The correct answer is: B. Traffic capacity should always be more than traffic volume.
Traffic volume is the number of vehicles that pass a point on a road during a given time period. Traffic capacity is the maximum number of vehicles that can safely pass a point on a road during a given time period.
If traffic volume is greater than traffic capacity, then the road will become congested, and traffic will slow down. This can lead to delays, accidents, and air pollution.
Therefore, it is important to ensure that traffic capacity is always greater than traffic volume. This can be done by widening roads, adding lanes, or improving traffic signals.
Option A is incorrect because traffic volume should never be more than traffic capacity. If traffic volume is more than traffic capacity, then the road will become congested, and traffic will slow down. This can lead to delays, accidents, and air pollution.
Option C is incorrect because spot speed is the average speed of a vehicle at a specified section, not the total number of vehicles that pass a point on a road during a given time period.
Option D is incorrect because the 85th percentile speed is the speed at which 85% of the vehicles on a road are traveling or less, while the 98th percentile speed is the speed at which 98% of the vehicles on a road are traveling or less. Therefore, the 85th percentile speed is always less than the 98th percentile speed.