Question

1. Explain why principal arterials carry 50% of the traffic volume but only 5% of the highway system mileage.

Answer 1

Arterial roads are the roads that connect the minor streets in the cities to one another and also to the inter city expressways and freeways. Because of this, arterial roads have to bear a brunt of a heavy traffic coming from the minor streets. Even thought heavy traffic is adjusted for by expanding the arterial roads, the improvement is not sufficient to manage the rte of increase of traffic.

Especially during peak hours, many vehicles pour into the arterial roads making it even difficult. Apart from this, these roads have intersections which are usually signaled and this signalling piles up the traffic even faster.

This results in the atrerial roads being piled up with heavy traffic.

The main reasons can be summarised as:

1-Due to less capacity than the combined capacity of the collector roads that inflow into the arterial road.

2-Due to lifestyle causes, rush hour related traffic.

3-Due to frequent intersections and signalling.