David Zipper, a journalist who frequently writes on transportation safety, just wrote for Bloomberg CityLab The Best Tactics for Tackling Speeders. The article summarizes his research briefing on MIT Mobility Initiative Tactics to Reduce Urban Vehicle Speeds.

This is timely as the City of Sacramento is updating its Vision Zero Action Plan.

The main point of the article is that speed control for safety is way more popular with society than the impression one would get from reading media, which has both a bias to highlight controversy when there really isn’t much, and the windshield bias of those who drive rather than walk, bicycle, and transit.

“What I learned surprised me. With rare exceptions, these strategies to reduce speeding are effective, often to a striking degree. And contrary to common perceptions, residents generally support them.”

He also lists a number of speed control measures, in the article, and more in the paper, which are probably familiar:

• speed humps: The City of Sacramento has certainly put in a number of speed humps. Problem is, the design slows motor vehicles only momentarily, and drivers return to their previous speed over a very short distance. The literature is variable as to whether speed humps or speed tables are more effective, but my own hours of observation indicate that tables are more effective. A speed table with crosswalk, matching the height of the curb at six inches, is far more effective than a hump at 3 inches.
• automatic traffic cameras: The City of Sacramento once had red-light running cameras, but the program ceased when the county program ceased. The city has said it will install cameras and implement a program in alignment with new state laws, however, no time frame or budget had been identified. Speed cameras have been authorized for a few cities as a pilot program, and Sacramento is not one of them.
• conversions to make one-way arterials bidirectional: The City of Sacramento has made one conversion, of 5th Street, which was converted last year. It seems successful. However, the city used this project as an excuse to install completely new signal heads and signal controllers, rather than reusing any materials. At upwards of $1M per intersection, this approach guarantees that few conversions will be done.
• adjusting traffic signalizations: The City of Sacramento has talked about this, but not done so. The ‘green wave’ used in other cities, where signals are set to average bicyclist speed of about 13 mph, are very effective at calming traffic. In the central city, signals are set to 28 mph, which encourages drivers to speed in order to beat the next signal.
• posted speed reductions: The City of Sacramento has done this for some school zones, but has refused to do it anywhere else. “Simply lowering speed limits works, too. Boston’s 2017 move to reduce its default speed limit from 30 mph to 25 mph produced a relative 29% decline in vehicles exceeding 35 mph…”
• road diets: The City of Sacramento has implemented road diets on several arterial streets, reducing the number of lanes and sometimes reducing the width of lanes. However, these are major projects that require a lot of money, grants from the federal, state or regional agencies. This greatly limits the number of roadways that can be ‘fixed’.

The article concludes with: “The missing link: policymakers courageous enough to do the right thing.”