A draft report from the Oregon Department of Transportation says a strategic freeway bottleneck mitigation project cut traffic delays by 10 percent, saving greater Portland commuters countless hours they'd otherwise spend sitting in traffic.
The Interstate 84 widening project, which added a half mile-long lane on eastbound I-84 in the Gateway District, improved afternoon rush hour travel times and speeds by 5 percent, and improved the freeway's reliability by 43 percent.
The report is being developed as state and regional leaders look into incorporating more strategic bottleneck relief projects into a proposal to modernize Oregon's transportation funding system.
In 2012, ODOT had a common-sense idea: Improve the efficiency of road construction, by using cost savings elsewhere to enhance an already-planned project.
With a repaving project on I-84 in Portland set to begin, ODOT asked the Metro Council for permission to spend another $6 million to add the half-mile lane in the Gateway District. The project needed Metro's approval because it wasn't already in the Regional Transportation Plan.
The project, at the time, was hailed as a way to strategically address the region's traffic bottlenecks.
"This is a very short piece of expansion and it can really have an impact on helping reduce congestion," said Metro Councilor Shirley Craddick in 2012. "That is a major roadblock – literally – for I-84 all the way from I-5 to that interchange."
The new analysis from ODOT shows that improving the system by investing in smart projects works.
In 2013, before the project on I-84, eastbound commuters had to plan for 12 minutes of "buffer time" in their commute – basically, how early they'd have to leave to be sure they made it to their destination on time, even if traffic was bad.
After the strategic investment, the buffer time on eastbound I-84 dropped to 6.8 minutes – a 43 percent decrease.
The draft report from ODOT, which is expected to be released later this spring, outlines how the buffer time increased from 2013 to 2015 as greater Portland's population increased and economy boomed.
On the Interstate 5 corridor, southbound buffer times went up 35 percent, to 46 minutes, highest in the region. On Interstate 205, northbound buffer times went up 39 percent, to 43 minutes.
Since the widening project on I-84, greater Portland has opened 7 miles of new light rail, and invested $40 million in federal money into active transportation projects.
At the same time, MAX trains have also seen increases in ridership. From October 2013 to October 2015, MAX gained nearly 50,000 weekly riders; in 2014, MAX carried 30,429 commuters daily through the Lloyd District, compared to 144,885 cars on the adjacent freeway – about 17 percent of traffic.
“There are obvious bottlenecks that have become apparent over time that need to be addressed," said Metro Councilor Craig Dirksen. "A recent example is the improvement to I-84 at its intersection with I-205 in the Gateway area. Three others have been identified by ODOT and have universal support in the region: I-5 at the Rose Quarter, I-205 in Clackamas County including the Abernathy Bridge over the Willamette River, and Highway 217 between Tigard and Beaverton. These improvements need to be part of a multi-modal improvement package that will create the complete transportation system we need for the decades ahead.”
The report highlighted how other innovative congestion investments can improve traffic. On Highway 217 in Washington County, afternoon travel times have decreased.
"This is the result of the ATM (advanced traffic management) project that was deployed in 2014," the report said. "In corridors with no improvements, degradation in average and buffer travel time is seen across all hours of the day, whereas for OR 217, the PM has improved."
Regional leaders are calling for further strategic investments to reduce congestion in greater Portland. Those include reconfiguring the 60-year-old design of the Rose Quarter interchange; widening Interstate 205 from two to three lanes in Clackamas County, where traffic has more than doubled since 1985; and improving Highway 217 in Tigard, which is still two lanes in each direction despite carrying more than 100,000 cars a day.