Freeway Crossing

Freeway Crossing running on a real IMLAC PDS-1

Around 1971, student programmer Michael Irrgang wrote a game called Freeway Crossing. He made it for Dr Earl Hunt for use in a psychological study at University of Washington involving reaction times. The game runs on an early version of the IMLAC PDS-1 - the so-called "Alpha machine". The code was assembled using punched cards on an XDS Sigma 5 at the Computer Science department.

The object of the game is to run a car vertically up the display without being hit by any of the six cars running horizontally. This game was probably the first in the genre typically exemplified by the Frogger arcade game.

External links

• Assembly listing
• Scanned listing transcribed into text
• The game running on an emulator
• The game running on a real IMLAC PDS-1
• Paper by Earl Hunt describing the UofW CS facilities, including the Sigma 5 used to assemble the game, and the newly installed IMLAC PDS-1.