Despite significant investments in transit and bike systems, the overall number of trips taken in automobiles in the Portland metro area has barely decreased in the past two decades, according to a new transportation study.

Whether it's the daily work commute or a quick dash to the supermarket, people choose to drive about 84 percent of the time, the Metro household survey shows. That's a downward shift of just 3.6 percent since 1994, the last time the regional government conducted a comprehensive survey of household travel patterns.

Still, when it comes to just "commuting trips" between work and home -- about 25 percent of all travel in the region -- the percentage of people who choose to take public transit, bike or walk has nearly doubled during that period,

Eighteen years ago, 90 percent of commuters drove or took carpools to their jobs. Today, it's about 81 percent, indicating that nearly one in five workers now forgo the daily grind of traffic jams and paying for parking.

During a presentation of the research Tuesday, Metro board members asked the authors of the $1 million study to dig even deeper to find data showing the agency's land-use planning is paying dividends.

Despite only a modest decline in overall auto use in a region known for flexing its bicycle and public-transit muscle, Metro Councilor Rex Burkholder said, "there is an incredible story here."

Certainly, the portrait of Portland area travelers contains signs of progress on so-called "active transportation" planning that aims to get people out of their cars.

Based on demographically weighted estimates from the survey of 6,450 households in Multnomah, Washington, Clackamas and Clark Counties, the share of workers commuting by TriMet and C-Tran has nearly doubled to 11 percent in the past 18 years.

What's more, nearly 45 percent of all commuter trips into Portland's "central business district" – encompassing the area within downtown's interstate loop – are on public transit, the data show.

In 1994, it was about 37 percent.

However, in the Oregon suburbs, the transit-ridership numbers aren't as impressive, with only 4.2 percent of residents choosing TriMet compared to 2 percent in the last study. Clark County's residents have an even smaller transit mode share: 1.4 percent.

Metro planners have long operated on the assumption that people don't want to spend time in their cars. The elected regional government has championed sustainable growth policies, which has included investing millions of dollars in light-rail construction and bike projects.

Any shift away from the automobile, they contend, is a sign that the agency's goals to improve the region's environment and health are succeeding.

But the new study does not appear to factor in the effects of the Great Recession and skyrocketing gas prices in recent years.

Glenn Howell of Forest Grove, a security guard who switched to a two-hour daily TriMet commute to his job at Kaiser Permanente on North Interstate Avenue, said he would rather drive.

"My car gets me to and from work faster," Howell said. "Faster means more family time. But $5 a day for TriMet beats $8 for two gallons of gas."

Although the automobile is still king, the survey provides plenty of evidence that residents are spending less time behind the wheel than they were in 1994:

An average Portland area household makes an estimated 9.9 trips per day, which is comparable to 1994, the study showed. The higher the income and the greater the number of children, the more trips a household makes, according to the findings.

When Portland area residents drive, the they aren't driving as far. The average number of miles put on a driver's odometer has declined about 10 percent to 17.1 a day. That's a long way from the national average of 22.5 vehicle miles traveled.

Meanwhile, the average length of each trip, which could be everything from a child's soccer practice to a barbecue at a friend's house, has declined from 5.1 miles to 4.4 miles.

Bicyclists make up about 4 percent of daily commuters and nearly 3 percent of all trips, the survey shows. In 1994, only 1 percent of those trips were taken by bike.

The bicycle travel numbers are the only segment of the survey showing a notable deviation from the

, which showed just over 2 percent of the region's residents commute by bike.

The disparity, said Mike Hoglund, director of Metro's research center, is probably due to differences in how each survey's questions were asked.

The U.S. Census survey asks respondents to list their primary mode of commuting. The Metro study, which was conducted in 2009 in Clark County and 2011 in the region's other counties, asked households to keep a one-day journal of how they got around.

Nearly 29 percent of households said they owned a bicycle. Not surprisingly, the survey found that people in denser neighborhoods with dedicated bike boulevards and other infrastructure are more likely to pedal to their destinations.

About 13 percent of central city residents -- a big jump from 3 percent in 1994 -- listed it as their mode of travel versus 1.5 percent in the Oregon suburbs.

Hoglund and co-author Richard Walker said the findings provide "core transportation information to make a great place."

However, a demographic breakdown of automobile users was conspicuously missing from the information presented to the Metro board.

The only thing remotely close was a dissection of those who use the Columbia River bridges. About 18 percent of Clark County households traveled to Oregon on the survey day, while only 2 percent of Multnomah, Washington and Clackamas residents went north.

Councilor Shirley Craddick was among those who asked for greater information comparing traveling patterns between inner-city residents and those in the suburbs.

"It might help use influence and get some support in that outer rim," Craddick said.

-- Joseph Rose

