In traffic forecasting for highways, the increase in traffic volume attributable to a general rise in the number of transport vehicles (independent of specific new projects) is termed what?

Introduction / Context:
Accurate traffic forecasting separates different components of future traffic so that design is neither overly conservative nor unsafe. Standard categories distinguish background growth from project-induced changes.

Given Data / Assumptions:

• Observed increase due to overall motorization and economic growth.
• No specific single development (like a new industrial estate) directly causing the rise.

Concept / Approach:
Normal traffic growth is the background increase tied to population, income, and vehicle ownership trends. Development traffic arises from a specific planned development in the influence area. Generated traffic is additional travel induced by improved facility/service level (e.g., new road reducing travel time). The question clearly points to background growth from more vehicles overall, hence “normal traffic growth.”

Step-by-Step Solution:
Identify growth driver: general rise in vehicle numbers.Map to category: normal (background) growth.Exclude other categories: not tied to a discrete development; not induced by the project itself.

Verification / Alternative check:
Highway planning texts and IRC guidance treat background growth separately so that generated/development traffic can be estimated and added explicitly when relevant.

Why Other Options Are Wrong:

• Development traffic: tied to specific land-use projects.
• Generated traffic growth: a consequence of improved facility or reduced impedance.
• Current traffic: a snapshot, not a growth category.

Common Pitfalls:

• Double counting growth by adding both normal and generated components without careful delineation.
• Using short-term seasonal spikes as trend indicators.

Final Answer:
Normal traffic growth