In an expressway with 4 lanes in one direction, what type of vehicles are allowed in the outermost right lane?

The outermost right lane of a four-lane expressway is typically designated for specific types of vehicles, which often include special and construction equipment vehicles. This lane usually serves purposes related to safety and traffic flow, making it suitable for vehicles that might not adhere to the standard speed limits or that require additional space due to their size and operational requirements.

Special and construction vehicles often have unique speed restrictions and may need to navigate in ways that differ from typical passenger cars and motorcycles. By allowing these vehicles in the outermost lane, it reduces the risk of accidents that could occur if they were required to travel at higher speeds alongside faster-moving traffic.

Motorcycles, while inherently considered smaller vehicles, have their own designated lanes in many jurisdictions and often do not need to be restricted to the outermost lane. Meanwhile, passenger cars traveling at a specific speed, such as 80 km/h, would generally be expected to use the middle lanes where faster or typical vehicles are traveling. Hence, the outermost lane is not the preferred location for these vehicles because it is meant for those that can operate differently or be more dangerous when mixed with regular traffic.