On peak weekends in town, it is not possible to get a cab in a timely fashion. 526 cabs cannot handle the size. Having more cabs on the road will do two things: lower fares and improve service. How so? Competition. Instead of having a virtual monopoly on service, cab drivers and companies will be forced to improve their businesses.
The other direct effect that more taxis will have is to decrease drunk driving. When alternative transportation is either expensive or not readily available, an intoxicated person has one other reason to choose to drive himself. This is a public safety issue - one which can be easily rectified by either granting these additional licenses or overhauling the entire Metro taxi system to accomodate an unlimited number of taxis.