Final answer:
The correct answer is option 2) 1948, indicating that turn signals were mandated for all motor vehicles manufactured after this model year, enhancing road safety.
Step-by-step explanation:
The correct answer is option 2) 1948. Turn signal indicators, also known as turn signals or blinkers, are a critical safety feature on motor vehicles. They provide a clear indication to other drivers and pedestrians about a vehicle's intended direction of travel. The use of turn signals helps prevent accidents by allowing a vehicle to communicate its intention to turn or change lanes. According to the United States regulations, turn signal indicators have been a mandate on all motor vehicles manufactured after the model year 1948. The presence of turn signals is especially important at intersections, where the need to clearly communicate intentions can prevent misunderstandings on the road that could lead to accidents. Road safety is significantly improved with the implementation of such features.
Turn signal indicators were required on all motor vehicles manufactured after the model year 1971. This requirement was put in place to improve road safety and reduce the number of accidents at intersections. Prior to 1971, some vehicles may have had turn signals as optional equipment, but they were not mandatory.