We all are getting older, and so is our brain, which among other tasks, mediates response time and the myriad inputs involved in driving a car. Certainly those with real disabling neurological diseases should not drive, but the vast majority of the Medicare set do not have a medical disorder at all, in spite of the forces that would like to transform the definition of such normal aging to the diagnosis of "Mild Cognitive Impairment."
This is a major social-political issue,
Unfortunately, while it should be, the ongoing medicalization of aging is barely being discussed as such. The ambiguity in both public perception and research of memory decline- changes in terminology and understanding of this most complex organ of cognition, has allowed a social shift to occur without much push back. This article describes how this was embedded in The Affordable Healthcare Act without any discussion at all --and is still mostly unknown.
but this article is more narrow, about how an aging population compounds the damage of the current trends in traffic design that could increase danger for us all. I've focused on two issues relating to this, The first is the ubiquitous four way stop signs, and the second is the trend to roundabouts and various traffic calming devices that are more challenging to drivers, especially older ones.
A car is the most deadly instrument that is controlled by all of us, from the teenager with a brain that has not matured enough to control his/her emotions to the older person who may not have the reflexes to respond to the challenges of driving. Finding the right balance to facilitate this necessity of our daily life while protecting pedestrians and other drivers from tragic accidents is an ongoing problem. Intuition isn't always accurate. Conclusive research (see links below) shows increased unwarranted stop signs actually increase accidents, as the drivers speed up to make up lost time among other causes.
This is no trivial issue as "The National Highway Traffic Safety Administration estimates that distraction and inattention contribute to 20 to 30 percent of reported crashes." With fatalities approaching fifty thousand a year, we dare not allow decisions to be made out of habit or lack of the most serious study. Distraction is not only technology induced, but is caused by political decisions that causes a driver to check for a police car before driving quite safely at a slow speed through an unwarranted four way stop sign.
I recently sent a letter to the members of the Encinitas City Council opposing the removal of a specific traffic light that is slated to be replaced by a roundabout for these very reasons. Last week the New York Times had this article that described exactly what I warned the council of:
"The simple act of turning left ...... is confounded by a traffic circle, where an attempt to head east casts the driver into a ballet of choosing the proper lane, looking for the exit and maintaining a high alert in the crush of beach-seeking vehicles."
Local municipal authorities and traffic engineering departments seem to have adopted a bit too uncritically the worldwide trend to transform cities that grew with the automobile into idealized villages. Roundabouts are in and traffic lights are out. Those roundabouts that are popular usually replace four way stop signs, which are primitive as traffic control but highly effective for politically powerful communities to keep drivers from less august regions from using "their" thoroughfares. The cost in lost time and increased pollution of these signs that defy traffic engineering standards is ignored, or they would be replaced by more effective devices that fit actual traffic patterns.
There are standards published by the Federal Highway Administration that overlay State Laws that can only modify local ordinances. An example of local flexibility is the rule for a complete stop before turning right on a red light. This is similar to the rule for four way stop signs on the lower volume street. In a personal conversation with the traffic director of Riverside California they acknowledge that a full stop is counterproductive, so their camera system excludes any car that slows to 15 mph from getting a summons. This type of rational system could be implemented locally which would improve respect for the laws when they correspond to actual rational prevention of accidents.
We now have little tolerance for those who text while driving, but we have yet to even acknowledge that increased complexity of a given traffic device has the same debilitating effect as answering a cell phone or other distractions. This additional mental effort, most challenging to the increasing numbers of older drivers, may not cause a crash at the site, but increase the stress level of the driver who has an accident down the road, thus defying statistical validation of this effect.
Perhaps some day we will not have to depend on that vulnerable organ the human brain to control the complex and challenging task of driving a car, but until that time arrives driver capacity should be a major part of our approach to traffic safety.
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References:
On Multi way stop signs:
Placing four-way stop signs on roads of very
unequal design, speed and traffic volume will tend
to promote stop-sign violations by drivers, especially
on main roads. Driver expectancies are violated in
situations like this and when this occurs, improper
actionsresult, which can increase safety risk at inter-
sections.
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The mini-roundabout design has been used for decades in Europe, but the
capacity models developed for them may not be applicable to U.S.
settings and drivers. This article provides design recommendations and
an approach to estimate traffic capacity of mini-roundabouts from sites
in the United States.