Category «Travel Modeling»

Greenhouse Gas Emissions Reductions from Traffic Improvements Are at Best Negligible 4th Order Effects

Checking some citations within a draft report that I have been reading led me to pervasive alternative facts about the relationship between greenhouse gas emissions and traffic improvement strategies.  It seems that not only are we daily subjected to incorrect interpretations about the sources of global warming, but we are additionally subjected to incorrect ideas …

Musings on Scenario Development for Travel Forecasting

Truth be told, I volunteered to be a Foresight Ambassador for NCHRP. My and the several other ambassadors’ mission was to spread the word about NCHRP Foresight Reports 750. This series of six reports, as you have probably heard, develops future scenarios for transportation development and planning. All rookie ambassadors were supplied with a one-day …

How Does a Traffic Signal Become a Traffic Signal?

After a recent presentation to the North Carolina Model Users Group about node delays in travel forecasting networks, I was asked how one knows where traffic signals should be on future-year networks. This is a complicated question, and my answer was sketchy and not particularly satisfying. I alluded to two papers I wrote on the …

My Life with MSA*

QRS II had always had a form of feedback to trip distribution (more correctly to trip generation, although the trip generation step was insensitive to network travel times). In 1988 or so when I was testing a new installation of a “modified” Evans’ algorithm I had put into QRS II, which was quite similar to …