This group of riders has created...
This group of riders has created a potentially dangerous situation for themselves. If one of those drivers in the left lane wants to get off at the exit they are passing, he may try to move through the line of motorcycles, with disastrous results. It's best to break such a large group into smaller groups of four to six bikes and separate them from each other so that cars and trucks can pass through their lane from side to side.
I was motoring along southbound on a four-lane Oregon road, barely overtaking another motorcyclist who I'd first seen over a quarter-mile ahead of me. By now the distance had shrunk by about two-thirds and, even over the wind noise I could tell from the considerable rumble that he was riding a big twin. I was still a few hundred feet behind when he gradually overtook a van towing a big house trailer. This rider had been favoring the right side of the lane, and when he got right up behind the trailer, he made a quick flick into the left lane, again on the right side, close to the van-trailer. It was going almost as fast as we were, and I could hear that he didn't accelerate when he drew alongside of it. He had probably been in passing position for almost a minute when the van-trailer signaled, then began to move over (a deer carcass lay in the road ahead). The rider apparently didn't see the signal and didn't react until the vehicle began crowding him. Then he pulled ahead next to the driver and gestured angrily. I saw the brake lights on the trailer, then the bike, illuminate, as the rider apparently tried to stay next to the vehicle as it braked. But the driver still had the obstacle to avoid and continued to move over while trying to brake to get behind the bike. The rider wanted to express his anger though and didn't get out of the way until he was finally on the shoulder, and both he and the other vehicle had slowed to less than 30 mph, and I'd had to brake to stay clear.
It was probably the worst pass I've ever seen. The rider was probably used to being heard by other drivers, and I don't know why he didn't see the van signal (he was ahead of the trailer and maybe the signal on the van itself wasn't working or visible). But he did almost everything he could to get into trouble. He and his bike were dull colors (black and blue, respectively and appropriately), his lights were not on, he stayed close to the vehicle he was passing, perhaps in a blind spot. Relying on loud pipes didn't work either, maybe because the van was loaded with several people and music was playing loudly.
Passing other vehicles is one of those things we do routinely and rarely think twice about, but there is always danger there. It seems that at least once a week I read about motorcyclists killed when other cars (or motorcycles) cross the centerline and hit them. And I can't help but believe that some of those "single-vehicle" fatal accidents where a rider runs off the road and crashes for no apparent reason are caused by another driver that he dodged before he crashed. There was just nobody else there to see it. Cars cross centerlines unexpectedly because their drivers are drunk or distracted or don't see the oncoming bike.
You can't do anything about keeping other drivers from getting wasted or answering the phone, but you can make yourself visible and easy to pick out from your surroundings. In particular make sure your headlight is working and that you use the high beam during daytime. That high beam not only makes you appear closer, but it can also separate you from the car behind you with its headlights on. Your headlight your headlight is particularly likely get lost in those of the cars behind you near dawn or dusk, leaving an oncoming driver unable to see you when he decides to pass. If you have driving lights or spotlights, this is a good time to use them. Your high beam or other forward lighting can also help a driver that you are overtaking identify you in his mirror before he changes lanes. During midday, bright, solid colors on your helmet and jacket are probably most effective in making you conspicuous.
Overtaking another car usually involves passing through the driver's blind spot, and making yourself conspicuous will help him see you before you hide there. However, you can also protect yourself by accelerating as you come alongside to minimize exposure time and by moving away from him, perhaps to a more distant lane, as you pass. And if you want to be heard, a good horn (which projects its warning in the right direction) is more friendly and effective than loud pipes.
You can often predict when a driver is likely to move into a different lane on a multi-lane road by watching traffic ahead of and around him. If he is overtaking a slower car or cars up ahead in his lane are slowing, you can expect him to jump lanes. Cars also tend to change lanes when following a large vehicle they can't see past. Sometimes these slower vehicles catch them by surprise, making them more likely to lane-leap without fullu checking thier blind spots. You can teach yourself to predict these events with a little practice and by payuing attention to what's happening way up ahead.
Distracted drivers sometimes move over unintentionally and won't always correct because they don't recognize that someone is beside them. So drivers talking on cell phones, applying make-up, or holding a large cup in their steering hands should be given a wide berth. Even undistracted drivers don't always take a real look before they move.
Here in Southern California the only drivers who signal lane changes are a) tourists, b) safety freaks, c) those who forgot to cancel their signal after starting the car that morning, or d) folks who believe that signaling legally entitles them to change lanes without looking, because, hey, they have like given fair warning that they are coming, dude. There are also those who cross the line and then begin to signal about halfway into the next lane. In any event, turn signals are not always meaningful indicators of what the driver actually plans to do (unless the car has Iowa plates). A shift of hands on the wheel, a slight turn or the head, or a slight drift from the lane position thay have been holding are sometimes the only indication that they are coming your way.
But the strategy for passing all these sorts of drivers is the same. Minimize your time next to them, particularly in their blind spots, and stay wide (on the far side of your lane) as you do. This applies to two-lane roads as well as those with more than one lane going your way. There may seem to be no reason for a driver you are passing on a two-lane road to cross the centerline, but be ready anyway—they might just be unaware you are there and drift across. In particular, be wary if a vehicle you are overtaking begins to slow as you pull out. He could be making your pass easier or he could be preparing to turn into a drive you haven't seen on the left. I have heard of several riders who were taken down by this scenario.
The driveway or road on the left could also hold a vehicle that is planning to turn out onto the road opposite your direction of travel. It is something to consider and look for before you commit to passing.
Still, the likeliest source of danger is the car you are passing, so the best set-up for passing on a two-lane road is try to ride in a position where the driver can see you in the mirror while you wait for a safe opportunity to pass. Signal before you start to accelerate, pull into the left side of the left lane as you pass, keep an eye on the car you are passing as well as potential sources of conflicts (he is more likely to run you off the road than to collide with a vehicle that pulls out from the right, for example), and continue to accelerate after you are ahead of him to open up a gap.
This is definitely the time to use all that power you paid for. Downshift a gear or three before you start to pass and rev it to the max before each shift. The reasons you want to open up a gap between the car you're passing and yourself are 1) slowing down right in front of him is likely to annoy the driver, 2) opening a gap gives you a cushion if you have to brake for an obstacle up the road, and 3) it "sells" the pass—the driver isn't likely to think about re-passing you. If other riders are behind you, the gap you create should be even larger so they have enough room to pull back into the right lane and still leave a gap.
On busy four-lane roads, you want to make a quick pass because there are likely to be faster vehicles overtaking you in that left lane. Going past a long truck at 0.5 mph faster than its speed while traffic backs up behind you and then taking your time to get back in the right lane is asking for trouble and creates potential conflicts. You may have to go faster than you like for a quarter-mile or so, but do it anyway. And when you are done passing, get the hell out of the way and back in the right lane even if traffic isn't stacking up behind you. Even if you are the fastest vehicle on the road, staying in the left lane simply advertises that fact to the cops.
What about overtaking a slower vehicle that won't get out of the left lane on a four-lane road? The potential for a driver to move over into you as you pass him on the right is greater than when you pass on the left, and if you come up behind them and give up on him changing back to the right, wait a few seconds after you move to the right before you accelerate to pass to be sure he hasn't recognized that you want to pass and decided to move over. Other than that, the standard rules apply: be conspicuous, avoid blind spots, accelerate hard, and ride wide to give you a cushion as you pass.
You need to get out of the way any time you are holding up traffic behind you. If you don't let them by, the vehicles you are holding up may get impatient and make an unsafe pass that takes you out. On a two-lane, I pull over whenever I have more than two vehicles behind me waiting to pass and I can do so safely. And when a vehicle pulls out to pass me on a two-lane road, I slow down and move to the right to minimize the passing time and potential for contact. I slow down even more when the vehicle passing me looks like he might have cut it tight and could come back into the right lane before has completely passed. However, I am careful not to invite the vehicle behind that one to pass unless I am comfortable that it can do so safely. There are also times when it seems prudent to speed up until I can safely move over.
If a vehicle passing you starts to move right while still next to you, it's no time to get territorial. Brake hard (unless another vehicle is breathing down your sissybar) and move right. Ride on the shoulder if there is one. Get indignant later; get out of the way now. You have a nice narrow cross-section, so take advantage of it.
Being narrow can also serve you if you find yourself in that most horrifying of situations—passing a car on a two-lane when another one appears up close going the opposite direction. Crowd right up against the car you are passing and hope that it and the other car move over enough that you don't clip the on-comer. It is less dangerous to stuff yourself against the car you were passing than to barely nick the one with a 120-mph speed differential. The good news is that, on most two-lane roads, there is enough space to do this. I have seen it done on several occasions on U.S. roads. In some parts of the world, riders do it routinely and other drivers just move over and let them through.
Passing errors that would be mild fender-benders if two cars are involved can be fatal when one of the vehicles is a motorcycle. But if you help other drivers see you and minimize their chances to connect by staying alert and using your bike's size and acceleration, you might make all your passes uneventful.