The Barton Creek bike bridges project, a decade in the making and an unprecedented commitment to cycling in Austin, will open in stages between now and the end of the year.
The northern end of the project, which includes surface trails on each side of Loop 360 at South MoPac Boulevard and two short bridges over Loop 360, could open informally within a week after workers put up temporary chain-link fences for safety, said Chad Crager, the city of Austin’s division manager over urban trails. By October, after permanent railings are in place, that $3 million northern piece will be fully open.
Then, by the end of December if the schedule holds, the 1,100-foot-long concrete bridge over the gorge of Barton Creek, a 14-foot-wide structure that looms 70 feet above the water, should be done. Workers with Austin Bridge and Road Co. were working Friday on the last of eight bridge spans, and work remains to be done on land at both ends where the bridge connects.
And there’s good news here for drivers: Once the main bike bridge is open and southbound cyclists no longer have to use the shoulder of MoPac, the Texas Department of Transportation will restripe that section of the highway to have three vehicle lanes continuously southbound rather than the current two.
That south part of the project (including the highway work) will cost $8.9 million, with the cost split roughly equally between TxDOT and the city of Austin. The city, in addition, covered the $2.2 million cost of design and environmental study and clearance of the entire mile-long project.
After the bike bridges open, the city will find out if the theory is correct behind what is now a $14.1 million undertaking. The point of the bridge over Barton Creek, first suggested about 2005, is that the yawning greenbelt, and the necessity for cyclists to brave MoPac to cross it, has suppressed a significant yearning by Southwest Austinites to come north on two wheels. How large is this untapped corps of human-powered commuters?
“Because there has never been any sort of facilities like this in the area, it’s difficult to predict usage,” Crager said. “We expect there to be hundreds if not thousands of cyclists using it” once the full project is done.
The northern section was added to the project after the city, with some prodding by TxDOT, decided that asking cyclists to cross Loop 360 at ground level (at the frontage road traffic light) would be dangerous and would blunt the stimulative effect of having the expensive bridge over the creek. So the project, originally estimated to cost about $5 million, was expanded to include the bridges over Loop 360.
The near-tripling of the cost grew not only from the addition of the Loop 360 bridges, but also from design changes to the Barton Creek bridge. And construction costs in Austin have trended upward since the original estimates.
The bridges and connecting path to a sidewalk on MoPac’s northbound frontage road, and then the Butler Hike and Bike trail beyond, will mean that cyclists will be able to ride off street all the way from U.S. 290 to downtown Austin.
Ultimately, Crager said, city officials hope to have an off-street path all the way past the “Y” at Oak Hill to the Austin Community College Pinnacle campus. And the early designs for the South MoPac toll lane project, currently in legal limbo, includes the addition of “shared use” paths all the way to Circle C.
Work on the Barton Creek bike bridges project began in early 2014 and was originally expected to be done by the end of 2015. But underground “footings” of the towering columns supporting the Barton Creek bridges had to be redesigned after workers discovered that bedrock on either side of the creek was deeper underground than expected.