Quote:
Originally Posted by Bedford_DJ
Don't get me wrong guys I'm all for a walkable, livable city but one still has to remember that there will always be a requirement for roads in town and the best way to streamline traffic while keeping neighbourhoods livable is to get the traffic onto one road and off the side streets until such a time that roads can be closed to traffic.
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That idea has been the planning orthodoxy for more than sixty years. If you look at most suburban areas this is exactly how roads are layed out - local roads feeding into collectors, feeding into arterials, sometimes feeding into highways. It's actually a poor way to look at things. Traffic is an exceptionally complex system. Thousands of individuals, with many potential routes, make thousands of individual decisions. With a hiearchical road structure you discourage or remove many of those potential routes in favour of fewer routes with heavier traffic, and generally higher speeds. You remove a lot of complexity from the system, believing that the simplified "streamlined" system is obviously going to work better than the chaotic traffic patterns you replaced. The opposite happens because you've taking a huge amount of traffic from many different roads and placed it on a couple. Equally important you've removed the option of taking alternative routes when one arterial becomes congested. Instead of choosing between many potential routes with moderate congestion there are simply a couple of routes with heavy traffic.
A lot of the justification for this road structure comes from the idea of removing cars and traffic from local, residential streets. It comes from a deeply ingrained idea that the automobile is a dangerous beast that's unfit for many parts of our cities - a position that almost everyone on this board seems to hold in some shape or form. Some feel that since the automobile and taffic are a nuissance and potentially dangerous we should restrict the bulk of traffic to properly designed arterials and increase capacity when we need to. This may improve traffic flow in one small part of the system, at the expense of the "livability" of one or two particular streets, but that's the price we pay to move cars, which is clearly a necessity. Most other arguments fit into some form of cars and traffic are inherently bad for cities, and most things we do to accomodate them are therefore bad. Hence the "anti-car" argument.
The idea that the automobile is evil isn't true. The automobile is not ruining our cities. Certain byproducts of how we plan and accomodate cars are the problem - oversized parking lots, high speed arterials, congestion, air pollution and smog, etc. Some may argue these things are a necessary evil, but I doubt many would argue these things are good for our cities. The problem is not that we have cars in our cities but that too much emphasis has been placed on moving cars efficiently, generally at the expense of other forms of transportation, or livability and urbanism.
In the end the debate usually comes down to whether to widen a congested arterial, and a fight breaks out between the two camps. Shouldn't the first question be "can we provide alternative routes or alternative transportation modes to relieve this congestion?" Most cities streets carry hardly any traffic, and this is a deliberate choice. We've made this choice because we hold the simplistic belief that cars are unsuitable for most streets. This is partly true - the way traffic moves on high speed arterials is unsuitable for most streets, including some of those arterials. But we've deliberatly designed arterials to work that way in the first place. Local roads could carry an increased proportion of the traffic, at lower speeds, reducing the need for road widenings and the disruption they cause. We have to move past this belief that anything but local traffic is 1) something unsutaible for most streets and 2) something that is fixed by "streamlining" the street system or adding a lot of capacity in select parts of a very complex system.