What is the speed limit in a residential area unless posted otherwise?

In Illinois, the speed limit in a residential area, unless otherwise posted, is 25 mph. This standard is set to enhance safety for residents, particularly for children and pedestrians who may be walking or playing in these neighborhoods.

The rationale for this speed limit is to minimize the risk of accidents and injuries. Residential areas typically have more foot traffic and are often designed with narrower streets, driveways, and intersections that can present unexpected hazards. By enforcing a 25 mph limit, drivers are given a reasonable opportunity to react to any sudden changes in their environment, such as people crossing the road or parked cars obstructing views.

Therefore, the correct answer reflects the established speed limit regulated by traffic laws in Illinois.