The West Point Bridge Designer 2010 is in the public domain. You may download the software from our web site (http://bridgecontest.usma.edu) free of charge; you may make as many copies as you like; and you may distribute it to others without requesting permission.
The West Point Bridge Designer 2010 is intended for educational use only. Development and distribution of the software does not constitute endorsement by the U. S. Government, the Department of the Army, or the United States Military Academy of any design. Use of the software for commercial or construction purposes is prohibited.
To understand why the West Point Bridge Designer 2010 would not be an appropriate tool for designing a real bridge, see What is Not Realistic about WPBD.
If you need to design a real bridge, you must obtain the services of a registered professional civil engineer. To do anything less would be irresponsible.