[Craig McClure]

While driving in very heavy rush hour traffic in Venice Fl today, I heard the familiar deep rumble of a Harley approaching my vehicle from behind. He was in the next lane ,2 cars back. My observation was that his noise would likely keep anyone from changing lanes without having a look for the source of the ruckus first. Correct me if I'm wrong, A rider with loud pipes would need to be approaching the speed of sound before outrunning the exhausts announcement of his presence.

[Arizoni]

Well, your right about having to go the speed of sound to get somewhere faster than the sound will but I'm not sure any motorist can be counted on to check out the source of the noise before changing lanes.

In fact, I know of people who just get pissed off when they hear loud pipes.  Especially if the loud pipes are coming from a big V-twin.
These people get ideas like, "I'll be damned if I'm going to let that noisy SOB get along side of me!"
I know I sometimes have that same thought when I hear a car with a 10,000 watt speaker system in their car and they are playing "rap music" and their whole car is going "WUMP, WUMP, WUMP".

Seriously, cage drivers have their windows rolled up, the reefer on and they are talking to someone on the phone while they play with the GPS screen. 
Anyone who thinks they are actually paying attention to what's around them can end up in a heap of hurt real fast.

[mattsz]

While driving in very heavy rush hour traffic in Venice Fl today, I heard the familiar deep rumble of a Harley approaching my vehicle from behind. He was in the next lane ,2 cars back. My observation was that his noise would likely keep anyone from changing lanes without having a look for the source of the ruckus first. Correct me if I'm wrong, A rider with loud pipes would need to be approaching the speed of sound before outrunning the exhausts announcement of his presence.

The noise probably would keep you from changing lanes - you're one of the enlightened!

I'm with Arizoni on this one...

[no bs]

if they can't see me, they'll certainly hear me.

[NorEaster]

If they can hear you it doesn't necessarily mean that they will care... 
damn cagers 

[no bs]

the 5 normal senses are sight,hearing, smell, taste, and touch. there are more including common, horse, and nonsense(non-sense?). more than a few lack any combination thereof.

[Scotty Brown]

I have a rider friend who claims to be a Mouse in a field of Cats when driving in traffic.  He claims it is up to him not to let the Cats pounce as they are only doing what is instinctive to them.  Really doesn't make a lot of difference on the noise of pipes is one is paying close attention to ones surroundings.  The other analogy is a Cat in a room full of rocking chairs.  Be aware, be very aware.

[Roeland]

Perhaps, but a loud (very loud) pipe does help - I use it regularly and blib the throttle if I see ignorant motorist - it works...

[azcatfan]

My flow through muffler gets pretty loud when I'm working my way through the gears, at idle or cruising it is not bad at all.

That being said, I've actually seen people's awareness of me increase while plodding down the road.  I've seen their heads start looking for me because they heard me first. 

At idle, my valves tell them where I'm at B-)

[GreenMachine]

 I've seen their heads start looking for me because they heard me first. 

Same for me when riding my Yamaha v twin 1100...I do throttle off  driving thru subdivisions or in town  as I don't want to be seen as a nuisance by the police/Not that they are enforcing a noise ordinance yet but why tempted them.. The open Brit style pipe setup on Greenmachine isn't nearly as loud and I have no concerns blipping its  throttle..Nothing wrong with  OEM setups either but I do notice when taking a walk down the street,  a few hybrid cars have been so quiet that I never hear them from behind ...Best I turn around to keep a eye open for those them . Hate to be taken out by a Prius..GM
 

[mattsz]

Hate to be taken out by a Prius..

The newer ones actually have a device installed that makes noise when the car is driving slowly under electric power alone - strictly to warn pedestrians...

[NorEaster]

I feel its best to drive this way 

[heloego]

Now to find a reasonably priced Thompson. 

[Russ]

"Thompson" ? You realize "Enfield" made rifles too

[High On Octane]

I feel its best to drive this way 

I feel like riding that way and pulling the trigger will quickly put you into a death wobble!