Trains are generally considered the most fuel-efficient mode of transportation because they can carry a large number of passengers or freight with relatively low energy consumption.

The Federal Aviation Administration (FAA) is responsible for regulating air traffic in the United States, ensuring the safety and efficiency of air travel.

Hill-start assist (HSA) is a safety feature that prevents vehicles from rolling backwards on a hill by automatically applying the brakes until the driver starts moving forward.

The maximum speed limit on most interstate highways in the United States is 75 mph, although some states may have lower or higher limits in certain areas.

A two-way street is a road that allows vehicles to travel in both directions.

The primary purpose of a traffic light is to control the flow of traffic at intersections and prevent collisions.

Seat belts are the primary safety feature designed to protect passengers in a vehicle in the event of a collision.

A yield sign at an intersection requires drivers to slow down and yield to oncoming traffic before proceeding.

Bicycles are generally considered the most environmentally friendly mode of transportation because they produce zero emissions and do not contribute to air pollution.

Roundabouts are designed to control the flow of traffic, reduce traffic congestion, and improve safety at intersections.

Anti-lock brakes (ABS), electronic stability control (ESC), and traction control system (TCS) are all safety features designed to prevent vehicles from skidding on slippery roads.

The purpose of a crosswalk at an intersection is to allow pedestrians to cross the street safely.

Airplanes are generally considered the fastest mode of transportation because they can travel at very high speeds.

The purpose of a stop sign at an intersection is to require drivers to stop completely before proceeding.

Lane keeping assist (LKA) is a safety feature that helps prevent vehicles from leaving their lane unintentionally by providing steering assistance.