With Park Boulevard being rerouted in 2016, a segment of old Park Boulevard was abandoned that is adjacent the main entrance of Hersheypark.
Since early April, a bunch of markers have appeared on this part of old Park Boulevard.
The updates to this area are pretty historically significant given that Hershey Park Pool, Starlight Ballroom, and Hershey Creamery Model Dairy used to be in this area.

With all of the markers you can see in the articles posted about this, each color has a different representation.
An example of a marker can be seen in the image below.

This is a UGI Energy Services, Inc., 4 inch gas line, originally installed in 1979. The marker is yellow, representing the category a gas line would belong. Other yellow markers could represent oil, steam, petroleum, or other gaseous materials.
Here is Pennsylvania’s Temporary Marking Guidelines, which are identical to other states.

Here are list of articles related to these updates:
- Hersheypark Update | April 15, 2017
- Hersheypark Update | April 30, 2017
- Hersheypark Update | May 15, 2017
- Hersheypark Update | June 1, 2017
- Hersheypark Update | June 15, 2017
- Hersheypark Update | July 1, 2017
- Hersheypark Update | July 15, 2017
- Hersheypark Update | August 1, 2017
- Hersheypark Update | August 15, 2017