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Source: The Oregonian (Portland)
Author: Lisa Grace Lednicer
(Oregon) Commuters' nightmare
Original Article

PORTLAND – On a chilly morning last December, 17 minutes before the start of rush hour, the murmur of a crisis flashed across Ron Kroop's pager.
The district manager for the Oregon Department of Transportation hopped into his truck and threaded past a conga line of cars before stopping in the Terwilliger Curves, one of the region's most accident-prone stretches of highway. In front of him on Interstate 5 lay a jackknifed tractor-trailer, splayed across two lanes of traffic.
The truck driver -- traveling about 65 mph, according to an investigator -- unwittingly had demonstrated that normal freeway speed is too fast for this curvy stretch of I-5, which now carries five times the traffic as when it opened in 1961.
Even though highway workers did what they could to divert drivers, the relatively minor accident locked up the region's freeways for 31/2 hours and caused delays up to 20 miles away.
It's a scenario likely to play out again and again as commuters stubbornly ignore the 50 mph speed limit and traffic continues to mount between Portland and some of its rapidly growing suburbs.
While Washington has the Beltway and New York has the Long Island Expressway, in Portland it's hard to beat the Terwilliger Curves for sheer rush-hour vexation. Squeezed between bluffs and a river, the highway twists and turns through an area with few alternative routes, making it a flash point for crashes, congestion and commuter frustration.
Transportation officials say there is a way to significantly reduce the number of accidents on the curves: strictly enforce the 50 mph speed limit as cars negotiate their way through the 7-degree bends. But that would further snarl the daily commute for the 129,400 drivers funneling through each day.
Officials note that while the accident rate is above the state average, few people die on the curves. The number of accidents is declining because of safety improvements that include repaving and upgrading the median between north and southbound lanes.
No one is pushing for a change in the speed limit, even though the impact of a big accident on the daily commute grows more severe each year. Officials say the occasional three-hour backup is a reasonable price to pay to keep the cars flowing most mornings.
"We're always going to have crashes," says KC Humphrey, transportation safety advocate for ODOT's Region 1 division in Portland. "At some point we say, 'What can we live with?' "
Demonstration of physics 
For those who drive the 1.7-mile stretch of I-5 between Spring Garden and Iowa streets, the Terwilliger Curves pose challenges unique to freeways in the state.
Five times in just over a mile, the curves change from gentle to sharp. The result for a driver comes down to a physics lesson: It's harder to keep a vehicle in one lane when going around a curve than when traveling a straight stretch of road. The tighter the curve and the higher the speed, the harder it is to keep the car in the same path.
Driving even 5 mph over the speed limit increases the difficulty of going around a curve by about 20 percent. The boatlike cars popular when the road was built had an easier time negotiating the road; today's SUVs and tractor-trailer rigs, already prone to tipping with their higher centers of gravity, are especially vulnerable as they speed around curves.
Additionally, the sharpness, or radius, changes near entrances and exits to the freeway. Drivers get pulled to the right and left as they attempt to dodge merging cars. Navigating all that gets especially dicey for distracted commuters punching numbers into a cell phone, thumbing their BlackBerrys and sipping coffee.
Transportation workers have posted caution signs as well as 50 mph speed limit signs along the curves. But commuters, accustomed to gliding to work along the straight stretches of I-5 to the north and south at 60 mph, tend to ignore them. As the number of cars per lane has increased, the number of rear-enders has gone up, too, as compacts jostle with tractor-trailers for space.
"Nobody could have imagined in 1960 that the curves would carry the traffic volumes of today," said Brian Ray, an engineer with Kittelson & Associates, a local transportation consulting firm. "The volumes uncovered a multitude of sins."
Competition and pressure 
The road that would become a source of frustration for today's commuters was met with little discussion or controversy when it was proposed as the final segment of I-5 in the early 1950s, a time when states competed with each other to see who could finish their interstates first.
Influential state Highway Engineer R.H. "Sam" Baldock, who led the construction of the interstate system in Oregon, urged a state panel in 1952 to approve the twisty course, even though it ran counter to the federal ideal of a straight road. Pressure to relieve overcrowding on nearby Southwest Barbur Boulevard was intense, and Baldock told panel members that if they didn't act quickly, developers would snap up chunks of the planned route for pricey houses. Besides, he added, there simply wasn't a better option.
None of the committee members objected. Portland city commissioners, given the chance to hold public hearings on the proposal, declined. At the ribbon-cutting in December 1961, elected officials bragged that Oregon now had the longest stretch of freeway in the country.
But the curves have bedeviled engineers and commuters since the first decade of their opening. By 1970, highway engineers were reporting that the accident rate near Terwilliger Boulevard was more than 50 percent higher than the statewide average, making it one of the five worst sections in Oregon for freeway accidents.
In response, engineers installed concrete dividers and lengthened the entrance ramps. Later they built guardrails, reinforced barriers and installed rumble strips to jolt drivers awake. In 1992, they re-built the Terwilliger Boulevard interchange to ease traffic flow problems.
Three years later, officials lowered the speed limit from 55 mph to 50 mph. Police intensified patrols and wrote more than 1,000 tickets in just two months.
The effect was dramatic: In the month before the change, police received 45 calls for accident assistance. In the first full month afterward, the number fell to 12. The trend continued for six months, but when police backed off the patrols, the calls for accident assistance crept back up.
Portland Police Officer Tom Larson, nicknamed "Terwilliger Tom" because he regularly patrols the area, said increased ticketing would shrink the number of crashes but it's not a perfect solution.
"No matter how hard you enforce the limit," he said, "there's always gonna be a numbskull coming by and screwing it up."
Persistently high crash rate 
The fixes have helped somewhat. ODOT statistics over the past decade show the number of accidents has decreased, as has the crash rate -- a measurement of the number of crashes per million miles traveled.
Yet the problems persist. For 15 of the past 19 years, statistics show, the curves' crash rate has remained higher than the statewide average. And although the crash rate on the curves has been falling, it has been falling more slowly than the statewide rate.
With an average of 100 crashes per year in the curves over the past decade, the stretch is one of the most frequent accident locations on I-5 in Oregon, according to federal officials. One senior federal official said Oregon should study whether the road needs redesigning.
"I don't think they're looking at the cumulative effects of safety and congestion," said David Cox, division administrator for the Oregon office of the Federal Highway Administration.
The cost of an accident goes beyond injuries and crumpled fenders, Cox said. With alternative routes either overcrowded or hard to reach, ambulance drivers, delivery people and commuters all lose valuable time when trapped in an accident-induced jam.
"If an accident happens," Cox said, "there's not a lot of opportunities to back out and go a different way."
Realignment would be disruptive 
If state highway engineers were building the road today, they said, they'd straighten the curves to allow commuters to drive through the section at the normal freeway speed of 60 mph.
A blueprint sketched by an ODOT engineer 16 years ago shows gentler curves near the Terwilliger Boulevard and Brier Place interchanges, where most of the accidents over the past five years have occurred. Engineers who re-built the Terwilliger Boulevard overpass positioned the columns far enough from the curves to allow for an eventual realignment.
But just because a plan is technically feasible doesn't make it politically doable. Even a minor adjustment to the curves, transportation officials say, would cut a swath across Southwest Portland, chopping into Fulton Park and demolishing homes on Canby Street. It would cost upward of $100 million -- roughly what it took to film the movie "The Aviator."
So instead, highway officials continue to nibble around the edges. Last year, they began a $23 million safety improvement project scheduled to end this spring. Workers will install new flashing yellow warning lights at the north end of the curves, repave the highway, add reflective road striping and refurbish nine concrete slabs where police can park their cars and aim their radar guns.
There are no plans for extensive work on the curves over the next 20 years. Officials said it's not necessary, noting that there have been only two deaths on the road in the past 18 years. More congested roads such as Sunset Highway deserve more money, they said.
"Compared to other highways in the state, that's not a horrific section," said Robin McArthur, manager for planning and development for ODOT's Portland region. "We've seen success with what we're doing on that segment of highway, and we hope we'll see the crashes go down."