On the Importance of Ratcheting Down Speed and Size

By Dom Nozzi

Dangerous, high-speed, reckless, inattentive driving is now of epidemic proportions in nearly every community in America. Motor vehicle collisions with bicyclists and pedestrians have remained at unacceptably high levels for several decades. The hostile, high-decibel conditions delivered by high motor vehicle speeds on American roads has led to costly, growing efforts to “buffer” homes and businesses from these frenzied, perilous, increasingly wide suburban highways. Fortressing efforts such as berms, masonry walls, large building setbacks, thick vegetation, and grade separations have all been tried. Those houses and commercial establishments which are unable to tolerate these increasingly roaring raceways are being abandoned or relocated to outlying, sprawling locations. Much of this abandonment explains the widespread decline of American Main Streets in the 60s, 70s and 80s.

The quandary is vividly clear: More and more, we are horrified to discover that high-speed motor vehicles are simply incompatible with a livable community for humans, despite all our efforts to separate ourselves from the growing speedways that are engulfing us.

High-speed roads are not only inhospitable to houses and businesses. They also create a “barrier effect” in which it is increasingly difficult to use such roads for bicycling and walking (or even transit). Consequently, per capita motor vehicle trips grow in the community. In combination with the higher speeds, fuel consumption and air pollution rise significantly.

As an aside, it should be noted that perhaps the most important reason that high-speed roads discourage and endanger bicycle and pedestrian trips is the “speed differential” between motor vehicles and those bicycling or walking. When motor vehicles move at modest speeds of, say, 15 mph, the speed differential between vehicles, bicycles and pedestrians is relatively small. Motorists have more reaction time. Bicyclists and pedestrians feel more comfortable next to slower speed cars, with one important beneficial result being that a MUCH LARGER number of residents in the community feel safe bicycling or walking.

Collisions with cars are also more likely to result in survival.

These super-fast highways are not only deadly for pedestrians and bicyclists. They also become death traps for crossing wildlife, as higher speeds lead to a dramatic growth in “road kills.”

What are the origins of high-speed roads?

Motor vehicles, by their nature, require an enormous amount of space. Indeed, a car takes up so much space that roads become congested with cars with only a modest number of cars on the road. Because roads become congested so quickly when the car is used for transportation, the advent of the car in the early part of the 20th Century soon led road planners to push for wider road lanes (from, say, 8 ft wide to 12 ft wide) and an increase in the number of travel lanes (from, say, 2 lanes to 4 lanes).

The growth in the size of roads led to an inexorable, vicious cycle. Because an emphasis on expanding and promoting the car “habitat” (roads and parking lots) inevitably leads to a decline in the quality of the human “habitat” (neighborhoods and Main Streets), the early part of the 20th Century witnessed a growing desire to flee the increasingly congested, dirty, degraded in-town locations for the “greener pastures” of suburban life in peripheral locations.traffic jam on huge hwy

Most humans lead busy lives. They have what is known as a “travel time budget”, wherein there is a desire to maintain an equilibrium in the amount of time devoted each day to regular, round-trip travel (such as the commute to work). Cross-culturally and throughout history, we have learned that this travel time budget, on average, is approximately 1.1 hours per day.

The growing desire to escape the cities being degraded by aggressive, high-speed motor vehicle travel meant, primarily, that there was a pressing need to widen roads to enable a growing number of cars to travel at high speeds for greater distances (in order to maintain the 1.1-hour travel time). Unfortunately, this sets into motion a downwardly spiraling vicious cycle in which high-speed motor vehicles bring us toward increasingly degraded cities, which pushes a growing number of us to flee to peripheral locations. The growth in peripheral residences leads to a growing popular demand for bigger, faster roads.

And each time we build bigger, faster roads, we degrade that ring of city growth (by creating a congested, unpleasant car habitat), which pushes a growing number of us to flee to a even MORE peripheral location in a never-ending process.

What can a community do to escape this downward spiral?

To escape this spiraling community dispersal (driven by a declining quality of life), the path is clear.

Slow down motor vehicle travel.

We are fortunate that while nearly all American adults now use a car for nearly every trip, it is not at all necessary for us to strive for the impossible, undesirable objective of “getting rid of all cars.” The good news is that we can keep our cars. But we need to become more the masters of our cars rather than their slaves. That means we need to design our communities and our roads to obligate motorists to be better behaved (primarily by driving at more modest speeds and doing so more attentively). When motor vehicle speeds decline, and motorists drive more attentively, we find that community quality of life can be maintained, and even improved, DESPITE the presence of cars.

Another crucial aspect of “well-behaved” motor vehicles is to return to the tradition of building communities that provide travel choices, so that folks are not required to make ALL trips by motor vehicle. Creating travel choice means a return to the tradition of establishing “mixed use,” more compact neighborhoods. Homes are co-mingled with modest shops, offices, civic buildings, and pocket parks. This sort of traditional, mixed use neighborhood design substantially reduces trip distances, which means that walking, bicycling and transit use become more feasible and likely. The short distances and mixed uses also means that streets do not need to be over-sized with 11- or 12-foot wide travel lanes or 4- and 6-lane roads.

And these factors contribute to a crucial, inevitable result: slower, more attentive motor vehicle travel (which leads to safer, more livable driving — and driving that is OPTIONAL rather than REQUIRED).

For most communities, design imperatives are therefore as follows:

First, neighborhood residential densities in community core areas need to be high enough to support a healthy, frequent transit service, and smaller, neighborhood-based retail shops. A general rule of thumb is that this density needs to be at least 6 to 8 dwelling units per acre. Higher-density, mixed use communities promote more modestly sized neighborhoods and communities.

Second, communities need to continue the nation-wide trend of installing traffic calming designs, and doing so throughout the community. Traffic calming has been found to deliver extremely cost-effective benefits to communities that employ them. Slower (“calmed”) cars means healthier, quieter neighborhoods that are particularly safer for children, seniors and pets. Air pollution declines. Walking and bicycling are encouraged (due, in part, to a reduced speed differential). Neighborhoods, therefore, with stable (or improving) property values.

Preferably, calming is done by reducing HORIZONTAL dimensions rather than using VERTICAL interventions. Desirable horizontal street modifications include reducing in the width of travel lanes, reducing the NUMBER of lanes (sometimes known as road “dieting”), using landscaped or hardscaped sidewalk bulb-outs, using modest intersection turning radii, installing chicanes, restoring on-street parking, putting in roundabouts, and installing traffic circles. Each of these treatments can effectively reduce average motor vehicle speeds while still allowing for needed, higher-speed emergency response by fire trucks, police cars, and ambulances. Undesirable vertical treatments mostly include speed humps, which are commonly used due to low cost, but which can create significant problems for emergency vehicles.

As I note above, it is important that a community seeking to slow average vehicle speeds do so throughout the community, to the extent possible.

Over the course of the past several decades, American motorists have been given the opportunity to drive mostly on what are called “forgiving streets.” The forgiving street design was born in the minds of engineers who observed car collisions with trees, other cars, and bicyclists. The “solution” seemed obvious: Remove trees, parked cars, buildings and other “obstacles” from the shoulders of the street. Increase lane width. Add additional travel lanes.

The theory was that such treatments would mean that incompetent, inattentive, higher-speed motorists would be “forgiven” if they, say, drove too fast or drove off the roadway, because there would be less “obstacles” to crash into.

What they forgot about was human nature. Humans, by nature, tend to drive at the highest possible speed that can be driven safely. Traditionally, narrow streets with on-street parked cars, buildings pulled up to the street, and street trees meant that a street could only be driven safely at, say, 20 mph. Drivers needed to drive relatively slowly, courteously and attentively (read: carefully) to safely negotiate such streets. But today, with the advent of the theory that forgiving street design increases safety, we now find ourselves, ironically, with LESS safe streets. Forgiving streets allow even inattentive, high-speed, reckless, low-skill drivers to drive safely at, say, 40 mph without crashing into “obstacles.”

The result of the forgiving street paradigm should have been predictable. Less safe, higher-speed streets increasingly filled by motorists who are using cell phones or putting on make-up as they drive. And it should come as no surprise that the forgiving street is breeding an army of incompetent drivers, since they require less skill to drive than the traditional street.

Conventional traffic engineers and elected officials were happy to learn that forgiving streets provided an additional “benefit.” Not only did we expect them to increase safety. They would also SPEED UP TRAFFIC. So support for the forgiving street was found from not only those seeking more road “safety,” but also those who live in and benefited from the construction of peripheral, sprawl housing (which is enabled by higher-speed roads).

Because nearly all of our roads have now been built to be “forgiving,” the vast majority of American drivers now have the EXPECTATION of being able to drive at high speeds AT ALL TIMES. As a result, it is essential that we ratchet down these high speed expectations by incrementally calming our roads community-wide. Having only one or a handful of calmed roads in a community does not typically work well, as most drivers in such a community will retain the expectation of high-speed driving because only rarely (if ever) will such drivers be obligated to slow down. If the expectation of high-speed driving persists, the infrequent instances of calming can result in a significant level of “road rage” (and non-compliance) by motorists who believe they have an entitlement to driving 60 mph on community roads.

Finally, it is essential to recognize that there is a growing trend by citizens and fire departments to purchase increasingly large vehicles, and doing so creates enormous obstacles for a community striving to use the important designs called for above. Why? Because large vehicles — particularly large fire trucks — almost always prevents even an informed, well-meaning community from establishing the modest street design treatments needed for livability and safety. Large vehicles stand in the way of the use of modest travel lane widths, modest turning radii, and many effective traffic calming techniques.

It is therefore essential that communities do what they can to control the growing size of fire trucks and other vehicles used in the community.

In sum, the critical needs for community protection and improvement are to design communities and their streets to create modest motor vehicle SPEEDS.

And doing so is most effectively achieved by emphasizing a control in the SIZE of motor vehicles, emergency vehicles, roads, and neighborhoods.

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