The designing of roads and road-furniture (bizarre phrase, but there you go) to discourage cars from speeding. The most common type of traffic calming device is the speed bump, or sleeping policeman (that's has to be a UK only phrase...), but twenty miles an hour signs, speed cameras, road narrowing and huge chevrons painted on roads are also used.

The phrase 'traffic calming', though, is naively hypallactic - and probably consciously so, too, suggesting that it's not the car drivers who are angry, or indeed speeding, but just the cars on their own regardless of the no doubt sober minded, rational driver. Bad cars - naughty cars. The upshot of all this, of course, is an implicit suggestion that car drivers are innocent.

So, 'they' reason, let us calm these aggressive, bad-tempered and strong willed cars with bumps and ramps, automatic fines, traffic lights and roundabouts... Cars may now be calm: the drivers, though, are anything but. It shouldn't be called 'traffic calming' - it should be called 'driver annoying'. Those people who stuck to the speed limit before the measures were taken invariably still drive conscientiously. And those who didn't, warranting the measures in the first place, use speed bumps to take off from, narrow roads to justify their mounting of the pavements, and traffic lights rather like those F1 race-car drivers use the lights system at the beginning of grand prix.

Leading to 'resident annoying'. I wonder how we could calm them?

Another 'traffic calming' measure found here in Ottawa, Canada is zig-zagging lane configurations, forcing drivers to swerve left and right when entering or exiting intersections. This becomes dangerous when the pavement is covered in snow. The locals, used to the funky arrangement, will swerve, much to the panic of out-of-towners wondering why the fsck is this guy is driving into his lane.

It should be noted that emergency vehicles are also affected by such measures, so in reality, someone somewhere may die because an ambulance could not reach him in time.

Traffic calming, according to the Institute of Traffic Engineers (ITE) "involves changes in street alignment, installation of barriers, and other physical measures to reduce traffic speeds and/or cut-through volumes, in the interest of street safety, livability, and other public purposes." Traffic calming measures fall into two broad categories of volume control and speed control. Volume control is principally used in residential areas to reduce the number of vehicles that will take shortcuts through the area, speed control is used on major thoroughfares to reduce the speed. In addition to engineering efforts, traffic calming can be the result of enforcement and education.

The goal of traffic calming is to treat traffic as a fluid, much like a raging river. The individual vehicles and drivers may be annoyed, but the flow is made less turbulent.

The types of calming measures*:

Volume Control

Full Closure
Barriers placed across a street to block vehicular traffic. see also: cul-de-sac, dead end
Half Closure
A barrier at an intersection to prevent traffic from entering a two-way street.
Diagonal Diverter
Barriers placed diagonally across an intersection, Preventing through traffic.
Median Barrier
Islands that extend through an intersection, preventing left turns to or from side streets.
Forced Turn Island
Islands at an intersection that force traffic to make a right turn, usually when a cross street enters major road.

Speed Control Measures

Speed Hump
A rounded, raised area, usually between 3 and 8 meters across.
Speed Table
A flat-topped speed hump, usually with a trapezoidal cross-section.
Raised Crosswalk
A speed table which is marked as a crosswalk. This has the added benefit of making pedestrians more visible.
Raised Intersection
An entire intersection which has been elevated as a speed table, with ramps on all approaches
Textured Pavement
Using a textured material such as brick or cobble, which is not only aesthetically pleasing, but uncomfortable to drive over at high speed
Traffic Circle
Islands placed in the middle of an intersection, which requires traffic to curve around.
Larger versions of traffic circle, also called a rotary.
Curb extensions, islands, or side-to-side alternating parking patterns which force drivers to travel in an S-shaped path, rather than in a straight line.
Realigned Intersection
Intersections that change T-intersections into more curved Y-shaped intersections.
Curb extensions at intersections to reduce the number of lanes.
Center Island
Street narrowers that remove a chunk from the middle.
Street narrowers that remove chunks from the sides.
*All left and right-handedness terms are for those who drive on the right side of the road. Reverse the terms if you drive on the left side.


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