Speed detection is one of the most notorious functions of our local and state police. How do they know how fast we are going? Speed determination is accomplished in two basic ways. First, the least sophisticated method is dependent upon an officer's ability to guess your speed. Second, either some electronic method using radar or laser instrumentation authenticates that officer's guess. As you will see, their guesses are usually right on target.
What does this mean for you? Usually a speeding ticket or if your infraction isn't a flagrant disregard for safety, a friendly warning.
Speed(s) is the distance travelled divided by the total time it took to get from the starting point to the ending point, or:
s=(Dx)/(Dt)
How does the speedometer work?
Your vehicle's speedometer determines your speed by examining the angular velocity(v) of your axle (how fast your axle spins) and multiplying it with the manufacturers' recommended circumference for the vehicle's tires. (This is why using oversize tires will cause your speedometer to register a lower speed than your actual travelling speed-the circumference of the oversize tires is greater than that of the recommended tires, while the angular speed remains the same) So, in application:
s = v*2pr
Why should we limit our speed?
Speed limits are designated for roads based on the roads characteristics such as its geometry and capacity, and traffic characteristics such as overall volume, hourly volume and traffic density. Speed limits are designed to most effectively and safely regulate traffic.
There are several methods of manual speed detection, but they are all based on obtaining a known distance and comparing it to the time it took to travel that distance. Officers who have been watching traffic for a long time tend to get a really good grasp of almost instantaneously knowing how fast vehicles are travelling. A table showing an officer's guess along side an inexperienced observer's guesses and the radar results is shown below. Note that Officer Keeler's guesses are all within 3 mph of the actual speed. My guesses tend to have a higher deviation and were sometimes influenced by officer Keeler's guesses if he spoke first.
The other methods include using a stopwatch and timing a vehicle on a known distance, either from the ground or in an aircraft, and pacing a vehicle. Pacing a vehicle involves either matching speeds with the vehicle and checking your speedometer or locating distinct markings and counting so that you can again divide distance by time to obtain a speed.
This study was created by Lt. Wells on behalf of the Florida Highway Patrol. Lt. Wells was a member of the Law Enforcement Stops and Safety Subcommittee. This committee is volunteer-based and works under the financial support of the National Highway Traffic Safety Administration and is affiliated with the International Association of Chiefs of Police. As a me...
Our project required our car to go at least 3 meters. Our initial trials were successful because our car went 7,8, and then 9 meters. The car went 7 meters in 8 seconds with a speed of 0.875 m/s. It went 8 meters in 10 seconds with a speed of 0.8 m/s. It finally went 9 meters in 12
“We will catch you and there will be consequences, criminal consequences, loss of licenses and even a jail term,” Col. Thomas Robbins, Massachusetts State Police warned aggressive drivers at the launch of ‘Road Respect’, a Spring Mobilization program at the Newton Police headquarters on the morning of April 4.
Drivers who speed often do not realize the enormous danger they are creating. When someone is speeding they have a higher braking time and are often going too fast to notice all of their surroundings, and fail to take all of the safety precautions a driver should use. Road conditions play a large role in the effects of speeding. Choosing to speed can also get a person’s license taken away, cost a fortune, or both.
8.) Great Britain. Department for Transport. London. Relationship between Speed and Risk of Fatal Injury: Pedestrians and Car Occupants. By Richards. Transport Research Laboratory, Sept. 2010. Web. .
Sorensen, Karen. "Speed Warning Signs No Deterrent for 95 Drivers." Plainfield Patch. 23 Oct. 2011. Web. 02 Nov. 2014.
drivers travelling at high speeds on roads (Hartman). To conserve fuel and save lives, the
...bit faster than normal. What should drivers do? Well, there is something we can do that would allow for us to be able to raise the speed limits. We can write to our local representatives and let them know the need for raising the speed limits. Provide good research and valuable information that will help them to make the best possible decision. Of course, we must obey the law until the speed limits are changed. God has commanded us to render unto Caesar what is Caesar’s. (Bible) This was used not only in the aspect of money but also in the aspect of all of Caesar’s laws. The urge is very real to want to break the law, but think about others before yourself. According to Terry Turner we need to think of the why before the how. Basically ask yourself, why do I need to speed? Then after careful consideration of all factors, decide how fast to drive your automobile.
Moreover, not only did I not comply with the speed limit, I did not obey my
Should highway speed limits be increased? Should we strike down every sign that the government posts and uses to regulate the speed limit on the thousands of highways around the country? Should we trust the driving ability of each and every person to drive within a reasonably safe speed? The response that most people lean toward is one of negativity. People automatically assume that the speeds presently posted on our highways are there only for our own protection.
In our text we began our study of physics with motion because motion is a dominant characteristic of the Universe (Kirkpatrick, 21). In class we learned that speed is the distance traveled divided by the time taken, s=d/t. The definition of velocity is very close to that of speed except that direction of an object is also taken into account.
1.3.b. Rate of flow: The equivalent hourly rate at which vehicles pass over a given point or section of a lane or roadway during a time interval less than 1hr. usually 15 min.
According to Federal Highway Administration (FHwA) study in which speed limits were varied at 100 locations nationwide resulted "raising posted speed limits by as much as 15mph had little effect on the motorists' speed." The data actually indicates that accident rate reduced at sites where speed limits were raised. Traveling at high speeds saves time and gets you to your destination quicker and the traffic usually travels five to ten miles faster than the posted speed limit.
Imagine driving on I-75 as cars race by you at a blink of an eye. You are driving 60 miles per hour, the speed limit; they must be doing 100 miles per hour or more. This is not an illusion; this is the reality of driving on a highway. Believe it, it happens everyday. Cars race down the road at uncontrollable speeds that cause tickets, accidents, and sadly death. Speed limits are a must for traffic control, for safety in neighborhoods and for avoidance of collisions.
It is important to follow all traffic laws to keep everyone safe on road. The amount of traffic accidents and losses drops significantly when people are obeying the rules on the road. Sometimes we forget what a big responsibility it is to drive carefully. Traffic laws are designed to protect you and other drivers on the streets. If we don’t follow them we are not only putting ourselves in risk but also other innocent people. By knowing the rules of the road, practicing good driving skills, you help play a vital role in preventing a crash. You will also be making the safety policies more effective. Many components play a major role in road safety including speed limits that are posted and making sure safety equipment is properly installed and used.