Michael Andersen, local innovation staff writer
For years, the City of Austin has been on a wonky but important quest for one of the holy grails of bike infrastructure: the perfect low-cost bike lane separator.
Every common bike lane protection option has drawbacks. Plastic posts collapse. Precast curbs are complicated to install. And lots of the other options aren’t mountable by an ambulance or garbage truck.
Now, Austin thinks it might have found the grail. Or you might call it the Goldilocks of bike lane protection: not too flimsy, not too pricy.
It’s a pre-cast concrete “button.”
Photo: City of Austin.
As you can see above, these domes can be useful for more than just marking bike lanes. Here, they combine with painted polka dots to create a low-cost curb extension to improve walking safety and separate a bike-share station from the street. As of late summer, Austin had installed more than 1,000 of them around the city and had another 2,000 in storage, waiting to be deployed.
The buttons aren’t seen as a substitute for permanent raised bike lanes like you’d see in the bike-friendlier parts of Europe, Asia or South America. But raised lanes cost hundreds of thousands of dollars per mile or more, so at best they’re likely to be installed bit by bit as roadways are rebuilt. But the buttons are clearly a step above paint when it comes to separating bikes and cars. And because it’d be possible to uninstall these buttons, they’re compatible with the quick-build project delivery concept that’s been pioneered by Austin and other cities: install projects quickly but keep tweaking them after they go in.
Each button cost Austin $11.75 before paint or installation. Including installation, Austin engineer Nathan Wilkes said, the cost per button is $20. Assuming 10-foot spacing (which Wilkes said “seems to work well”) that’s $10,000 per mile of bike lane protection. That compares to $40,000 to $80,000 per protection-mile for the durable plastic “zebra” separators developed in Barcelona, Spain, which Wilkes also describes as having “much promise.”
Here’s Austin’s official spec sheet for the concrete buttons:
The city’s biggest challenge so far, Wilkes said in an email, has been making sure the buttons stick to the surface of the road. But the city’s been getting better at that.
“We have found that if the surface is clean (repeated cleaning with wire brush and leaf blower/compressed air until no debris blows away), free of paint (direct attach to asphalt or concrete), and that the bituminous covers the full base of the button that we have had good results,” Wilkes said. “We are using bituminous dispensed out of a pushcart such as this one.”
Another downside: the buttons are just three inches tall, which Wilkes feels isn’t quite enough of a visual barrier. A 4.5-inch flat top button like the one described below, he said, would be “much closer to my ideal”:
Austin has actually installed some of these larger flat-top buttons itself, using a series of concrete casts that city staffers made themselves using a set of salad bowls from a local dollar store. But Wilkes hasn’t yet found a concrete company willing produce an entire run of the flat-top buttons. In part, that’s because concrete products require tremendous quantities to turn a profit. Compounting the problem: concrete is so heavy that shipping it for more than a short distance gets expensive, so scale is hard to achieve for any single facility.
Doug Hottel, who manages Austin’s orders as the sales manager for Trantex Transportation Products, said their manufacturer was able to make it work at the low price Austin negotiated because the button product had already been developed for use with transit projects.
“Unless it’s a big order, they’re really not that interested in doing something like this, because they don’t want to stop their production line,” Hottel said.
In other words, the main thing standing in the way of low-cost protected bike lanes may be that not enough cities are building protected bike lanes fast enough.
Update: Some readers have pointed out that this treatment doesn’t work in some cities: snowy ones. Montr?al-based Bartek Komorowski sums that situation up well:
It’s simple: snowy cities install either continuous curbs or flexible delineator posts to guide maintenance equipment. pic.twitter.com/NaNWvumHwt
— Bartek Komorowski (@CyclistBartek) November 4, 2016
The Green Lane Project is a PeopleForBikes program that helps U.S. cities build better bike lanes. Our next phase is the Big Jump Project, which will select 10 very different neighborhoods and districts and help them quickly connect biking networks. Find out how your city can apply here.