Illustration on Web Accessibility Success Criteria 2.3.1 - Three Flashes or Below Threshold

Before Rectification

WARNING!

The next webpage has a large flashing image, which may cause problems for people who have epilepsy.
 

The traffic light is flashing too fast and covers a large part of the screen. The flashing image may cause problems for people who have epilepsy.

After Rectification

Using Green Man Crossings Green man crossings are pedestrian crossings with traffic lights to signal drivers to stop, and pedestrian lights to signal pedestrians when to cross.

The size of the flashing image has been reduced  to a small portion of the screen only and the image only flashes three times in any one second period.