Motor vehicle crashes with cyclists are on the rise, with a six percent increase in fatal crashes from 2006 to 2015. Although some research exists on the perception-response time (PRT) of drivers to some types of path intrusions, data on the perception-response of through drivers to cyclists who fail to stop at a stop sign, and ride into the path of a vehicle has not been researched. The purpose of this study was to quantify driver PRT to a cyclist that intrudes perpendicularly in front of a through vehicle at an intersection where the driver has the right-of-way. PRT is defined as the time from when the cyclist is at the stop sign until the driver reacts, whether by touching the brake pedal, swerving (steering wheel angle change of at least 2 degrees), accelerating, or a mixture of those responses. 52 (NFemale=26; NMale=26) licensed volunteer drivers participated in the study conducted at the University of Guelph Driving Research in Virtual Environments (DRiVE) lab using an Oktal complete vehicle driving simulator. After a brief practice drive to acclimatize to the virtual environment, participants completed the approximately 10 minute experiment drive during which the cyclist hazard was presented. About one quarter of drivers crashed into the cyclist, with a mean time-to-impact of 3.26 seconds. Female drivers had significantly slower reaction times than male drivers, although there were no differences in crash rates.