rest.

The only answer is to use your own judgement and discretion. Even if you filter at 5mph faster than the queue of traffic is moving, you will still get to where you are going much quicker than the car driver, especially if the queue is long.

Just don't expect the jealous car drivers to like it and get out of your way!

For more information, see this website