Well, you could use any P2P software like Kaaza, Ares, Limewire, etc to download it. Just download the softwares, install and search within them. Torrents would rarely help you for not so popular softwares.
But one should respect the amount of work the developers of Transcad have put in to the software. They rightfully deserves some monetary compensation for her work, which you would not be paying in that case. Also, It is illegal. In the end, you are a better judge. This is all I can say.