SVG Animation Pattern - Traffic Light

I want to animate a repeating traffic light just like in real life. I am changing the opacity from dark to brighter to display which light is on. Which works but it doesn't repeat.

Solution 1:

You've multiple elements with the same id which is invalid. After fixing that you can target the animation end correctly e.g.

<rect id="stoplight" x="30" y="0" height="308" width="100"></rect>
<rect id="redlight" x="55" y="25" height="60" width="50"></rect>
<animate xlink:href="#redlight" id="redlight2" attributeName="opacity" from=".3" to="1" dur="2s" begin="0s;greenlight2.end"/>
<rect id="yellowlight" x="55" y="125" height="60" width="50"></rect> 
<animate xlink:href="#yellowlight" id="yellowlight2" attributeName="opacity" from=".3" to="1" dur="2s" begin="2s"/>
<rect id="greenlight" x="55" y="225" height="60" width="50"></rect>
<animate xlink:href="#greenlight" id="greenlight2" attributeName="opacity" from=".3" to="1" dur="2s" begin="4s" />