IBR Traffic Forecasts Violate Portland Region’s Climate Commitments. Portland’s adopted Regional Transportation Plan commits the Metro area to reduce total vehicle miles traveled by 12 percent over the next twenty-five years. But the traffic forecasts used to justify the $7.5 billion Interstate Bridge Replacement (IBR) Project call for more than a 25 percent increase in driving over that same time period.
The RTP is required under state law to plan for a reduction in VMT per capita; the RTP is the way that regional and local governments show they comply with these state climate requirements. But the IBR planning is predicated on a world where we drive much more and not any less.