Sorry man, didn't know it was you!
Actually I'm probably the slowest (driving) wrecker driver in Houston - I'm an adult, I've got babys that count on me, and I also don't want to hurt anyone (and I can't stand reckless drivers of any type - cars don't kill, reckless drivers do).
But to answer your question here it is in a nutshell:
Wrecker driver sits and listens to anywhere from 6 to 12 EMS radios.
(I've got HPD Central, South Central, Special Ops (downtown patrol + accident units), HFD, Harris County Constable Pct. 7, and Metro PD.
When one of the above units is dispatched a call that the wrecker driver thinks may result in a tow, (like a wreck or an arrest) the wrecker driver trys to get there first, or at least before the LEO gets there and picks up his or her mic. and says the phrase, "no more wreckers".
Those that made it then "gamble" to see who gets the tow.
We have brass "chips", (round, flat "coins", actually key tags) printed with one's choice of text or #s on one side and "blank" on the other.
One driver takes all the chips, shakes them up in his hands like dice (or just tosses them into the air) and when they hit the ground the odd man out wins (like all are face down except one - the winner).
Or the chips are put in a hat and one is drawn by a bystander.
FWIW these are just Houston's methods, and totally "gentlemens agreement" - the city ordinance states that the first wrecker to arrive gets the tow. Our great city is often referred to as "the last of the wildwest" in the trade magazines.
In regards to the driving habits you mentioned - theres no excuse for it, and people get hurt or killed every year or so, just because some jerk wanted to beat everybody else to a tow.
This crazyness is drying up - new regulations and LEOs are cracking down on this behaviour (and let me tell you its been a long time coming!!!).
In other cities they work off rotation lists but it's been said that with Houston's volume of tows we would have accidents tying up roads for hours everyday - as crazy as our system is it works - but it would work just as well with the crazy wrecker driving part eliminated, IMHO.
Well, thats it for this rant - perhaps later (after some good 'ol fashioned wrecker driver bashing) I can post some of the good stuff - I think part of what keeps a lot of us out here is the chances to help folks out - (like when my wife and I saved a man from a burning house by yanking the burglar bars off with a chain, or winching the near drowning victim up the freeway wall during Tropical Storm Allison) :)