Joined: Aug 02, 2006
Posts: 705
Location: McLean, VA, USA
Posted:
Wed Oct 25, 2006 11:25 pm
Well, there is no such thing as absolutely safe speed. Nope. None. Nada. Even if your speed is zero, you can still be stricken by meteorite, or a mine can burst under your car, or earthquake can strike, or tsunami can come – pick your choice, or add your own one, the result is the same, regardless. There is no such thing as a safe life for that matter - life’s death rate is 100%! With this in mind, we can try to be more realistic with safe speed definition.
I would call the speed safe, if I estimate the probability of bad things happening on that speed being equal to this of zero speed (see above paragraph) or slightly higher. How much higher depends on personal risk aversion. How good is the estimate depends on personal driving knowledge and experience. That means objective safe speed does not exist. What I deem safe can be considered unsafe by you, and vice versa. Worse, our opinions change as we gain more knowledge and experience.
What to do about that? Accept the fact that driving (and life!) is dangerous by nature and live with that. You can and should try to minimize the risk, but you cannot eliminate risk altogether. And the question of safe speed becomes the subject to risk/reward analysis, as many other things in our life.
Misha you are right. Driving is dangerous and have to be dealt carefully. Even though If we are carefull enough to drive safely, its not in our hands that we meet with an accident when other car driver hits us. Its unavoidable case.
Well, there is no such thing as absolutely safe speed. Nope. None. Nada. Even if your speed is zero, you can still be stricken by meteorite, or a mine can burst under your car, or earthquake can strike, or tsunami can come – pick your choice, or add your own one, the result is the same, regardless. There is no such thing as a safe life for that matter - life’s death rate is 100%! With this in mind, we can try to be more realistic with safe speed definition.
I would call the speed safe, if I estimate the probability of bad things happening on that speed being equal to this of zero speed (see above paragraph) or slightly higher. How much higher depends on personal risk aversion. How good is the estimate depends on personal driving knowledge and experience. That means objective safe speed does not exist. What I deem safe can be considered unsafe by you, and vice versa. Worse, our opinions change as we gain more knowledge and experience.
What to do about that? Accept the fact that driving (and life!) is dangerous by nature and live with that. You can and should try to minimize the risk, but you cannot eliminate risk altogether. And the question of safe speed becomes the subject to risk/reward analysis, as many other things in our life.
lol...you know, that's about the best definition of safe speed ever! I actually learnt it word to word and repeated it my hubby the other day we were driving! you should have seen his face! (most impressed, I could tell!). Let's hope the cops have a similar outlook..... !
But there is a certain speed or range of speed which will be suitable to the conditions and that's the speed we need be driving in. Not few are the countries (including my own) where sometimes the speed limits on highways is lower than the speed which suits the conditions!
Joined: Aug 02, 2006
Posts: 705
Location: McLean, VA, USA
Posted:
Wed Jun 13, 2012 6:50 am
Astraist wrote:
But there is a certain speed or range of speed which will be suitable to the conditions and that's the speed we need be driving in. Not few are the countries (including my own) where sometimes the speed limits on highways is lower than the speed which suits the conditions!
Yep Astraist, most governments tend to be over-restrictive with highway speed limits. At the same time, smaller roads often get unpropotionally high speed limits, at least here in the USA. Like I often see 45 mph or even 55 mph limits on two-lane narrow winding roads on Virginia countryside, and multilane highways around DC have 55 mph limits across the board. Does not make any sense from a safety standpoint, yet makes it much more convenient for government to rob the citizens with speed fines.
Safe speed should be slightly under your skill level, equipment capability, and road conditions. I recently reached "Official Geezerdom", 60 y/o. For the last 10 years I have limited myself to driving no more than 8/10ths. I will now reduce that to 7/10ths. That still puts me ahead of most of the "steerers" as opposed to actual drivers. I remember reading a study of "drivers" tolerance (when they became uncomfortable) of lateral "G" force. The average was .27 "G"! I don't think I could feel .27 "G" of lateral accelleration!!! The worst handling vehicles sold in the U.S. are capable of .75 "G"! A couple of years ago I ended up behind a brand new BMW 128i. on one of my favourite twisty roads. I thought "cool" I can see what this new Beemer can do. What a disappointment. It slowed to less than 10mph on curves that a hummer could take at 50mph! When we arrived at the stop sign at the bottom of the hill I could see the "driver" was a teenage girl in her highschool graduation present. What a waste. My biggest problem with excessive speed is residential streets. I have seen vehicles speeding up to 50mph in a 25mph zone. There are children playing in these speed zones! I am very sensitive to this. In 1973 I was going between 25 or 30 mph on a residential street. A 4 y/o boy ran into the street from between parked cars. I locked the brakes but still punted him about 40 feet. Fortunately he survived with a broken arm and major road rash. I tend to drive less than 25mph on residential streets since that accident.
Safe speed should be slightly under your skill level, equipment capability, and road conditions. I recently reached "Official Geezerdom", 60 y/o. For the last 10 years I have limited myself to driving no more than 8/10ths. I will now reduce that to 7/10ths. That still puts me ahead of most of the "steerers" as opposed to actual drivers. I remember reading a study of "drivers" tolerance (when they became uncomfortable) of lateral "G" force. The average was .27 "G"! I don't think I could feel .27 "G" of lateral accelleration!!! The worst handling vehicles sold in the U.S. are capable of .75 "G"! A couple of years ago I ended up behind a brand new BMW 128i. on one of my favourite twisty roads. I thought "cool" I can see what this new Beemer can do. What a disappointment. It slowed to less than 10mph on curves that a hummer could take at 50mph! When we arrived at the stop sign at the bottom of the hill I could see the "driver" was a teenage girl in her highschool graduation present. What a waste. My biggest problem with excessive speed is residential streets. I have seen vehicles speeding up to 50mph in a 25mph zone. There are children playing in these speed zones! I am very sensitive to this. In 1973 I was going between 25 or 30 mph on a residential street. A 4 y/o boy ran into the street from between parked cars. I locked the brakes but still punted him about 40 feet. Fortunately he survived with a broken arm and major road rash. I tend to drive less than 25mph on residential streets since that accident.
I completely agree with you. I have a small child myself and one of my pet peeves in speeding cars in residential streets! I walk my daughter to a nearby park and we often have to cross streets in front of houses to reach it. it's a nightmare to suddenly have a car rush at you, I can tell you that.
Safe speed should be slightly under your skill level, equipment capability, and road conditions. For the last 10 years I have limited myself to driving no more than 8/10ths. I will now reduce that to 7/10ths. That still puts me ahead of most of the "steerers" as opposed to actual drivers.
7/10ths is good for track days - but it does not offer the necessary safety margins on normal roads. I would consider 6/10ths as the most high limit of performance for road driving.
sgtrock21 wrote:
I remember reading a study of "drivers" tolerance (when they became uncomfortable) of lateral "G" force. The average was .27 "G"! I don't think I could feel .27 "G" of lateral accelleration!!! The worst handling vehicles sold in the U.S. are capable of .75 "G"! !
Handling has nothing to do with the G-force you can experience. G-forces are all up to the grip the car can generate and how much it's chasis can withstand and last but not least - how aerodynamic it is. A car could never exceed one G unless it has somekind of aerodynamic assistance.
sgtrock21 wrote:
My biggest problem with excessive speed is residential streets. I have seen vehicles speeding up to 50mph in a 25mph zone. There are children playing in these speed zones! I am very sensitive to this. In 1973 I was going between 25 or 30 mph on a residential street. A 4 y/o boy ran into the street from between parked cars. I locked the brakes but still punted him about 40 feet. Fortunately he survived with a broken arm and major road rash. I tend to drive less than 25mph on residential streets since that accident.
Excessive speed relative to the road conditions (And driver, and car and etcetra) is a problem everywhere: In residential streets, in main city roads, in single-carriageways and in highways.
Even an open highway does not justify driving at speeds such as 100mph or more. In particular, many highways don't have the necessary conditions the be considered motorways or autostrades - like wide shoulders, special guardrails, open curves and protection against animals entering the road - so they require even slower speeds.
Joined: Aug 02, 2006
Posts: 705
Location: McLean, VA, USA
Posted:
Wed Jul 18, 2012 7:11 pm
Astraist wrote:
Excessive speed relative to the road conditions (And driver, and car and etcetra) is a problem everywhere: In residential streets, in main city roads, in single-carriageways and in highways.
Even an open highway does not justify driving at speeds such as 100mph or more. In particular, many highways don't have the necessary conditions the be considered motorways or autostrades - like wide shoulders, special guardrails, open curves and protection against animals entering the road - so they require even slower speeds.
Excessive speed is certainly a problem everywhere, yet on residential lanes it is greatly exacerbated by the fact that speed numbers per se are not too high, yet can bring much more trouble than much higher numbers on a highway. People just don't realize the relativity of safe speed.
Like " I am driving only 40 mph, it's a low speed, what is the problem with it?". Yes, it is low and there is no problem when you do it on a wide multilane road. But for a narrow residential lane with no room for maneuver and very limited visibility because of parked cars, that speed is way excessive and will get you in trouble.
As for 100 mph on highways - I would say the vast majority of American interstates and cars qualify for speeds of 100 mph and more - providing a driver can handle it. However, the prevailing speed limit is 55, 65 at best, and driving above 100 will automatically land you in jail in most states (don't ask me how I know )
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