Never. If there are no other options, lay the bike down. This will slow you down quickly and can offer some protection in a collision. It will hurt, but if your body becomes a projectile in the air, travelling in the same general direction and close to the same speed as the motorcycle, you are liable to far more serious injuries. ------------------------------------------------------------ Re: "don't jump off & don't lay the bike down" Personally I'd rather take my chances with the pavement all the same. It usually causes less damage than trying to go through or fly over a car. That said, the brutal truth is that you seldom have time to decide. Most accidents happen on urban streets at moderate speeds, within a short distance of your home. What? Bang! My experiences have included: - Losing control and landing in a ditch, because the driver of a car didn't see me in the intersection. - Flying over the trunk of a car after it unexpectedly stopped in the middle of the street in my path. I was looking to the right and left while crossing a set of railway tracks an instant before this happened. - Being struck from behind at an intersection, moments after the light turned green (hit and run). The driver of the other car was travelling well above the speed limit and far too fast to have stopped at the light. - Losing control and going down after a car made a sudden left turn from the right lane in my path, without looking or signaling. I was lucky: a cop saw the incident from across the street. - Losing control and going down after hitting a bicycle that had made a sudden left turn in my path, without looking or signaling. This was at slow speed, on new pavement in a light rain: it was like trying to stop on ice. My only consolation was that the bicycle was a write-off. Oh, the joys of urban driving. And helmets do help, though there are plenty of folks who seem to prefer travelling through a car head first rather than helmet first.

You should stay on the bike for as long as possible so that you can apply the brakes for as long as possible. ("Laying down" the bike will make the point of impact much faster than on the brakes, since bikes slide quite easily on their sides.) If, despite the braking, you still have a high closing speed, it's worth jumping off. At the last possible moment brace yourself against the footpegs and aim to jump as high as you can straight upwards. I have heard of a case where a rider and pillion both did this when someone pulled out across them and they both got away with it.

No you shouldn't jump off. Consideration of what circumstances could arise that could make it appropriate to lay a bike down is also needed, as this case is very rare. Jumping off, or laying it down is giving up control of the machine, a decision not to be taken lightly, you want to keep control as long as possible, especially if the controlled act is locking up the brakes. The conventional wisdom is to stay on the bike and keep it upright for as long as possible, the only time laying a bike down is accceptable is during instances relating to overhead hazards, such as going under a semi, and even then the time it takes to get the bike on the ground maybe better served in slowing the bike down as agressively as possible and "falling off" at the last possible second. Rubber against pavement is the most effective way of slowing down a bike, metal will slide quite effectively and offer little resistance, we're talking about fractions of seconds here, and a fraction of a second could mean quite a few MPH of speed reduction, when hard on the brake. You're hitting the object anyway, it's just as well to be upright, and braking, up until the moment of impact. I can't see being able to effectivly brake hard while preparing to jump off, you've really got to lean in. In any event when talking about excessive speeds, you may only be determening whether or not the ceremony has an open or closed casket. It's tough to know if you will have your wits about you enough to make the proper decision in the split second (hopefully) available to you as every scenario is different, having different scenarios considered will improve your ability to make the proper decision, should a situation arise. As mentioned in another answer, the time to make a decision is a luxury most are not granted, be careful, watch out for the other guy & watch you speed.

Motorcycles riders should always wear leather clothing. If an imminent crash is about to occur, departing the bike may be your only life-saving measure. Hitting the pavement or ground is why you wear the leather. It is a buffer between you and the elements. Leather also serves as a sliding buffer. Bare skin hitting the pavement is like peeling a potato. Leather is your life preserver.