Red sidewalks are popping up around Austin. The unexpected splash of color has been catching eyes and raising curiosity. Why do sidewalks sometimes suddenly shift shades?
The mystery prompted North Austin resident Dale Ritzen to write into KUT's ATXplained project, where we answer your questions about Austin's people, places and culture.
"We kind of were curious," Ritzen said. "We noticed them ... at Allandale and Burnet Road, and also driving along Airport [Boulevard] near the Lamar [Boulevard] intersection."
Inspired by the Dutch
The simple answer: They're for bikes and scooters.
Austin has followed the Netherlands in adopting red — or terracotta, as the city calls it — to indicate protected bike lanes.
In cases where pedestrians and cyclists share a red sidewalk, like at the intersection of Allandale Road and Burnet Road, the red pavement would warn pedestrians that someone might ride by.
"We design our infrastructure for all ages and abilities, so we're not designing for the [cyclist] that's super confident in nasty traffic," said Nathan Wilkes, an engineer who works for the city on bikeway infrastructure. "We're designing for the kid that wants to get to school or the family that wants to go on a ride or someone who hasn't ridden a bike since they were a kid."
Austin's first red protected bike path was built downtown in 2012 as part of an $11 million project to rebuild all of Third Street for eight blocks from Nueces to Trinity Street. The street reconstruction was paid for with debt approved by voters in 2010.
The Third Street overhaul allowed city staff to choose any color they wanted for the bike lanes.
Around that time, the Federal Highway Administration had recently approved green as a color for bike lanes. The FHWA is the national authority on traffic signs and lane markings.
Austin uses reflective green paint to mark potentially dangerous areas where cyclists cross streets or driveways. But that pricey green thermoplastic is too costly to install and maintain along miles of city bike paths, Wilkes said. So in the early 2010s, the city experimented with a less expensive option: mixing color into the concrete.
"We were just thinking, 'How do we make concrete green?' It turns out looking like sewage," Wilkes said. "So we decided to use the terracotta for its landscape aesthetic and use the national green conflict markings through intersections."
Today, nearly 5 miles of city streets have red bike lanes on one or both sides. Adding the red pigment to the concrete increases the cost by about 10%, the city said.
A lot more red bike paths are coming.
Austin City Council doubled-down on bicycle infrastructure last month, approving an ambitious plan to build almost 1,000 miles of bike lanes over the coming decades. The $1 billion project is far from fully funded.
But the council set short-term goals. Each year, the city will build at least 5 miles of red protected bicycle lanes, five protected intersections and 10 high-quality bus stops for a cost of about $9.2 million. The protected bike lanes would cost an estimated $840,000 per mile.
'People do get confused'
While other cities — including Bend, Ore. — use red bike lanes, the color is not a standard approved by the FHWA. This unfamiliarity can lead to confusion.
Last week, Pura Luna was walking with her 8-month-old daughter down a red sidewalk along Airport Boulevard. She wasn't sure why she chose the red path over the gray one next to it.
"I don't know. I was following the red brick road today, I guess," she said, laughing.
Luna pointed out there were no bicycle symbols indicating the sidewalk was reserved for cyclists.
"People do get confused, because I wouldn't have known this was just for bikes," she said.
The city plans to add bike and pedestrian markings to bike lanes and shared-use paths along the Airport Boulevard project once the concrete construction is done.
Federal rules on pavement colors
The FHWA maintains what is known in the traffic engineering world as the Bible of Road Design, the 800-page Manual on Uniform Traffic Control Devices (MUTCD). "Control devices" are basically just road signs, lane markings, traffic signals and anything used to manage, warn or guide traffic.
"So that people do know that when they see a stop sign, you can glance at it out of the corner of your eye, and you know it's a stop sign," said Randy Machemehl, a professor of transportation engineering at UT Austin.
Violating the MUTCD comes with risks, such as legal liability in the event of a traffic crash or the potential loss of federal funding for road projects.
Colored bike lanes aren't included in the MUTCD, which was last updated in 2009. But an interim addition in 2011 said green bike lanes are allowed.
"Many people have tested many colors over the years, and FHWA always tends to come back to the green," Machemehl said.
The city argues that it's not violating federal regulations by using red bike lanes. A provision in the MUTCD does allow for colored pavement, including bricks and other types of patterned surfaces, if it's "a purely aesthetic treatment and is not intended to communicate a regulatory, warning, or guidance message to road users."
Jack Flagler, a spokesperson for the Transportation and Public Works Department, said the city's interpretation of federal rules allows for red bike lanes because the pavement isn't being used to regulate, warn, or guide traffic.
"In these cases [through intersections, driveways and ramps] we use white and green-backed pavement markings" in alignment with federal rules, Flagler said.
Machemehl, a former director of UT's Center for Transportation Research, was not convinced.
"To argue [the red sidewalk] does not provide any direction to traffic is a fairly weak argument," Machemehl said. "In my opinion, they really are control devices."
The city could have applied to the FHWA for permission to experiment with red bike lanes as a control device. Such a process can be lengthy and time-consuming, requiring collecting and analyzing data to study the effectiveness of changes. Machemehl was involved in a 2010 study for the city analyzing the effects of colored bike lanes.
The FHWA did not respond to a request for comment before this article was published.
Balancing act
The City of Austin is trying to fix gridlock by convincing more people to leave their cars at home. The biggest reason people don't opt for a bicycle is a perceived lack of safety, available evidence shows.
"People prefer off-street bike paths," said Alejandro de la Vega, the vice chair of the city's Bicycle Advisory Council. "People feel more invited to ride their bike and they feel like this infrastructure is safe."
De la Vega, who regularly bikes 6 miles to work, said he supports the red concrete paths, "as long as it's consistent, like, 'Hey, we're going to use green if it's on street, and this other color is an off-street path,' in which case it's usually less urgent for cars to be aware of what the color means."
"I like them," de la Vega said. "It's definitely a bit unusual."
Editor's note: This story has been updated to reflect that the city will be marking bike lanes along Airport Boulevard once construction is done.
