Photo: Tree-lined streets like this one have safer traffic flow than streets without trees.
By Janette Rosenbaum.
Part 1 of this article described Madison’s vegetation ordinances, how public opinion is now at odds with those ordinances, and how the ordinances are still used to enforce the preferences of the minority. This second part looks at the reasoning underlying the ordinances and their enforcement.
All cities in the United States are enabled to pass and enforce laws under what is known as the police power. This power authorizes a city to create laws that are intended to protect public health, safety, welfare, or morals.
It is doubtful whether Madison’s vegetation ordinances achieve these ends, or even whether they were originally believed to do so. Like many cities, Madison has long banned tall grass on private property. But in 1978, Madison became the first US city to reverse this ban – at least partially.
In 1976, Madison had attempted to eliminate the ban on tall grass in yards, but the effort failed, due to the concerns of those who believed tall grass would attract rats and adversely affect property values. In 1978, a compromise was reached: Madison residents would be allowed to have tall grass in their yards as part of a mindful effort to be more environmentally responsible, while tall grass resulting from neglect of property would be banned. A permitting process would be used to distinguish between one and the other.
What is fascinating is that it was already well known at the time that tall grass does not attract rats, reduce property values, or cause other negative effects commonly attributed to it. This holds true whether the tall grass is part of a well-maintained prairie, or whether it is an overgrown lawn.
40 years later, the science has not changed. There is now even more evidence – including Madison’s own experience – that no harm of any kind results from tall grass. These facts are laid out in the city’s own publications on the topic. Yet, as the city considers eliminating the permit requirement and allowing tall grass as a matter of right, opponents of the change continue to raise the discredited issues of rats and property values.
It is thus not only true that banning tall grass does not contribute to public health and safety, but that Madison has known this for decades. Other vegetation-related ordinances that are still on the books suffer from a similar problem.
One example is the “vision triangle” ordinance, which bans tall plants near intersections, or near the juncture of a driveway and a sidewalk. The ostensible reason for this is that tall plants could interfere with visibility for motorists and pedestrians, leading to accidents.
However, there is little evidence that such a risk exists. Investigating traffic accident statistics shows that relatively few accidents are attributed to poor visibility – and within the list of causes of poor visibility, plants rank very low.
The leading cause of traffic accidents is driver distraction and driver error. Research suggests that plants actually ameliorate these hazards. A concept known as Attention Restoration Theory posits that nature – including plants, especially those growing in their natural forms – is so easy for our brains to process, that looking at it actually helps us recover from the fatigue caused by activities such as reading difficult materials and planning for the future. This boost to our mental energy increases our ability to pay attention and make good decisions. In other words, there is evidence that looking at plants makes us better, safer drivers.
Further evidence for this has been found in studies specifically looking at plants and driving behavior. For example, drivers travel more slowly along tree-lined streets. Motorists on highways bordered by wildflowers find it easier to pay attention than those driving on highways with mowed edges. And sections of freeway with forested medians were found to have no more accidents than sections of the same freeway where the median was landscaped with turf grass.
While it certainly may be the case that some specific plant in a vision triangle may be creating a hazard that outweighs the benefits, applying the vision triangle ordinance as a blanket rule is in fact likely to lead to reduced traffic safety. The ordinances need to be enforced intelligently in order to serve their intended purpose.
The third article in this series will tell the story of a resident who was prosecuted for a vision triangle violation, and question whether it was legal for the city to bring this case.
Postscript: On January 3, 2017, Madison officially adopted an update to the 1978 requirement that property owners obtain a permit to have tall grass in their yard. Now, in certain limited circumstances, tall grass will be allowed without a permit. An upcoming article in this series will review the new ordinances and question whether the change will make it easier to have an environmentally-friendly yard in Madison.