Traffic Safety Suggestions to the Boulder Colorado Mayor


By Dom Nozzi

October 17, 2016

I met with the mayor of Boulder in October 2016 to offer my suggestions for how the City could effectively take steps to address the recent uptick in traffic safety problems in Boulder. The following are my suggestions.

Traffic calming is the first order of business. Quick and relatively low-cost calming strategies that have some effectiveness: (1) on-street parking; (2) curb bulb-outs and traffic circles (these “horizontal interventions” effectively slow cars without slowing emergency response times – particularly when those interventions use “mountable curbs”); (3) install street trees near the edge of the street (popular with neighborhoods, modest effectiveness in slowing cars and making motorists more attentive); (4) photo radar (modest effectiveness, needs to be coupled with relatively frequent fines).

We need to review the list of Big Ticket (relatively expensive) transportation projects. Can some of them be delayed or foregone and instead put the Big Ticket money into refunding neighborhood traffic mitigation (calming)? Can we alternatively find new money to add to the Transportation Department budget so we don’t have to reallocate dollars from other important transportation safety needs?

We need trend data that goes back decades. Not just a year or two. Surely this info exists for decades: (1) The number of annual car crashes citywide (or on selected streets); and (2) change in average car speed citywide (or on selected streets).

Things we probably can’t directly measure but which are nevertheless crucial: (3) change in crossing distance for pedestrians; (4) change in the amount of distracted or inattentive driving; (5) change in the number of discouraged bicycle, pedestrian, and transit trips; and (6) change in ‘near misses.’

Given the enormous number of citizens emailing the Boulder Transportation Advisory Board (TAB) I serve on –emails about the significant amount of speeding and cut-through traffic in their neighborhoods — we have a very serious problem in Boulder with dangerous car travel. The fact that a neighborhood is so often told by the Transportation Department that the neighborhood does not qualify for traffic calming is a clear sign that our qualification triggers are too high of a bar and need to be revised.

  • Lowering the trigger threshold could involve lowering speed limits (even though doing so is not an effective way to slow cars, it would allow more neighborhoods to qualify for calming – because speeding would be recorded more often);
  • Giving staff the authority to calm a street if the street width exceeds, say, 25 feet;
  • Allowing a neighborhood to qualify for calming if, say, at least 80% on a block support doing so.

About 75 percent of the emails TAB has gotten contain counterproductive suggestions for calming (for example, lowering speed limits, increasing law enforcement patrols on a street, speed humps, and stop signs).

The two biggest bang-for-the-buck transportation strategies that Boulder can deploy to improve safety, improve quality of life, promote infill, and recruit new bicyclists and pedestrians is removing unnecessary travel lanes on oversized roads and intersections; and traffic calming.

Since Boulder is admirably on a fast track to implement Vision Zero (bring traffic-related serious injuries and fatalities to zero), and since Vision Zero is an umbrella that includes major roadways (arterials and collectors), can we combine Vision Zero with Neighborhood Traffic Mitigation (calming) for faster traffic calming implementation? The City calming program only addresses neighborhood streets, while Vision Zero includes major roads. Serious car-related injuries and deaths nearly always occur on major roads. It is naïve to think that we can create a pedestrian and bicycling system that is separate from major roads. Such a separate system cannot affordably reach more than a tiny fraction of destinations that pedestrians and cyclists would like to reach.

Oversized roads, such as the 8-lane Arapahoe at 30th Street, are an example of the City striving to accommodate the huge influx of regional car trips. In part, this seems to be an “affordable housing” strategy. But 5-, 6- and 8-lane roads are too big for a city that seeks to promote safety and travel choice and compact development. Regional car trips CAN be 30th-and-arapahoe-double-leftsaccommodated with less lanes. Some motorists can opt to accept moderately slower commute times. Some motorists can choose a different route. Some motorists can drive at a non-rush hour time. Some motorists can use transit. Some motorists can live closer.

As for affordability by living in an outlying town, studies show us that this is a false economy, as the cost to live in auto-dependent locations often exceeds the cost savings from lower-cost homes.

“Slowing fire truck response time” due to calming is a red herring. There are effective ways to slow cars and increase motorist attentiveness without significantly slowing emergency vehicles. In addition, the Peter Swift 2003 study in Longmont conclusively showed that oversizing roads and intersections to reduce emergency vehicle response times results in a substantial net loss in community “life safety.” Yes, there may be a slight increase in fire-related injuries and deaths, but that increase is far exceeded by the substantial increase in car-crash-related injuries and deaths. For the best public safety results, therefore, Boulder needs to focus on “life safety,” not just the subset of “fire safety.” See:

The “Five Warnings” (more lights, paint, enforcement, education, signs) have been tried every few years for about 100 years. After all of those efforts, our streets and intersections are more dangerous than ever – largely because streets and intersections are WAY over-sized. The Five Warnings do almost nothing to make such deadly, oversized roads and intersections safe.


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Filed under Bicycling, Road Diet, Transportation, Walking

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