A group of very attractive young female city employees discovered they could nicely supplement their income by moonlighting as call girls. One of the girls discovered she was more successful as a blonde after having her hair bleached. She convinced the others that the old saying, "Blondes have more fun," is true.
The ladies became so popular that they were able to charge exorbitant rates. They even charged their taxi fares to the Johns they served.
When hard times bit and the market got soft, they needed a bigger come-on. Some of them understood the economic law of supply and demand, so decided to lower their rates. They decided not to include taxi fares in the fees they charged their customers.
They have become known as: The taxi-free municipal blondes.