I equipped my truck with a triple horn that sounds a lot like the ones
used by the race official's cars in the TdF. Cyclists recognize it as a
friendly acknowledgement regardless of how long I hold it :-3).

Of course, when tooting at cyclists I always wait until I've passed or
am approaching, so's not to startle them.

- -
Compliments of:
"Your Friendly Neighborhood Wheelman"

If you want to E-mail me use:
ChrisZCorner "at" webtv "dot" net

My website:
http://geocities.com/czcorner