Inventing millions of phantom trucks to sell a wider bridge
By Joe Cortright
The $7.5 billion plan to widen the I-5 bridges across the Columbia River is being sold, in part, based on claims that it will be used by millions of phantom trucks.
Metro’s biased truck modeling over-states current I-5 truck traffic by almost 70 percent: more than 2 million phantom trucks per year. Metro’s model says more than 17,000 trucks crossed the I-5 bridges each day in 2019; ODOT’s traffic data shows fewer than 10,000 truck crossings.
Truck traffic on the I-5 bridges is going down, and has declined almost half since 2005
Previous truck growth predictions for the CRC proved to be wildly wrong; the project’s EIS predicted truck traffic would grow more than 2 percent per year between 2005 and 2030; instead, it has declined at an annual rate of nearly 5 percent.
The decline isn’t an anomaly: statewide, Oregon truck freight volumes have declined 22 percent in the past 13 years, according to federal statistics
Metro’s truck traffic forecast isn’t based on a model: It just appropriates a growth factor based on an unrealistic and inaccurate federal data series that US Department of Transportation officials concede is used for political purposes, not actual decision-making.
In the ongoing debate surrounding the Interstate Bridge Replacement (IBR) project, a critical issue : the severe overestimation of truck traffic on the I-5 bridge. This commentary examines the flaws in current modeling practices and their potential impact on project planning and decision-making. IBR and Metro inflated truck counts to exaggerate the current importance of trucks, and built traffic models that grossly overestimate the growth in truck freight. In essence, these flawed traffic models mean that IBR is widening a freeway to accommodate that truck traffic that doesn’t now exist, and based on false predictions of future truck traffic growth–when in reality truck traffic has been declining.
Millions of phantom trucks are being used to justify a multi-billion dollar freeway widening
Metro’s forecast that grossly overstates current truck traffic
The most basic test of a model’s accuracy is whether its predictions match actually observed current reality. Metro’s traffic model—the basis for the IBR traffic estimates and environmental analysis—claims that 17,373 medium and large trucks (Class 4-13) crossed the I-5 bridge daily in 2019. We obtained the Metro traffic forecast information via a public records request. Here’s an excerpt of a spreadsheet showing estimated 2019 truck traffic crossing the I-5 bridges:
The figures for heavy and medium trucks in the northbound (nb) and southbound (sb) directions are highlighted. Together, these estimates total 17,373 trucks (6,861 + 6,813 + 1,853 + 1,845) daily.
Actual traffic data show’s that’s simply not true: Oregon Department of Transportation (ODOT) traffic count data (full data below) reports just 10,260 such trucks per day. This discrepancy amounts to a staggering overestimation of 69 percent – or 7,113 phantom trucks every day. Metro’s model simply isn’t accurate.
This isn’t a minor statistical error. It means planning for the I-5 bridges is somehow designed to accommodate more than than 2.6 million non-existent annual truck trips in the base year alone. The wild exaggeration of the scale of truck traffic shows that the Metro travel demand modeling is deeply flawed, and biased to support the sales pitch for bridge expansion. It’s hardly a reasonable basis for making a multi-billion dollar spending decision.
Historical trends vs. Metro predictions
Metro’s truck forecast doesn’t merely get current truck volumes wrong; it grossly misrepresents the historic trend. Metro claims truck traffic is up: Oregon Department of Transportation data show that truck traffic on the I-5 bridges has actually gone down. Here’s the data, downloaded from ODOT’s own website.
– In 2005, ODOT reported 19,428 class 5-13 trucks crossing the I-5 bridge daily.
– By 2019, this number had decreased to 9,809 trucks per day.
– This represents an annual decline of almost 5 percent annually over 14 years.
– Just prior to the pandemic, truck traffic on the I-5 bridges was down almost half compared to 2005
In spite of the historic trend in declining truck travel, the estimates developed by Metro and IBR make the startling claim that in the future, truck travel will increase dramatically. Metro predicts I-5 truck traffic will grow at 1.9 percent annually, projecting an increase from their (overestimated) 17,373 trucks in 2019 to 28,382 trucks in 2045 under the No Build scenario.
The Interstate Bridge Project has falsely portrayed truck traffic levels on the I-5 bridges as increasing. In public presentations, the IBR has claimed that truck traffic increased from 11,000 vehicles per day in 2005 to 14,000 vehicles per day in 2019. While that’s lower than the 17,373 trucks claimed in the Metro model, its still much higher than the number of trucks actually recorded by ODOT traffic counting.
IBR claims that I-5 bridge truck traffic rose by more than 25 percent between 2005 and 2019, when ODOT’s own traffic count data show that it declined by almost half over that same period.
Another forecast prepared by for IBR by Stantec, a so-called Level 2 traffic study, specifically called out the error in the Metro travel demand model’s truck estimates:
As shown before in Table 2-3, the heavy trucks constitute approximately 6.5% of total traffic on the I-5 Interstate Bridge. The [Metro] RTDM estimates heavy trucks to be about 9% of the total bridge traffic. As such, adjustments were necessary to reallocate the estimated truck trips to the proposed tolling classifications to be consistent with observed truck shares.
Stantec Level 2 Study, page 4-8
Stantec has a more realistic baseline—11,638 trucks per day in 2015—but calls for an even faster annual growth rate of 2.7 percent, to as many as 25,500 trucks in 2045.
A consistent pattern of exaggerating truck growth
Exaggerating the level and future growth of truck traffic is a long-standing tactic of the highway widening crowd. The Environmental Impact Statement for the proposed Columbia River Crossing (CRC) project—the IBR’s predecessor—using a previous version of Metro’s model, claimed that truck traffic would increase in a “No Build” scenario from 10,855 trucks per day in 2005 to 19,405 trucks per day in 2030 – an annual growth rate of 2.3 percent.
Reality has proven far different. Between 2005 and 2019, I-5 bridge truck traffic actually decreased at an annual rate of nearly 5 percent.
Freight forecasts have been proven wrong: Truck freight is declining, not increasing
Truck traffic levels are projected using a completely different “module” than the rest of the Metro regional travel demand model. The truck module is based on data which claims that truck traffic nationally (and locally) will increase steadily over time. The data source for this claim is highly suspect. Metro’s RTDM relies on the Federal Freight Analysis Framework 3 (FAF3), which is based on data from 2007 – now over 15 years out of date. Essentially, Metro just creates a “growth factor” from the FAF data and applies it to its (over-estimated) level of current truck traffic. Here’s an excerpt from Metro’s methodology explanation:
The FAF3 data essentially assumed steadily increasing tonnage flow of truck freight, and Metro essentially “copied and pasted” these growth factors into its model. But the continuous and aggressive growth assumed in FAF 3 hasn’t occurred. More recent versions of this data series (FAF4 and FAF5) show much lower levels of truck freight activity and project slower growth.
The 2011 Oregon Freight Plan, based on FAF2 data, projected an increase in truck freight from 294 million tons in 2010 to 508 million tons in 2035 – a 73% increase over 25 years (2.2% annual growth).
In reality, FAF5 data shows truck freight volumes declined from 294 million tons in 2010 to 229 million tons in 2023 – a decrease of 22% over 13 years (-1.9% annually).
In short, forecasts of future trucking activity in Oregon based on the Freight Analysis Framework have proven to be monumentally wrong: rather than increasing by more than 2 percent per year, statewide truck freight volumes have been declining at almost 2 percent per year. This updated FAF5 data—not mentioned in the Metro report or the DSEIS—confirm the pattern shown in ODOT traffic counts: truck traffic across the I-5 bridges is declining, not increasing. Yet the IBR is predicating on models that embrace outdated, and now completely discredited forecasts of ever-increasing truck volumes.
Freight Forecasts are a politically driven talking point, not real data
Not only that, but officials at the U.S. Department of Transportation concede that the truck forecasts in FAF are created for political purposes, and are not a valid basis for decision-making. The DOT’s chief economist wrote:
Other federal modal administrations prepare forecasts, but it is done more out of curiosity, to provide talking points for their administrators’ speeches. The Federal Highway Administration’s Office of Freight Operations has for the last several years prepared the Freight Analysis Framework, which forecasts freight flows out 20 years – not just for trucking, but for all modes of freight transportation. But we don’t actually use the FAF forecasts for any real decision-making. The forecasts help to inform the political process in a general way, and provide ammunition for politicians who want to spend more on transportation infrastructure.
The truck freight forecasts in the Freight Analysis Framework–especially the now out-dated FAF3 and FAF4 estimates aren’t a legitimate or sound basis for making transportation investments.
The Port Traffic Myth
Another misconception this analysis dispels is the oft-repeated claim that Port activity significantly impacts I-5 truck traffic. A 2013 study commissioned by ODOT found that only about 50 trucks per day from the Port of Portland’s Terminal 6 use the I-5 bridge. This amounts to roughly one truck every 30 minutes – hardly the flood of port-related traffic often cited to justify the project’s urgency.
The Port of Vancouver averages about 330 truck trips total per day, with no clear data on how many actually cross the I-5 bridge.
Bad Truck Estimates Undermine the IBR
The consequences of these overestimations extend far beyond academic interest. Accurate truck traffic forecasts are crucial for several reasons:
1. Project Justification: Inflated truck traffic numbers may be used to overstate the need for capacity expansion.
2. Design Considerations: Overestimating truck volumes could lead to overbuilt infrastructure, wasting taxpayer money.
3. Toll Revenue Projections: Truck tolls are four times higher than those charged to cars, so getting the estimate to truck traffic right is essential to any financial analysis. As noted by transportation expert Robert Bain, unreliable truck forecasts can significantly impact projected toll revenues, potentially putting the financial viability of the project at risk.
The Need for Accountability and Transparency
Given the magnitude of the discrepancies identified, it’s crucial that Metro and other agencies involved in the IBR project address these issues openly. Oregon and Washington officials should:
1. Commission a thorough, independent review of the truck traffic modeling methodologies being used.
2. Understand why the models diverge so significantly from ODOT’s actual traffic count data.
3. Update forecasts using the most recent FAF5 data, with a critical examination of its applicability to real-world decision-making.
4. Right-size the project’s design in light of more accurate truck traffic data.
Conclusion
The phantom trucks populating Metro’s models represent more than just a statistical anomaly. They embody a broader pattern of biased forecasting that has plagued major infrastructure projects for decades. As we contemplate spending billions on the Interstate Bridge Replacement, it’s imperative that we base our decisions on robust, reality-based data rather than inflated projections.
To summarize the key statistical discrepancies:
– Current traffic: Metro claims 17,373 trucks/day vs. ODOT’s 10,260 trucks/day (69% overestimation)
– Historical trend: 4-5% annual decline (2005-2019) vs. Metro’s projected 1.9% annual growth
– Long-term forecast: Metro projects 28,382 trucks/day by 2045, while the historical trend would suggest fewer than 7,000 trucks/day if continued
The citizens of Portland and Vancouver deserve infrastructure planning grounded in fact, not fiction. It’s time to exorcise these phantom trucks from our models and engage in a clear-eyed, data-driven discussion about the true needs of our regional transportation system.
ODOT’s I-5 Traffic Count Data, by Vehicle Class, 2005-2019
Inventing millions of phantom trucks to sell a wider bridge
The $7.5 billion plan to widen the I-5 bridges across the Columbia River is being sold, in part, based on claims that it will be used by millions of phantom trucks.
Metro’s biased truck modeling over-states current I-5 truck traffic by almost 70 percent: more than 2 million phantom trucks per year. Metro’s model says more than 17,000 trucks crossed the I-5 bridges each day in 2019; ODOT’s traffic data shows fewer than 10,000 truck crossings.
Truck traffic on the I-5 bridges is going down, and has declined almost half since 2005
Previous truck growth predictions for the CRC proved to be wildly wrong; the project’s EIS predicted truck traffic would grow more than 2 percent per year between 2005 and 2030; instead, it has declined at an annual rate of nearly 5 percent.
The decline isn’t an anomaly: statewide, Oregon truck freight volumes have declined 22 percent in the past 13 years, according to federal statistics
Metro’s truck traffic forecast isn’t based on a model: It just appropriates a growth factor based on an unrealistic and inaccurate federal data series that US Department of Transportation officials concede is used for political purposes, not actual decision-making.
In the ongoing debate surrounding the Interstate Bridge Replacement (IBR) project, a critical issue : the severe overestimation of truck traffic on the I-5 bridge. This commentary examines the flaws in current modeling practices and their potential impact on project planning and decision-making. IBR and Metro inflated truck counts to exaggerate the current importance of trucks, and built traffic models that grossly overestimate the growth in truck freight. In essence, these flawed traffic models mean that IBR is widening a freeway to accommodate that truck traffic that doesn’t now exist, and based on false predictions of future truck traffic growth–when in reality truck traffic has been declining.
Metro’s forecast that grossly overstates current truck traffic
The most basic test of a model’s accuracy is whether its predictions match actually observed current reality. Metro’s traffic model—the basis for the IBR traffic estimates and environmental analysis—claims that 17,373 medium and large trucks (Class 4-13) crossed the I-5 bridge daily in 2019. We obtained the Metro traffic forecast information via a public records request. Here’s an excerpt of a spreadsheet showing estimated 2019 truck traffic crossing the I-5 bridges:
The figures for heavy and medium trucks in the northbound (nb) and southbound (sb) directions are highlighted. Together, these estimates total 17,373 trucks (6,861 + 6,813 + 1,853 + 1,845) daily.
Actual traffic data show’s that’s simply not true: Oregon Department of Transportation (ODOT) traffic count data (full data below) reports just 10,260 such trucks per day. This discrepancy amounts to a staggering overestimation of 69 percent – or 7,113 phantom trucks every day. Metro’s model simply isn’t accurate.
This isn’t a minor statistical error. It means planning for the I-5 bridges is somehow designed to accommodate more than than 2.6 million non-existent annual truck trips in the base year alone. The wild exaggeration of the scale of truck traffic shows that the Metro travel demand modeling is deeply flawed, and biased to support the sales pitch for bridge expansion. It’s hardly a reasonable basis for making a multi-billion dollar spending decision.
Historical trends vs. Metro predictions
Metro’s truck forecast doesn’t merely get current truck volumes wrong; it grossly misrepresents the historic trend. Metro claims truck traffic is up: Oregon Department of Transportation data show that truck traffic on the I-5 bridges has actually gone down. Here’s the data, downloaded from ODOT’s own website.
– In 2005, ODOT reported 19,428 class 5-13 trucks crossing the I-5 bridge daily.
– By 2019, this number had decreased to 9,809 trucks per day.
– This represents an annual decline of almost 5 percent annually over 14 years.
– Just prior to the pandemic, truck traffic on the I-5 bridges was down almost half compared to 2005
In spite of the historic trend in declining truck travel, the estimates developed by Metro and IBR make the startling claim that in the future, truck travel will increase dramatically. Metro predicts I-5 truck traffic will grow at 1.9 percent annually, projecting an increase from their (overestimated) 17,373 trucks in 2019 to 28,382 trucks in 2045 under the No Build scenario.
The Interstate Bridge Project has falsely portrayed truck traffic levels on the I-5 bridges as increasing. In public presentations, the IBR has claimed that truck traffic increased from 11,000 vehicles per day in 2005 to 14,000 vehicles per day in 2019. While that’s lower than the 17,373 trucks claimed in the Metro model, its still much higher than the number of trucks actually recorded by ODOT traffic counting.
IBR claims that I-5 bridge truck traffic rose by more than 25 percent between 2005 and 2019, when ODOT’s own traffic count data show that it declined by almost half over that same period.
Another forecast prepared by for IBR by Stantec, a so-called Level 2 traffic study, specifically called out the error in the Metro travel demand model’s truck estimates:
Stantec has a more realistic baseline—11,638 trucks per day in 2015—but calls for an even faster annual growth rate of 2.7 percent, to as many as 25,500 trucks in 2045.
A consistent pattern of exaggerating truck growth
Exaggerating the level and future growth of truck traffic is a long-standing tactic of the highway widening crowd. The Environmental Impact Statement for the proposed Columbia River Crossing (CRC) project—the IBR’s predecessor—using a previous version of Metro’s model, claimed that truck traffic would increase in a “No Build” scenario from 10,855 trucks per day in 2005 to 19,405 trucks per day in 2030 – an annual growth rate of 2.3 percent.
Reality has proven far different. Between 2005 and 2019, I-5 bridge truck traffic actually decreased at an annual rate of nearly 5 percent.
Freight forecasts have been proven wrong: Truck freight is declining, not increasing
Truck traffic levels are projected using a completely different “module” than the rest of the Metro regional travel demand model. The truck module is based on data which claims that truck traffic nationally (and locally) will increase steadily over time. The data source for this claim is highly suspect. Metro’s RTDM relies on the Federal Freight Analysis Framework 3 (FAF3), which is based on data from 2007 – now over 15 years out of date. Essentially, Metro just creates a “growth factor” from the FAF data and applies it to its (over-estimated) level of current truck traffic. Here’s an excerpt from Metro’s methodology explanation:
The FAF3 data essentially assumed steadily increasing tonnage flow of truck freight, and Metro essentially “copied and pasted” these growth factors into its model. But the continuous and aggressive growth assumed in FAF 3 hasn’t occurred. More recent versions of this data series (FAF4 and FAF5) show much lower levels of truck freight activity and project slower growth.
In short, forecasts of future trucking activity in Oregon based on the Freight Analysis Framework have proven to be monumentally wrong: rather than increasing by more than 2 percent per year, statewide truck freight volumes have been declining at almost 2 percent per year. This updated FAF5 data—not mentioned in the Metro report or the DSEIS—confirm the pattern shown in ODOT traffic counts: truck traffic across the I-5 bridges is declining, not increasing. Yet the IBR is predicating on models that embrace outdated, and now completely discredited forecasts of ever-increasing truck volumes.
Freight Forecasts are a politically driven talking point, not real data
Not only that, but officials at the U.S. Department of Transportation concede that the truck forecasts in FAF are created for political purposes, and are not a valid basis for decision-making. The DOT’s chief economist wrote:
The truck freight forecasts in the Freight Analysis Framework–especially the now out-dated FAF3 and FAF4 estimates aren’t a legitimate or sound basis for making transportation investments.
The Port Traffic Myth
Another misconception this analysis dispels is the oft-repeated claim that Port activity significantly impacts I-5 truck traffic. A 2013 study commissioned by ODOT found that only about 50 trucks per day from the Port of Portland’s Terminal 6 use the I-5 bridge. This amounts to roughly one truck every 30 minutes – hardly the flood of port-related traffic often cited to justify the project’s urgency.
The Port of Vancouver averages about 330 truck trips total per day, with no clear data on how many actually cross the I-5 bridge.
Bad Truck Estimates Undermine the IBR
The consequences of these overestimations extend far beyond academic interest. Accurate truck traffic forecasts are crucial for several reasons:
1. Project Justification: Inflated truck traffic numbers may be used to overstate the need for capacity expansion.
2. Design Considerations: Overestimating truck volumes could lead to overbuilt infrastructure, wasting taxpayer money.
3. Toll Revenue Projections: Truck tolls are four times higher than those charged to cars, so getting the estimate to truck traffic right is essential to any financial analysis. As noted by transportation expert Robert Bain, unreliable truck forecasts can significantly impact projected toll revenues, potentially putting the financial viability of the project at risk.
The Need for Accountability and Transparency
Given the magnitude of the discrepancies identified, it’s crucial that Metro and other agencies involved in the IBR project address these issues openly. Oregon and Washington officials should:
1. Commission a thorough, independent review of the truck traffic modeling methodologies being used.
2. Understand why the models diverge so significantly from ODOT’s actual traffic count data.
3. Update forecasts using the most recent FAF5 data, with a critical examination of its applicability to real-world decision-making.
4. Right-size the project’s design in light of more accurate truck traffic data.
Conclusion
The phantom trucks populating Metro’s models represent more than just a statistical anomaly. They embody a broader pattern of biased forecasting that has plagued major infrastructure projects for decades. As we contemplate spending billions on the Interstate Bridge Replacement, it’s imperative that we base our decisions on robust, reality-based data rather than inflated projections.
To summarize the key statistical discrepancies:
– Current traffic: Metro claims 17,373 trucks/day vs. ODOT’s 10,260 trucks/day (69% overestimation)
– Historical trend: 4-5% annual decline (2005-2019) vs. Metro’s projected 1.9% annual growth
– Long-term forecast: Metro projects 28,382 trucks/day by 2045, while the historical trend would suggest fewer than 7,000 trucks/day if continued
The citizens of Portland and Vancouver deserve infrastructure planning grounded in fact, not fiction. It’s time to exorcise these phantom trucks from our models and engage in a clear-eyed, data-driven discussion about the true needs of our regional transportation system.
ODOT’s I-5 Traffic Count Data, by Vehicle Class, 2005-2019
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