Final answer:
The 'SLOWER TRAFFIC KEEP RIGHT' sign is intended for multilane highways and advises slower drivers to use the rightmost lane, enabling better traffic flow and allowing faster vehicles to overtake on the left.
Step-by-step explanation:
The sign 'SLOWER TRAFFIC KEEP RIGHT' is a traffic directive used on multilane highways indicating that vehicles traveling below the average speed of traffic should stay in the right-most lane. This practice helps facilitate the smoother flow of traffic, allowing faster-moving vehicles to pass on the left. It is also a legal requirement in many areas for slower-moving vehicles to move to the right when they are being approached from behind by faster traffic, even if they are traveling at the posted speed limit. It is important to note that there are both de jure speed limits, which are the legal limits posted on signs, and de facto speed limits, which refer to the speeds at which drivers actually travel, influenced by various factors including the likelihood of enforcement by police.
Ignoring these rules can lead to traffic congestion and can be considered discourteous to other drivers. In some cases, driving significantly below the speed limit—referred to colloquially in the scenario as 'DWE', or 'driving while elderly'—can create frustration among other drivers, as illustrated in the example with Peter getting stuck behind a slow-moving vehicle.