Tag Archives: traffic safety

What Do I Think of the Diverging Diamond Interchange?

 

By Dom Nozzi

Febuary 2, 2017

Superior, Colorado built a “diverging diamond” interchange that opened in October 2015. It was only the second such interchange to ever be built in Colorado. Traffic engineers are imagessinging its praises throughout the nation. A newspaper article appearing in the February 2, 2017 edition of the Boulder Daily Camera fawned over the fantastic new addition to the region’s transportation system.

I am not joining the engineers or the newspaper in their love affair with the design.

Instead, I find such designs a colossal waste of money – money that could have been used for, say, transit. They are also a colossal waste of land. An entire city could fit inside one of these intersections.

The diverging diamond is a boondoggle for those reasons. But it is also a blunder because they promote increased per capita car travel. Why? In part because they are nearly 51df393d218c6-imageimpossible to cross by foot or bicycle. And in part because in the long run they will further disperse land development in a more sprawling way. Those increased distances will make it increasingly impractical to walk, bicycle or use transit.

Ironically, the major justification for the car-only design is that it briefly reduce intersection congestion, which will initially save a few seconds of motorist time (think of the fiscal irresponsibility of spending millions of public dollars spent to save a few seconds temporarily). Ironic because by artificially inducing more car trips than would have occurred had the diverging diamond not been built, the design will lead to MORE traffic congestion and MORE time delay for motorists in the long term (both at their location and areas in the region).

To hide the embarrassing fact that the millions spent ($14 million in this case) to briefly save a few seconds of time, the publicly proclaimed explanation is that it will improve safety. For the conventional traffic engineer, “improved safety” actually means that motorists can now drive faster and more inattentively with less fear of crashing. No mention is made of the fact that the intersection is much less safe for pedestrians or bicyclists, or that faster, less attentive driving is very dangerous for everyone.

The diverging diamond, therefore, is an excellent example of the century-long failure by conventional traffic engineers to understand induced car trips that are created by (briefly) reducing traffic congestion with these designs. There is a reason, after all, that many researchers repeatedly urge us to understand that it is impossible to build our way out of congestion. It is like loosening your belt to solve obesity.

But wait. There’s more.

Not only is the diverging diamond a boondoggle in the above mentioned ways. It also damages our world by adding more auto emissions into our air (by increasing per capita car trips) and reducing potential tax revenues in the region (by encouraging dispersed rather than compact land use patterns).

Future generations will shake their heads in disbelief over why our generation built these monstrosities.

There is one tiny upside to this overwhelmingly negative idea: it produces future jobs for people hired to remove these mistakes after we regain our senses.

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Is Traffic Calming Unsafe?

 

By Dom Nozzi

November 1, 2016

On October 5th, David Wagner alleged in the Boulder CO Daily Camera that traffic calming (which uses street design to slow cars to safe speeds) does not improve safety, yet significantly degrades fire safety (due to slower response times).

This is a red herring.

A study by Peter Swift conducted in Longmont CO found that when cities use excessive dimensions for roads to reduce fire truck response times, there is a net LOSS in overall safety.

Why?

Because those road dimensions lead to a large increase in car crashes, and the number of injuries and deaths caused by that increase in car crashes far exceeds any decrease in fire injuries/deaths due to allegedly slower fire truck response times. Dan Burden – a national traffic calming expert and son of a fire chief – disputes the claim that fire truck response 8330087time is significantly slowed. Boulder would benefit from having Burden conduct a traffic calming audit with the Boulder fire department, and demonstrate designs that slow cars without slowing fire trucks.

Swift’s study shows that safety is far better served when a community focuses on the much broader question of LIFE SAFETY rather than the subset of FIRE SAFETY.

Something not easy to measure in studies: When car speeds are not slowed by traffic calming measures, a large number of potential bicyclists and pedestrians are deterred from biking or walking (particularly children and seniors) due to perceived danger of high car speeds. Conversely, slow car speeds effectively recruit large numbers of cyclists and peds. Studies show that a society where there is less walking and cycling — and the more driving — public health declines and deaths increase.

The Transportation Advisory Board has been inundated with dozens of emails from citizens throughout the city pleading for the Board to calm their neighborhood streets due to dangerous speeding and cut-through traffic.

They would beg to differ with Mr. Wagner’s remarks.

 

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Promoting Traffic Safety

 

By Dom Nozzi

August 20, 2016

After three years of trying, I have finally been given the opportunity to give a presentation to the Boulder transportation advisory board – of which I have been a member. The topic will be on traffic safety, and I will be making the presentation in either early September or early October.

I decided one point I’d like to make is that if anything, streets have become much less safe than they were in the past – despite decades of often aggressive, extensive, expensive boulder-traffic-safetysafety efforts. This morning, I looked for a chart showing the trend in the number of annual deaths on US roadways. I have included a few charts from Wikipedia in this blog. “Annual Traffic Deaths” shows the crazy high number of annual deaths.

But the “Annual Deaths Per Mile Driven” chart shows that we are making a lot of progress on safety! I was surprised and realized I’d have to revise my presentation.

Then I came across a “Traffic Deaths” essay.

I learned from the essay that several decades ago, the auto folks needed to find a way to address the great alarm on the part of many Americans when they saw the huge number of traffic deaths. The solution to this PR problem – to head off serious efforts to reduce car dependence in our society – was to convey deaths based on MILES DRIVEN. It turns out that applying “miles driven” as a way to measure deaths is quite misleading. After all, if we used miles traveled, the space shuttle would be the “safest” way to travel…

Using that metric, the auto folks were able to reduce alarm (and meaningful efforts to reduce car dependence), because the metric shows improving traffic safety. Now we can sidestep the thought that 30,000 to 40,000 traffic deaths per year is barbaric (and demands our society reduce car use) and instead focus safety on individual motorist mistakes or mechanical solutions (which does almost nothing to correct this shocking, unacceptable road carnage problem).

One of my points about traffic safety is that our forgiving roadway design induces dangerous and growing levels of inattentive driving and excessive speeding. I believe inattentive driving and speeding are epidemic mostly because of our decades of employing forgiving roadway design. But if this is true, why does the chart show a decline in deaths since 1970?

My explanation is that while roads ARE more dangerous today than in the past, much of the reduction in deaths is associated with making cars (and, therefore, the motorists bike-car-crash1inside them) safer with such things as seat belts, air bags, and aggressive efforts against drunk driving – not to mention our removing a lot of trees and other “hazards” from near the side of roads.

I found another chart that shows a big increase in bicyclist deaths since the 1970s. That can partly be explained, I guess, by the growth in cycling since then, but I think it is also compatible with my belief that roads are more dangerous today. Motorists are safer in certain ways, but the growth in inattentiveness and speeding are leading to motorists killing more people bicycling.

In sum, it is clear to me that our roads need to be substantially redesigned to obligate slower, more attentive driving by motorists through various traffic calming, as well as reductions in the size of roadways and intersections. More warning signs, warning lights, warning paint, warning education, and warning enforcement has utterly failed to make our streets safe.

It is way past time to get serious and redesign our appallingly dangerous roadway system.

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Traffic Safety in Boulder

By Dom Nozzi

As a member of the Boulder Transportation Advisory Board, I am alarmed  by the recent uptick in serious injuries and deaths caused by vehicle crashes on roads in our area. I am ashamed that our community seems poised to respond with the same old song and dance.

Three factors are primarily responsible for enormous traffic safety problems that persist in Boulder.bike-car-crash1

First, roadways and intersections have grown enormous in size in Boulder. Roads such as Arapahoe, Canyon, Colorado, 28th Street, and Baseline now have such a large number of travel lanes and turn lanes that pedestrians and bicyclists must now cross a huge distance made more daunting by the high speed car traffic on these roads. Anything more than 3 or 4 lanes is extremely dangerous to cross, and these roadways now contain up to 7 or 8 lanes. This oversizing has been driven by an effort to promote “free-flowing” traffic – even at rush hour. Given the enormous size of cars (a person consumes 17 to 100 times more space in a car than in a chair), and the large number of regional commuters coming to Boulder each day, retaining “free-flowing” traffic — even at rush hour — is a recipe for finding yourself oversizing streets and intersections. Boulder has certainly done that. By doing so, Boulder now has a number of oversized roads that are too big for a city, too big for safe bicycling or walking, and too big to have any reasonable chance to achieve an emerging plan of “vision zero” for crashes (reducing the number of traffic deaths and serious injuries to zero). To put the oversizing problem in perspective, if we want to carry 50,000 people per hour in each direction of a road, we’d need one lane worth of road if they are carried by train, two lanes if carried by bus, and 18 lanes if carried by car.

Second, it is important to note that at the dawn of the auto age a century ago, nearly all American cities – including Boulder — adopted forgiving roadway design. Forgiving design “forgives” a motorist for driving too fast or not paying attention by increasing the width of travel lanes, adding travel lanes, and removing “obstacles” from the areas flanking roads (trees, buildings, etc.). The naïve thought was that this would reduce the number of things motorists would crash into.

The unintended consequence, however, was that this design significantly increased motorist speeding and inattentiveness, as a motorist tends to drive as fast and as inattentively as the roadway design allows. The result of forgiving design is that there is an epidemic in motorist speeding and inattentiveness – aggravated by the concurrent epidemic in sleep deprivation that causes most all of us to occasionally fall asleep at the wheel.

Third, for 100 years, nearly all US cities — every few years — have “renewed their efforts” to improve traffic safety. We “redouble our work” to institute the “Five Warnings:”

Warning signs are installed. Warning lights are erected. Warning paint is painted. Warning education is introduced. Warning enforcement is pushed.

After all those campaigns over the past century have been waged, what has been the result? We have, today, the most dangerous streets we have ever had. Clearly, the Five Warnings have been ineffective.

For several decades, we have been so successful in providing for fast, unobstructed travel by car that it has substantially undermined transit ridership, walking, and bicycling. “Danger” is an all-too-frequent reason given in surveys for not bicycling, for example.

Wide travel lanes and multi-lane roads exert a nearly irresistible influence over a motorist. Even motorists who are not inclined to drive fast creep up to highway speeds. Amplifying this problem: large numbers of drug- or alcohol-impaired drivers, sleep-deprived drivers, and time-starved drivers. These factors are a dangerous mix, as they induce a great deal of high-speed, inattentive, reckless driving.

As noted above, making a street “safer” too often increases vehicle speeds, which makes the streets less safe – particularly for pedestrians and cyclists. One result: a disproportionate number of serious injuries and deaths in Boulder are suffered by pedestrians and bicyclists. About 40 percent of all children killed in motor vehicle crashes nationally are killed while walking or riding a bicycle.

Measured by “years of life lost,” motor vehicles fatalities rank third.

Since 1930, over 30,000 Americans die in motor vehicle crashes annually.

This is appalling. And should be completely unacceptable to any civilized society.

The Importance of Traffic Calming

One of the most common requests by citizens to our Board is the need to reinstate the neighborhood traffic calming program that was defunded in the early 2000s. Speeding, cut-through vehicles are a serious problem for many neighborhoods. Such traffic discourages bicycling and walking, substantially increases noise pollution, endangers our most vulnerable (seniors, children, the handicapped, and pets), is a primary cause of loss of neighborhood quality of life, and fuels opposition to infill development.

Traffic calming, which is a street design that obligates motorists to drive more slowly and attentively, has been shown to dramatically improve street safety. Desirable design examples include traffic circles or roundabouts, curb “bulbouts” (which reduce the width of the street), and removal of travel lanes or turn lanes. Roadway geometry in safety-sensitive areas, such as schools, needs to keep speeds near 20 miles per hour. Traffic circles reduce crashes by 50 to 90 percent, compared to two-way and four-way stop signs and traffic signals, by slowing cars and reducing the number of conflict points.

Note that in general, “horizontal calming interventions” such as circles and neck-downs are more desirable than “vertical calming interventions” such as speed humps. Among other things, humps cause noise pollution problems and can dangerously impede fire truck and other emergency vehicle response times.

Motorists are more likely to collide with pedestrians at higher speeds. At 60 miles per hour, the field of vision of the motorist is two-thirds less than at 30 miles per hour. In addition, the probability of a pedestrian being killed is only 3.5 percent when a vehicle is traveling at 15 miles per hour, but jumps to 37 percent at 31 miles per hour and 83 percent at 44 miles per hour.

Despite the conventional wisdom, stop signs do not affect overall speeds or control speeding. Posting lower speed limits and enforcing them is not sufficient to achieve needed reductions in speeding. Modest physical reconfiguration of streets is the only reliable and cost-effective way to slow and control inattentive speeding.

Calming helps reduce neighborhood noise pollution. Higher speeds substantially increase noise pollution.

The Federal Highway Administration (FHA) notes that the importance of reducing traffic speed cannot be overemphasized, and has stated that traffic calming is one of the more cost-effective ways to promote pedestrian and bicycle use in urban and suburban areas, where walking and bicycling are often hazardous and uncomfortable. And as for children, Stina Sandels, a world authority on children and road accidents, says that the best road safety education cannot adapt a child to modern traffic, so traffic must be adapted to the child.

Fortunately, there are effective street design tactics to substantially increase road safety, and these methods can be deployed without significantly slowing emergency vehicle response times.

I urge Council to restore funding for neighborhood traffic calming. Since the City does not have the authority to introduce safe, speed-slowing designs on larger state roads, I urge Council to lobby the State legislature to give Boulder the authority to do so.

Summary

How about if we do something effective to improve traffic safety?

  1. What if, instead of pursuing the ruinous objective of maintaining “free flowing” traffic (even at rush hour), we start the process of shrinking the size of the many over-sized roads and intersections in Boulder to induce slower, more attentive driving? (not to mention a financially healthy atmosphere for retail, and a higher quality of life for homes)
  2. What if, instead of continuing the counterproductive “forgiving” street design paradigm, we revise Boulder’s street design manuals to obligate slower speed, attentive driving? (including a restoration of the Boulder traffic calming program)
  3. What if, instead of continuing the failed, century-long effort of using the “Five Warnings” — which amounts to a form of blaming the pedestrian and bicyclist victim — we put more of the onus on traffic engineers to design streets to obligate safe motorist behavior? How about if we return our transportation system to people, instead of our on-going effort to be a doormat for ruinous levels of car travel?

In addition to the above, I recommend more compact development in appropriate locations, sponsoring a transportation safety speaker series, and more street connectivity.

We have a duty to make Boulder streets much safer.

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What Are the Obstacles to Making Our Streets Safer?

By Dom Nozzi

July 1, 2016

There have been a great many traffic injuries and deaths in the Boulder area in recent weeks. This is a terrible tragedy and tracks what is happening nationally. If we are to call ourselves a civilized society, there are effective things we must do to make our streets safer.

A very large percentage of neighborhood streets in Boulder (and the region) are excessively wide, which induces excessive driving speeds and dangerously inattentive driving. Boulder needs to redesign many of these streets to be safer. Good tactics are the common and effective traffic calming measures which narrow the street (yet still allow adequate emergency vehicle response times), including the use of slow streets, give-way streets, design-for-slow-streetsand shared streets. Each of those designs deliver slow design speeds which are crucial for neighborhood safety. A quick, easy and low-cost way to create slower, more attentive neighborhood streets is to allow and encourage a lot more on-street car parking, in addition to bulb-outs, traffic circles and chicanes. Slow speed neighborhood streets dramatically improve neighborhood quality of life and safety, and effectively promote more walking, bicycling and sociable neighborhood interactions.

An extremely common suggestion to address dangerous speeding is to lower speed limits. But mounting signs with lower speed limits, as nearly all traffic engineers know, is highly ineffective unless we also redesign the street. The typical motor vehicle speeds are generated by the design speed of the street rather than speed limit signs (which are so commonly disregarded that many derisively call them “suggested” speed limits). It is also unfair to the motorist to install a speed limit sign that is far below the street design speed. When the street design strongly encourages motorists to drive at higher speeds than the speed limit, a large number of speeding violations and tickets result.

I have been a bicycle commuter in a great many cities in the US, and in my opinion, the state highways in Boulder (in particular, Broadway, Canyon, and 28th St) are among the most hostile, deadly state roads I have ever bicycled or walked. The state highways in Boulder are death traps not only for bicyclists, pedestrians, and transit users, but also motorists. Those streets (and their huge intersections) are too big and therefore too high speed to be located within a city. It is important to note that city health is promoted with slow speeds, so these state highways are undermining the quality of life in Boulder.

The fierce opposition to the Folsom street reconfiguration project, as well as opposition to other safety and quality of life street redesign measures such as the traffic calming program in the 1990s, suggests that many in the Boulder population are not ready to accept enactment of street designs which effectively improve street safety and quality of life.

Even in Boulder, it is nearly impossible for the vast majority to travel anywhere without a car. American cities (including Boulder) are designed so that regular, safe, convenient travel by bicycle, walking, or transit is out of the question for almost all of us (mostly because roads are too big and distances are too large). That means, inevitably, that large numbers of people are obligated to drive a car even though it is too dangerous for them to do so. They have had too much to drink. Or they are angry or emotionally upset. They are distracted or exhausted by their multi-tasking, busy lives. Or their driving skills are questionable due to age or poor eyesight or other factors. In a society where nearly all trips must be made by motor vehicle, this problem is large and unavoidable.

It is incumbent on us, therefore, to design our streets and communities to be more compact and slower in speed. Otherwise, dangerous streets and unacceptably high numbers road crashes will always be a part of our lives.

 

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What Are the Obstacles to Making Our Streets Safer?

 

By Dom Nozzi

July 1, 2016

There have been a great many traffic injuries and deaths in the Boulder area in recent weeks. This is a terrible tragedy and tracks what is happening nationally. If we are to call ourselves a civilized society, there are effective things we must do to make our streets safer.

A very large percentage of neighborhood streets in Boulder (and the region) are excessively wide, which induces excessive driving speeds and dangerously inattentive driving. Boulder needs to redesign many of these streets if there is to be any chance of making the city street system anywhere near safe. Good tactics are the common and effective traffic calming measures which narrow the street (yet still allow acceptable emergency vehicle response times), including the use of slow streets, give-way streets, and shared streets. low-speed-streetEach of those designs deliver slow design speeds which are crucial for neighborhood safety and quality of life. A quick, easy and low-cost way to create slower, more attentive neighborhood streets is to allow and encourage a lot more on-street car parking, in addition to bulb-outs, traffic circles and chicanes. Slow speed neighborhood streets not only dramatically improve neighborhood quality of life and safety. They also effectively promote more walking, bicycling and sociable neighborhood interactions.

An extremely common suggestion to address dangerous speeding is to lower speed limits. But mounting signs with lower speed limits, as traffic engineers know, is highly ineffective unless we also redesign the street. The typical motor vehicle speeds are generated by the design speed of the street rather than speed limit signs (which are so commonly disregarded that many derisively call them “suggested” speed limits). It is also unfair to the motorist to install a speed limit sign that is far below the street design speed. When the street design strongly encourages motorists to drive at higher speeds than the speed limit, a large number of speeding violations and tickets result.

I have been a bicycle commuter in a great many cities in the US, and in my opinion, the state highways in Boulder (in particular, Broadway, Canyon, and 28th St) are among the most hostile, deadly state roads I have ever bicycled or walked. The state highways in Boulder are death traps not only for bicyclists, pedestrians, and transit users, but also motorists. Those streets (and their huge intersections) are too big and therefore too high speed to be located within a city. It is important to note that city health is promoted with slow speeds, so these state highways are undermining the quality of life in Boulder.

The fierce opposition to the Folsom Street reconfiguration project in 2015, as well as opposition to other safety and quality of life street redesign measures such as the traffic calming program in the 1990s, suggests that many in the Boulder population are not ready to accept enactment of street designs which effectively improve street safety and quality of life.

Even in Boulder, it is nearly impossible for the vast majority to travel anywhere without a car. American cities (including Boulder) are designed so that regular, safe, convenient travel by bicycle, walking, or transit is out of the question for almost all of us (mostly because roads are too big and distances are too large). That means, inevitably, that large numbers of people are obligated to drive a car even though it is too dangerous for them to do so. They have had too much to drink. Or they are angry or emotionally upset. They are distracted or exhausted by their multi-tasking, busy lives. Or their driving skills are questionable due to age or poor eyesight or other factors. In a society where nearly all trips must be made by motor vehicle, this problem is large and unavoidable.

It is incumbent on us, therefore, to design our streets and communities to be more compact and slower in speed. Otherwise, dangerous streets and unacceptably high numbers road crashes will always be a part of our lives.

 

 

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Improving Traffic Safety in Boulder Colorado

 

By Dom Nozzi

July 12, 2016

In recent weeks, I have been alarmed and saddened by the uptick in vehicle crashes in the Boulder area that have led to serious injuries and deaths. I was touched and encouraged last night by the strong showing of support for a big improvement in traffic safety for Boulder at my Boulder Transportation Advisory Board meeting (of which I am a member).

I have been a bicycle commuter since I was a young boy. I have spent the past 35 years both academically and professionally in the field of transportation – particularly in the area of transportation safety for bicyclists, pedestrians, and motorists.

That background has made traffic safety one of my most important objectives of advocacy, and a primary reason why I was interested in serving on Boulder’s Transportation Advisory Board.

I think it is very important that our Board respond to the heightened community concerns about the state of traffic safety in Boulder with support for an agenda we as a Board recommend to City Council.

Indicators of Traffic Safety

If we are to make any meaningful progress in reducing the number of serious crashes in Boulder, we must be able to measure trends to know whether our safety measures are succeeding. In my view, there are three primary measures:

(1) Annual Number of Serious Crashes. This measure is readily available and has not shown any substantial downward trend for a long time.

(2) Average Speed of Motor Vehicles. This measure is difficult to quantify, but given long-term trends in conventional street design, average speeds are likely to have plateaued at a high level or has increased over time. We know that average motor vehicle speeds are strongly correlated to the number of severe crashes.

(3) Level of Motorist Inattentiveness. At least one study I have seen reports that approximately 80 percent of all motor vehicle crashes are due to inattentiveness. Unfortunately, it is nearly impossible to measure the level of inattentiveness. Nevertheless, it is extremely likely that motorist inattentiveness has skyrocketed in recent decades due, again, to long-term trends in conventional street design, as well as an American lifestyle that has grown increasingly busy and exhausting.

Street engineering and Safety in Numbers are head and shoulders above other common safety efforts, in terms of effectiveness. Indeed, Boulder’s laudable goal of achieving Vision Zero will not be meaningfully approached without street engineering reform.

As has been said many times, good street design produces desirable and safe travel behavior.

By far, the most effective way to increase road safety is to engineer Boulder streets to reduce average car speeds and increase motorist attentiveness. Traffic engineers are well-versed in how to do this.

In particular, minimizing the curb to curb distance on streets and intersections is essential.

The Same Old Song and Dance

For the past century, the status quo for Boulder and the State of Colorado has been to employ warnings, and the “forgiving street” paradigm for road safety.

Conventional warning methods (the “Five Warnings”) long used in Boulder (and other cities) include Warning Paint, Warning Lights, Warning Signs, Warning Education, and Warning Law Enforcement. These warnings are almost entirely ineffective when roads and intersections are oversized, and after a century of employing these warnings, they now suffer from severely diminished returns.

Street design is “forgiving” when street design “forgives” the motorist for driving too fast or too inattentively.  This design paradigm strives to minimize the likelihood of motor vehicle crashes by seeking to minimize the consequences of driving too fast or too inattentively. Forgiving design has converted a large number of Boulder streets into high-speed highways rather than the local and slower streets they should be. The following are design examples:

  • Travel lanes that are extremely wide;
  • Roads that contain an a large number of travel lanes or turn lanes;
  • A large vision triangle at intersections;
  • A large clear zone on the sides of roads (removing trees or other stationary objects);
  • Super-elevating road curves;
  • Intersections with a large turning radius.

The following links describe this strategy.

http://www.pps.org/blog/what-can-we-learn-from-the-dutch-self-explaining-roads/

https://www.cnu.org/publicsquare/new-science-street-design

http://nacto.org/docs/usdg/design_safe_urban_roadsides_dumbaugh.pdf

Today, following several decades of forgiving street design, average car speeds are higher and motorist inattentiveness is a far worse public safety problem. In many ways, forgiving street design is the reason for these higher speeds and increased inattentiveness.

Fortunately, Boulder is beginning to move toward a new street design paradigm. But relatively narrow, attentive streets such as those found in Boulder’s Holiday neighborhood are the rare exception rather than the rule.

Nearly all of the recent, significant car crashes in Boulder have occurred on major roads. Our dilemma is that a large number of Boulder residents seem unwilling to humanize such roads to make them safer (reducing dimensions to reduce car speeds, for example). And there remains a strong desire to maintain relatively high speed, free-flowing traffic on such roads, which is in direct conflict with safety objectives. One commonly heard strategy for those who oppose the safety redesign of major roads is to recommend that bicyclists avoid such roads. But this is naïve, in conflict with healthy city objectives, and discriminatory.

It is also naïve to think that Boulder can ever comprehensively provide such things as protected bike lanes, off-street paths, and safe pedestrian crossings for the enormous number of destinations that bicyclists and pedestrians need to access. While protected lanes and safe pedestrian crossings have a role to play, it is incumbent on us as a city to recognize that over-sized, high-speed highways are inappropriate in cities and must be reformed to be compatible with safety objectives and healthy city objectives. Many other cities have done this. There is no reason that Boulder cannot follow that path.

Cities thrive when streets induce slower, more attentive travel speeds, and when streets safely allow travel by pedestrians and bicyclists. In part, such design advances city health by promoting “agglomeration economies,” where people and businesses are induced to be compactly drawn to each other (or co-located near each other).

Ruinously, nearly all Americans have aggressively worked for several decades to ensure that communities enable higher car speeds.

Cities are degraded and unsafe when large, high-speed highways intrude into them. Such design has a repelling influence on people and businesses that induce them to disperse and separate from each other. Social capital and a sense of community thereby decline as well.

Toward a New Vision for Traffic Safety

For Boulder to make meaningful progress in reducing serious motor vehicle crashes, new methods must be employed in the future.

It has become increasingly clear after decades of use that the “Five Warnings” are not working well.

Nor are the forgiving street tactics.

Instead, there is a growing recognition of the need for street design that obligates slower motor vehicle speeds and more attentive driving. This design is by far the most effective way to increase road safety in Boulder. Traffic engineers are well-versed in how to do this.

Given the above, I have proposed that the Boulder Transportation Advisory Board support the following. Admittedly, they are largely long-term tactics, but after 100 years of using counterproductive approaches, it should not surprise us that there are few if any quick fixes.

  1. The City should ramp up its program to redesign streets. Lane repurposing should remain in the city toolbox for roads that contain a large number of travel lanes. Major roads should be Complete Streets. Local and collector neighborhood streets – which today are excessively wide and unsafe on a large percentage of streets — should be incrementally redesigned to be slow streets, shared streets, and give-way streets. road diet before and afterOn-street parking should be employed much more often (and retained where it already exists), and existing one-way streets should be converted back to two-way operation (one-way streets are exceptionally dangerous and inconvenient for bicyclists – not to mention their toxicity to retail and residences). Lane widths and turning radii at intersections need to be incrementally reduced as well.
  1. The City should restore funding or find new funding to finance a ramped up street redesign program to create low-design-speed streets.
  1. The City should ratchet down the use of the “Five Warnings”: warning signage, warning lights, warning paint, warning education, and warning law enforcement. These tools have been over-used to the point of being a distracting, counterproductive tactic that reduces safety.
  1. To take advantage of the powerful safety benefits of Safety in Numbers, the City should redouble efforts to significantly grow the number of bicyclists and pedestrians and transit users. Tactics can include pricing, Eco-Pass provision, compact development, and parking reform, for example.
  1. The City should incrementally strive to increase street connectivity. By having more connected streets, bicyclists and pedestrians can better avoid using more dangerous major streets.
  1. The City should put a moratorium on the creation of new double-left turn lane intersections, and incrementally convert double-left turns to single-left turns (removal of left- and right-turn lanes is particularly important in the Boulder town center). City data shows that major intersections are the location of an enormous number of crashes. Double-left turn lanes create huge intersection sizes and high-speed, inattentive driving. Such intersections are far too scary/dangerous for all but the most skilled, courageous bicyclist, and the crossing distance for pedestrians makes these intersections very undesirable – particularly for seniors, the disabled, and children. Double-left turn intersections are in direct conflict with safety objectives and efforts to leverage Safety in Numbers.
  2. The City should strive to minimize the size of service vehicles and buses so that larger vehicles do not become an excessively large design vehicle. When emergency, service and delivery vehicles are relatively large, the excessive size becomes the “design vehicle” that road engineers use, which ends up driving the dimensions of city streets. Huge vehicles should not be determining the size of our street infrastructure. Street sizing in a town center should instead be based on safety for pedestrians and bicyclists, human scale, and overall quality of life.

The time for Boulder to start using effective tactics for improved traffic safety is way overdue.

 

 

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