Scientific planning of transportation system and mass transit facilities in cities should be based on A. spot speed data B. origin and destination data C. traffic volume data D. accident data

The correct answer is: B. origin and destination data.

Origin and destination data is the most important data for scientific planning of transportation system and mass transit facilities in cities. It provides information on where people are coming from and going to, which can be used to determine the best locations for transportation facilities.

Spot speed data is the speed of vehicles at a particular location at a particular time. It can be used to identify areas of congestion, but it does not provide information on where people are going.

Traffic volume data is the number of vehicles that pass a particular location in a given period of time. It can be used to estimate the demand for transportation, but it does not provide information on where people are going.

Accident data is information on the number and severity of accidents that occur at a particular location. It can be used to identify areas of safety concern, but it does not provide information on where people are going.

In conclusion, origin and destination data is the most important data for scientific planning of transportation system and mass transit facilities in cities. It provides information on where people are coming from and going to, which can be used to determine the best locations for transportation facilities.