Is Travel Modeling Science or Engineering?
Merriam Webster defines science and engineering as follows:
Knowledge about or study of the natural world based on facts learned through experiments and observation.
[A] The application of science and mathematics by which the properties of matter and the sources of energy in nature are made useful to people.
[B] The design and manufacture of complex products.
It could be argued that various aspects of travel modeling exists as either a science or engineering discipline as follows:
Science
Aspects of travel modeling that are directly observable and can be empirically tested to support a theory
- travel behavior research including psychology, sociology, and behavioral economics
- traffic flow theory, car following behavior
- network analysis
- etc.
Engineering
Aspects of travel modeling that synthesize the science and mathematics into something useful to people include:
- ridership forecasting
- project level forecasting
- discrete choice model estimation results
- long-range forecasting
- toll-road forecasting
- etc.
What has been historically been described as "travel model development" fits in with Webster's second definition of Engineering, as the design and manufacture of complex products:
- discrete choice modeling
- agent-based modeling
- activity-based travel models
- aggregate, four-step travel models
- dynamic traffic assignment
- static traffic assignment
- etc.
From Science to Engineering
Travel forecasting practice lacks a rigorous approach to (A) prioritizing advances in science that will result in more usefulness to people as well as (B) synthesizing these advances into engineering practice.