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Joined: May 03, 2011
Posts: 24
Location: USA

PostPosted: Thu May 19, 2011 12:55 am Reply with quote Back to top

Road fatalities have turned into one of the biggest 'killers' in modern society. One of the biggest reasons for road mishaps is 'speed'. So, the simplest solution is to slow down speed. The speed associated limitations are imposed on drivers for safety concerns. So, it is their duty to pay attention to speed signs and even restrict the speed to ten k/h under what sign says.

1. The basic rule is to 'slow down' to take corner successfully. Weather condition is another area that you need to give special attention.

2. Alcohol is another major reason for road mishaps. It is human nature to believe that they know what they are doing, particularly when they are drinking.

3. A simple rule to keep in mind for driving safely is common civility. If one allows others to go ahead, one can save various probable troubles on the road from happening.
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Joined: Mar 27, 2010
Posts: 209

PostPosted: Thu May 19, 2011 4:35 am Reply with quote Back to top

You brought up a problematic issue amongst driving enthusiasts and this is the subject of speed. The question of whether speed kills or not is a hot debate between institutional parties and driving enthusiasts, which revolves in part around semantics. It is especially profound in my homeland, where the speed limits on certain highways are rediculously slow relative to the speed which the conditions allow, and police officers find it much more comfortable to enforce those speed limits on straight, wide and open stretches of highway and not enforce speeding or other offences in areas that are more relevant for reducing the rate of collisions.

If to refer to the subject of whether speed kills than the basic answer is YES. If there were no moving cars around, there were no collisions. Likewise, it is plausible to assume that an increase of speed limits increases the amount of collision per given road section, and magnifies the bad outcomes of those collisions.

One of the main points against speed enforcement is that, according to all western statistics, speeding is related to only 4%-8% of the collisions. This is a mantra very widely used in my country, but it stands in contradiction because the same people who citate this data, give no credibility to the authorities that derived it. In most countries, the police inspects the collisions based more heavily on criminal law than on driving and physics. If they would have inspected collisions more carefully, the statistics would show one of two results:

- No speed-related collsions. Because speed by itself cannot be the direct cause of the collision. Think about a highway with the limit of 60mph. How on earth can a situation come to pass, where the very act of accelerating to a speed of 65 would instantly and directly result in a crash?

- The other result occurs when you think of speed as one of the contributing factors. This is actually true to all kinds of crashes. They never occur based on a single problem (otherwise there would have much more collisions), but rather on a combination of such factors. IF we consider all situations where speed was a contributing factor, the statistics would swell up to about 15%!

To have claimed that speed is merely an indirect cause of a collision does not reduce it's acute contribution to collisions. It's like sliding on an icy corner. You can never slide because of the ice. You will slide because of too much speed/steering/braking/acceleration. The ice is merely a contributing factor. But it's clear that, even as a contributing factor, it has the most vital effect on the outcome (which is a collision). The same can happen with speed.

This happens when the speed does not match the conditions. If the speed is too high or too low, it will increase the risk level. Driving too slow relative to the conditions, makes the driving time longer (hence increasing the exposure to hazards), makes the driver less attentive and might interfere with the flow of traffic. Speed limits should reflect a certain situation (usually when the traffic on the specific road section is very light) where the speed on the sign is roughly equall to the proper speed relative to the conditions. However:

- There are highways where, assuming light traffic, an attentive driver and a good car, the speed limit might be too low.

- There might be side-roads/streets near schools/dense traffic where the speed limit is too high.

- Adjusting your driving speed relative to the condition is constant. You always constnatly change your speed to match the chnaging conditions. The speed on the speed limit is more of a "rule of thumb." Of course the proper speed relative to the conditions is not a fixed number, it's a certain range of speeds which changes from driver to driver (when driving on the same road at the same time).

Specific problems and collisions related directly or indirectly to speed can include: Speeding relative to the conditions, mainly in urban areas, where we have lots of "variables" and hazards to anticipate and deal with. At speed, the ability to anticipate every necessary change of speed/position in time is reduced and we cannot "soak it all in" in time. In Israel, I see many people roam in towns at speeds of 70km/h (instead of the 50km/h limit). Most local advanced driving courses illustrate how this increases the overall stopping distance (with the reaction time included) by more than twice (!), making it impossible to react to things in the short ranges that are so typical in urban driving.

Speeding can also be too much or too little relative to the traffic flow. This hinders our ability to maintain a safe following distance from cars ahead and behind. The result is tailgating and constant lane changes, and a great potential for crashes that, when they occur, are often labeled under "swerving from the lane of driving" but are in fact speed-related crashes. I this case and the above case, speeding does not even shorten the arrival time!

Speeding is particularly hazardous in winding roads, where speed is a great factor in the ability to control a car as it turns. If you remember the formula for maximum cornering speed -- mv²/r = mgμ -- than you can clearly see that the effect of speed (v) is much greater than the effect of the turning radius (r), grip levels (μ) or load/weight transfer (m), because it increases squarelly.

In fact, all forces working on the car increase squarely with the increase of speed. Tire wear is doubled, gas milleage (along with wear to the drivetrain and pollution of the atmosphere) is increased dramatically at around 120km/h and higher, and the suspension also has a hard time. Most road tires on road cars don't have that high a speed rating. If we take an average Q-rated tire, which can drive at a speed of 160km/h under full load and with full inflation, we can assume that it would be possible to drive the car to about that speed, with normal load and inflation, for about an hour without causing to much of a damage to the tire.

However, let's assume a very reasonable case where the car (and hence both it's tires and dampers) did about 60,000km, which considerably wears it, and that the tires are two years old, slightly under inflated and the car is partially loaded (even two adult passengers can face an additional load to the tire), than -- on a hot sunny day, the tire can be in a serious hazard of a blowout in long highway drives at a high speed. Such blow-outs are hazardous due to the possiblity of a pursuant lost of control, or a forced stop alongside the road in a dangerous location.

Another possible situation is when the road is wet, where tires, even new tires with their full tread depth, can have a trouble in channeling all of the water through (the amount of water to channel per second at 60 is one gallon) and begins to hydroplane. A 2mm deep layer of water can turn into something slippety like a spill or diesel on the road.
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Joined: May 02, 2011
Posts: 24
Location: USA

PostPosted: Mon May 23, 2011 4:01 am Reply with quote Back to top

Great information dude........! I am really impress from your post. Thanks for sharing with us.
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