Detained On Side Of Highway While Officer Left To Pursue Another Traffic Violator

I was pulled over and issued a speeding ticket. The officer took my licence and told me to sit and wait on the side of the highway while he then took off to persue another traveller and issue another ticket while I waited on the side of the highway for him to return 20 minutes later. No protection from flashing lights. I was in an area where I couldn't even be completely pulled off the road and risked being hit by oncoming traffic. I know there are rights you have while being detained or arrested, and I receive none of these. Has anyone ever experienced this while being pulled over for speeding?