Thanks for your response.  I will try to clarify my point by quoting from your first comment in this thread: 

"Assuming future congestion cost will increase at the same rate and without rail by 2034, Honolulu’s congestion cost will be $734 million a year. In 2014 dollars Honolulu drivers will have wasted $13.5 billion during those twenty years. 

"Inflation and more cars on the road will increase the $13.5 billion exponentially and this does not include the loss in quality of life, urban sprawl taking over the North Shore and Windward Coast agriculture lands because the Oahu General Plan was scraped with the cancellation of rail." 

Whether these projections are your own or from the report you cited, this quote assumes "future congestion cost will increase at the same rate and without rail by 2034,"  That is clear.  But why should we assume "inflation and more cars" are givens, costs are certain to increase "exponentially", and ending rail will also end GP and increase urban sprawl?