A traffic calming measure in the road is an indicator to drivers to:

Traffic calming measures are designed to enhance road safety and encourage more careful driving behaviors. These measures, which can include speed bumps, chicanes, raised crosswalks, or narrower lanes, serve as a physical indication to drivers that they should reduce their speed.

When drivers encounter these features, they are reminded that they are entering a zone where there may be pedestrians, cyclists, or other road users, and thus, a more cautious approach is necessary. The purpose of such measures is to create a safer environment, particularly in residential areas, school zones, or areas with high foot traffic, where higher speeds could lead to accidents or injuries.

The other options do not align with the intent of traffic calming measures. Increasing speed, changing lanes, or making U-turns would contradict the goal of promoting safety and caution in driving.