Angie Schmitt

Demonstrations against police brutality spilled onto streets and highways in American cities this weekend, with protesters stopping traffic in Baton Rouge, Memphis, St. Paul, Los Angeles, and Oakland.

As Milwaukee's Bublr bike-share system expands, how well will it work for lower-income residents?

The images are excruciating -- Philando Castile, bleeding to death as his girlfriend and her 4-year-old daughter look on. A cafeteria supervisor in the St. Paul School District, Castile was pulled over by officer Jeronimo Yanez in the neighboring town of Falcon Heights for having a broken taillight. Yanez fatally shot Castile after he informed the officer that he was carrying a licensed firearm then reached for his driver's license and registration, according to Castile's partner, Diamond Reynolds.

How is the U.S. doing on traffic safety?

Philadelphia's commuter rail system has been plunged into turmoil after transit officials discovered a defect in SEPTA railcars this weekend.

When she was a kid growing up in Minneapolis, biking was as natural to Alice Avidor as breathing the air. But as time went on, biking went from feeling carefree and empowering to something more like a hostile negotiation.

One of the biggest problems with a car-dependent transportation system is that cars are big space hogs. A single parking space occupies almost as much square footage as a small studio apartment. But that's just the tip of the iceberg.

Traffic fatalities in America hit a seven-year high in 2015, with pedestrians and cyclists accounting for a disproportionate share of the alarming increase, according to preliminary data from the National Highway Traffic Safety Administration.

When construction projects occupy sidewalks and bike lanes, many cities don't do anything to compensate -- forcing people to walk and bike in traffic or take long, unrealistic detours. But it's not that hard to put up safe, convenient alternate routes.

Here's a great example of a "virtuous cycle" in action: Center City Philadelphia has seen the number of parking spaces decline recently as population and jobs continue to rise at a healthy clip.