www time limits and traffic control

[Anne Christensen]

Please excuse the cross-posting.

I need help with traffic control.  Here's the big picture:

We currently have 15 public PCs on a LAN.  They access our library
catalog, 27 CD-Rom Databases, 10 subscription databases which we receive
via the internet, and full graphic WWW access.  We also have a great
number of dumb terminals throughout the building which access the
library catalog and character-cell versions of the subscription databases.  

For the 15 public PCs on the LAN we have had to go to a sign-in procedure.
Early on, we learned that our volume was too great to take i.d.  We do,
however, issue small slips with the *beginning* time for the user on that
workstation.  The same time is then jotted on a chart at the General
Reference Desk.  Everyone gets at least 1/2 hour.  They are welcome to
stay longer if no one else is waiting.  Once you are bumped, you must wait
at least 20 minutes before getting in line to sign up again.  We currently
have no daily time limit, but it's starting to get tempting!

This is the best we've been able to come up with so far.  Our problems
include the following:

Monopolization of electronic resources by a number of patrons with
"unique" hobbies, lifestyles, and behavioral problems (not necessarily
related to the internet but certainly enhanced by it.)

Staff burnout in spending hours each day resolving petty squabbles among
users.

I'm asking for your help in finding alternate methods of traffic control.
Does anyone out there use a different type of registration?  
Do you have different time limits/registration procedures for different
types of products?
Have you found an electronic way of limiting abusive resource users?

All input is welcome!  You may reply to me and I'll summarize for the
group or post here.  Thanks!

Anne Christensen
Librarian II
Phoenix Public Library
achriste at lib.ci.phoenix.az.us