Monday, May 16, 2011

Caught by the Camera

Several weeks ago, on a leisurely weekend morning drive, I exited the 101 into central San Rafael. Life was good, I was on my way home and feeling mellow. Little did I know, I driving myself right into a public health debate…I approached the traffic light at 3rd street; as I did so, it turned yellow. With a full line of sight, sparse traffic at a full stop on the other side of the intersection, and no pedestrians, I performed an incident-free rolling left turn onto 3rd street. I thought nothing of it, until a few weeks later when I received something in the mail. What, might you posit, did I acquire?

1) A letter of acclaim for a safely executed “California Coast” one-way turn.
2) A friendly reminder to come to a complete stop at all signaled intersections.
3) A not-so-friendly notice from some guy in Phoenix offering me an opportunity to appear at the Marin County Superior Court.

Well, anyone else who’s been snagged by red light camera enforcement in San Rafael knows the correct answer. This experience and its price tag (over $600 in fines and fees!) inspired me to take a close look at the rapidly growing, but controversial, practice of using cameras to police busy intersections. In this two part series, I’ll let you know what I’ve discovered, but first some history…

For much of the past century, traumatic injuries were considered unpredictable “accidents” rather than a treatable disease processes (like atherosclerosis). Under this paradigm, the root causes of accidents were broken down into three categories: 1) bad luck, 2) the well-deserved result of stupidity, or 3) something arranged by the mafia. Prevention efforts, to the extent they existed, were predicated on warnings such as “Don’t drive too fast and watch out for drunken drivers,” and “Don’t associate with the mafia.” Thus, civilians of the 1960s were duly warned, but not particularly safe. Fortunately, in the mid-1960s, a handful of public health leaders began to transform this concept of “accidents” and in particular motor vehicle “accidents.” Foremost was William Haddon Jr., the seminal director of the National Highway Traffic Safety Administration and the first person to champion the idea that there’s nothing “accidental” about energy transfer resulting in traumatic injury. According to Haddon, it didn’t matter whether the energy transfer came from a high-speed projectile (bullet) or from rapid deceleration in a car crash, the energy transfer’s effects on human anatomy could be studied and modified. Accidents, Haddon argued, and car accidents especially, weren’t unpredictable or random after all and therefore a vehicle hitting a wall shouldn’t be called an accident but rather a crash. Furthermore, the outcome of a crash, in terms of human injury, wasn’t inevitable but instead dependent on key variables such as speed, object malleability and passenger restraint. Haddon attempted to classify and study these variables using a conceptual tool that came to be known as Haddon’s Matrix – a simple 3x3 grid identifying the factors leading to poor outcomes in trauma. One axis of the matrix lists three time periods: “pre-event,” “event,” and “post-event” and the other lists three physical components: “human,” “vector” and “environment.” From his matrix, Haddon extracted ten conceptual strategies for injury prevention – half of which involve the “event” phase of injury and predominantly support “passive” injury protection – protection that is built into existing systems and not dependant on individual compliance. To illustrate, strategy number four recommends “modifying the rate of spatial distribution of the release of the hazard from its source.” This is a long-winded way of saying that an absorbed blow is less destructive, which of course is the concept behind airbags. Strategy number five suggests that we “separate in time or space the hazard being released from the people to be protected,” which simply means that the farther you are from the action the safer you are (e.g. a pedestrian on a sidewalk is less likely to be struck by a car than one on the shoulder).

Today, Haddon’s strategies sound like common sense, but before Haddon, American culture wasn’t hip to prevention. Haddon’s goal was to inspire a paradigm shift, to make prevention groovy – in a long-winded academic way. It worked - nowadays we accept that there are strategies, such as seat belts, air bags and highway speed limits that prevent or limit injury in car crashes. We recognize that crashworthy vehicles save lives and that vehicle occupant fatalities (per mile of travel) decreased by two-thirds between 1964 and 1990. Without a doubt, this is an incredible public health accomplishment, one that has been achieved with very modest impact on personal liberty.

With success like this, it’s not surprising that a whole new generation of pre-event interventions have been proposed to further limit the carnage on our streets before it occurs. One of these is red light camera enforcement, which strives to limit injury and death from intersection collisions. On its face though, red light camera enforcement feels more like Big Brother than airbags or widened shoulders. It also is not passive – it relies on individual citizen’s knowledge, fear and compliance to be effective. This is in contrast to a more automatic strategy, like lengthening yellow light times. So, believe me, when I started looking into this I certainly hoped to discover that the red light strategy does not work. But, it turns out that a recent analysis from the Insurance Institute for Highway Safety (IISH) suggests that it most likely does. There are, however, some serious caveats. Next time, I’ll breakdown the IIHS study and delve into these caveats. In the meantime, does anyone know a good traffic lawyer?