04-15-2010, 10:54 AM #1
Highway 98 gold mine for Walton County
Does any one know if only a three second yellow light is allowed by the State on a highway with a speed limit of 45-65 MPH? I hope the intersections between Grand Blvd and 30A are not targeted by Walton County Police because of the very short 3 second yellow lights. In average traffic with everyone moving at 55 MPH it is not possible to stop it the light turns yellow when you are still 50 feet before the intersection. If you choose not to stop short and get rear ended, you will not make it fully through the entire intersection before light turns red.
Cities Shortening Yellow Traffic Lights for Deadly Profit | Civil Liberties | AlterNet
The other thing is the 45, then 65, then 55, then 45 MPH speed limit. If you blink you wont know what the speed limit has changed to as you go down 98. Why cant we just make it all 45 MPH? This trick affects the tourist the most who have never seen such a crazy thing.
If the County truly cares about safety we need to lengthen those yellow lights to a full 6 seconds and change the speed limit on HWY 98 to 45 MPH the entire way through Walton County. The Police will have to look for another source of revenue. Perhaps a ticket not washing your car.
An attentive driver going the speed limit can easily stop if they need to.
Contrary to popular belief, yellow does NOT mean "accelerate to make the light."
The Following User Says Thank You to scooterbug44 For This Useful Post:
04-15-2010, 11:14 AM #3
The Red Light Running Crisis
Is it Intentional?
Office of the Majority Leader
U.S. House of Representatives
5. Changes in the Safety Codes
1. Something Funny
2. Camera Revenue
3. The Theory
4. The Fact
5. Code Changes
6. Cameras Ineffective
(200k, PDF format)
View the Documents
Where do the problem intersections come from? We've seen that experience tells us that if there's a red light running problem, yellow light times should be increased. And the theory tells us the same. So why have yellow signal times decreased? The answer is that the organizations responsible for maintaining our intersection safety codes have altered the regulations specifically to accommodate camera enforcement and decrease yellow times.
30' 50' 70' 90' 110'
20 3.8 4.4 5.6 5.7 6.4
30 3.6 4.1 4.5 5.0 5.5
40 3.9 4.2 4.5 4.9 5.2
50 4.1 4.4 4.7 5.0 5.2
60 4.5 4.7 4.9 5.1 5.4
Source: 1976 Transportation & Traffic Engineering Handbook The chart below provides the theoretical minimum yellow clearance signal times based on speed and intersection width from the 1976 edition of the Institute of Transportation Engineers (ITE) handbook. Note that the 100-foot intersection in Beaverton, Oregon had a 3.1 second yellow signal time in a 30MPH zone, as mentioned in Chapter 1 above. As one can see from the chart, that time would be inadequate for any condition. But it's quite profitable for the red light camera installed at that location.
To understand more fully the extent of changes to the signal timing codes, one must first examine the prior formula used for calculating yellow times.
The 1976 ITE Handbook
In 1976, yellow time was known as the "yellow clearance interval." This was the theoretical minimum amount of time needed for an automobile to clear the far side of the intersection from a given distance away, or come to a safe stop. This was calculated by adding three variables:
Reaction time: How long it takes, on average, to recognize the situation and decide whether to stop or continue through the intersection. Usually this is 1.0 seconds.
Stopping time: This figure is calculated based upon the length of the intersection and the average deceleration rate for automobiles.
Time needed to clear the intersection: Based on the approach speed, how long it would take an automobile to traverse the length of the intersection.
The 1985 ITE Proposed Recommended Practice
By 1985, ITE had begun to change the way signal times were calculated in the past. The first modifications were published in their "Proposed Recommended Practice" a mere three years after New York City began researching how it would implement the first red light cameras in the United States.
These changes were further explained in the 1989 ITE Journal article, "Determining Vehicle Signal Change Intervals." This report begins by clearly stating that the ITE's intent is to change laws across the country because, "adopting a uniform method cannot precede adoption of uniform laws" (page 27). In other words, for red light cameras to be adopted nationwide, the laws must change nationwide. And they provide at least three methods that have as their result a reduction, in most cases, of yellow signal time as well as easy adoption of camera enforcement.
1. Their goals are not entirely safety related
The goals and objectives of the 1985 and 1989 documents are clearly related to red light camera enforcement. Consider:
Goal: Recommend legal definitions for the various aspects of the change interval and a defensible methodology for calculating and evaluating change intervals. (1985, page 5; 1989 page 27.)
And the second signal timing objective listed:
Allow easy identification of violators by law enforcement agents. (1985, page 5; 1989, page 28.)
This is a strange goal for someone who wants to design safer intersections. Yet it is a perfect goal for one whose true intent is not safety but rather the convenient installation of a red light camera.
2. Reduced Yellow I: Ignore the Actual Speed of Traffic
The first method for reducing yellow time is found on page 29 (1989) where the document states, "It may be possible to use the posted speed as the approach speed."
What that means is that signal times would be determined by the speed limit rather than the actual speed 85 percent of traffic is traveling, known as the "85th percentile speed." The result of this change in practice would be an underestimate of the actual speed of vehicles at the intersection. And this factor alone can result in yellow time shortfalls of 20 percent or more.
The laws of physics dictate that the distance required to stop your car is based entirely on the speed at which you are traveling, not what is printed on a sign on the side of the road. No rational safety consideration would lead one to choose posted speed over actual speed. But it does allow for a reduction in yellow light time.
3. Reduced Yellow II: Replace yellow time with "all-red clearance"
A comparison of old and new calculations
1976 & earlier Yellow time:
The result: Reaction time + Stopping time + Clearance time
Included in yellow time, plus all-red of 1-2 seconds at the option of the engineer.
Entries on red happen, but are rare.
1982-1985 Yellow time:
The result: Reaction time + Stopping time
Has changed from yellow to all-red.
Yellow is reduced by a third from '76 values, and more red entries occur.
1999-present Yellow time:
The result: Reaction time + Stopping time
All-red clearance time is now optional.
Yellow time is the same as '85, but opposing traffic gets the green while people going the other way are entering and clearing the intersection against their own red signal.
Take the traditional definition and formula for calculating the duration of the yellow light signal. You might need three seconds of yellow to warn approaching motorists that they need to stop, and two more seconds of yellow on top of that to allow vehicles enough time to clear before opposing traffic is given the green light. The total yellow time for such an intersection would be five seconds.
On page 30 of the 1989 report, the ITE proposes to take that five seconds of yellow in the hypothetical intersection above and reduce it to three seconds of yellow, and two seconds in which all sides of the intersection are given the red light (this is known as the "all-red period"). Eliminating that much yellow time, again, is of questionable safety value. But there is no question that in practice this method would yield an increase in the number of vehicles that enter the intersection on red, given the two second reduction in the amount of time one would have to clear the intersection legally. Again, it is unlikely that a rational safety consideration would lead you to choose this method. But it does allow for a reduction in yellow light time. And it will increase red light running. Why? Because the light turns red faster.
Changes were made to the code specifically for camera enforcement
These changes are significant. But if it was not clear enough in the above documents that ITE had cameras in mind in 1985, they make it explicit a few years later. The 1994 ITE "Determining Vehicle Signal Change and Clearance Interval" states:
When the percentage of vehicles that entered on a red indication exceeds that which is locally acceptable, the yellow change interval may be lengthened (or shortened) until the percentage conforms to local standards, or enforcement can be used instead. (Page 5, emphasis added).
In other words, if too many people are running red lights, jurisdictions need not address deficiencies in intersection design or signal timing. Instead, they can simply "use enforcement" by putting up a red light camera. They are suggesting creation of an intersection that will have a perpetually high level of red light runners by design. Since enforcement by police officers wouldn't be 24-hours a day, it is hard to conceive that they had anything other than 24-hour red light cameras in mind.
Changes in the yellow light formula linked to red light running
Yellow Times Compared
Posted speed: 35 MPH. Width: 80 feet. Grade: 2.6% downhill.
1976 ITE Formula 1999 ITE Formula
(round up to 5) 3.8 seconds
(round up to 4)
The changes in the yellow signal timing regulations have resulted in the inadequate yellow times. And these inadequate yellow times are the likely cause of almost 80 percent of red light entries, as discussed above.
If we look closely at one of the intersections Retting studied, the signal at Columbia Pike at Greenbrier in Arlington, Virginia, we find that it has a measured yellow time of 4.0 seconds. This location was the second site studied in his "Red Light Running and Sensible Countermeasures." Using the 1999 formula results in a one second (20 percent) decrease in the yellow time compared to the 1976 formula. And, as mentioned above, according to Retting's study, 77 percent of red light entries happened in that first second the light was red instead of yellow.
Thus, if the old formula had been employed, the red light entry problem Retting studied would have been substantially reduced.
Elimination of the vehicle change interval, a chronology
It may be useful to consider the following excerpts from signal timing regulations that, when presented in chronological order, show a clear progression toward lowering yellow times to accommodate red light cameras:
1985 -- ITE, "Determining Vehicle Change Intervals: A Proposed Recommended Practice," states, "When the percent of vehicles that are last through the intersection which enter on red exceeds that which is locally acceptable (many agencies use a value of one to three percent), the yellow interval should be lengthened until the percentage conforms to local standards."
1988 -- Federal Highway Administration, "Manual on Traffic Control Devices" (MUTCD) states, "Signal Operation Must Relate To Traffic Flow" (Section 4B-20). Note that red light camera promoters use the opposite principle: they wish to use signals to modify traffic flow.
1994 -- ITE, "Determining Vehicle Signal Change and Clearance Intervals" states, "When the percentage of vehicles that enter on a red indication exceeds that which is locally acceptable, the yellow change interval may be lengthened (or shortened) until the percentage conforms to local standards, or enforcement can be used instead."
1999 -- ITE, "Traffic Engineering Handbook: Fifth Edition" states, "The red clearance interval is an optional interval that follows a Yellow Change Interval and precedes the next conflicting green interval. The red clearance interval is used to provide additional time following the Yellow Change Interval before conflicting traffic is released" (page 482).
2000/2001 -- Federal Highway Administration, "Manual on Traffic Control Devices" (MUTCD) states, "47. Red Clearance Interval: an optional interval that follows a yellow change interval and precedes the next conflicting green interval" (page 4A-5, Part 4, Highway Traffic Signals). Yellow time is calculated from "E. The posted speed or statutory speed limit or the 85th percentile speed on the uncontrolled approaches to the intersection" (page 4C-3).
In all the above citations, emphasis is added to the key changes. The words in italics mark the differences between the old and new codes. Namely:
The "should" in 1985 was changed to "may" in 1994.
"Or shortened" was added to the formulation in 1994.
"Or enforcement can be used instead" was added in 1994.
"Optional" was added to the definition of red clearance interval in 1999.
Finally, the Federal Highway Administration endorses all these changes in the December 2000 edition of the MUTCD.
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Not an engineer, just a regular driver and observer.
And I don't think it is a revenue scam as the one time I totally deserved a ticket for running a light I only got a warning and lecture.
04-15-2010, 12:14 PM #5
- Join Date
- Dec 2005
a link would have been sufficient.click >> Filter your water instead of using bottled water << click
04-15-2010, 01:36 PM #6
04-15-2010, 02:10 PM #7
- Join Date
- Jan 2006
- Atlanta, GA
There's a green light near me, here, in Marietta that is so short from the time it goes green to yellow you can't make it all the way across the intersection before the change. This is only late at night but good grief!"No, I don't skinny-dip. I chunky-dunk."
Sleep Talkin' Man - 10/15/10
04-15-2010, 02:26 PM #8
- Join Date
- Mar 2008
- My perfect beach
I agree with you surfman, and was just having a similar conversation with my driving-permitted teen son yesterday. The yellow lights are too short for the speed limits. I always tell him to accelerate through and risk running the red to avoid being rear-ended at 55 mph. I'd much rather a citation then a seriously injured child.Follow your bliss and the Universe will open doors where there were only walls. ~ Joseph Campbell
My fountain-of-wisdom two-years-now driving male teen cringes because, when approaching traffic signals - ESPECIALLY in the Grand Boulevard area - I tend to ease off the accelerator so that I don't have to lock up the brakes should the yellow show up. "Moooooom, green means GO..."
Two decades ago, it was Fuzz's and my first trip to Fort Walton together and a slightly rainy day when I, not wanting to run a red light with a cop in my car, managed to slide my Firebird TransAm sideways through an intersection. Nobody was hurt, he didn't drop me (though to this day I still have to occasionally endure comments about erratic driving) but I still have flashbacks.
Of course, he's the one who decided to gaze over at the substation while southbound on 331 and henceforth took out several construction barrels with the truck, and later got his hand stuck in a bag of candy at 4 a.m. on patrol and hit a tree. So we are even.Go Seminoles...fight team fight...SCALP'EM!!
04-16-2010, 10:02 PM #10
04-18-2010, 12:11 PM #11
A 5- or 6-second yellow light would probably be a good idea for a multi-lane divided highway with a 45- to 65-mph speed limit range. I do know ticket revenue can be good for the community and an attractive reason for a shorter light, but as someone who has been rear-ended after coming to a yellow-light stop at a short yellow on a 50 mph road, I'm not sure it's the most safety-centric solution. I guess the tickets for violators are also a better solution than making it a toll road. What would increasing it to 6 seconds hurt? Statistics show that this decreases accidents and red-light violations.
I've noticed the changes in speed limit in that part of 98 but never really thought much of it; I figured it had to do with intersections with the N/S roads. It would probably be best to keep 98 west of 331 at 45 or 55, and everything east of 331 at 55 or 65, with the yellow "advisory" mph signs approaching each intersection.
There are some areas around the southeast that do seem like the speed fluctuates either to get your attention or maybe your fines... U.S. Highway 280 from Birmingham to Auburn is almost entirely 55 or 65 MPH. Then there is Harpersville. The road and traffic conditions are the same as (and even lighter than) comparable areas along 280, yet in a 1.5 mile stretch, the speed limit goes 65>55>45>35>45>55>65. The local police force is (or used to be) very attentive, although the current mayor said something awhile back about getting rid of the speed trap image. The issue with Harpersville is this: No one is going TO Harpersville; they are going TO Lake Martin, Logan Martin Lake, Talladega Speedway, Auburn (students or football games). You won't stop in Harpersville and spend money/sales tax unless you need gas or are hungry for a combo meal at Jack's. They need the money, they don't have a toll road, they don't have a Wal-Mart, so they establish a "speed zone" unlike any other on Hwy 280 (although there are several of these on U.S. 331: numerous small towns in Alabama and a bit of a MPH roller coaster in dFS from U.S. 90 to I-10).
How is this for creative revenue? Gulf Shores Parkway/Hwy 31 in Bay Minette is 55 & 45 MPH. There is a school just on the northern edge of town with a "35 MPH When Flashing" sign. School operation hours (extended) are 7:15 AM - 3:30 PM, Mon - Fri. Baldwin County Schools (along with Mobile area) had Spring Break this past week, while the rest of Alabama and much of the southern and eastern U.S. had theirs in March. So in March, the city, county, whomever, left the "flashing light" on 24/7, to get people to slow down or produce revenue, regardless of whether school was in session. In this tight economy where governments in our state (Alabama) are struggling, I can't say I blame them. Perhaps the logic is that if people can afford to go on "Spring Break," then they can afford a ticket.
04-18-2010, 01:40 PM #12
Are concerns about the timing being taken to the Department of Transporation? That is the agency that sets up the signals; Walton County has nothing to do with it...trust me.
DOT's local office is in Chipley, unless they've opened one closer, and with budget cuts, I doubt it.Go Seminoles...fight team fight...SCALP'EM!!
I'm more frustrated with the inconsistencies of law enforcement on the roads than the stop lights. Going East out of Sandestin you hit a 55MPH near the Donut Hole that turns back to a 45 near the post office, then back to a 55 near the new Publix.
I've aggressively been passed by Walton County's finest while going 51 in a 45 like I was standing still. Then an hour later coming back, the highway patrol is pulling people over in that very same stretch for speeding.
I wonder how often the highway patrol pulls over cops (or vice versa) for speeding or do they just understand that when you need a donut...you need a donut.
04-23-2010, 06:07 PM #14
I've seen LEOs speed too, some simply because they can...but most of the time, they are responding to a call, and the general motoring public hasn't a clue that is why they are purposefully driving faster than everyone else.Go Seminoles...fight team fight...SCALP'EM!!
04-24-2010, 10:02 AM #15
- Join Date
- Jan 2006
- Backatown Seagrove
I commute said stretch of HWY daily. I too wonder why the eastbound lanes from Mack Bayou to near the post office are 55 MPH while a larger stretch of westbound 98 separated only by a neutral ground from the eastbound lanes is 45 MPH? My only complaint about the lights is that it seems that some mornings if you don't haul boogie from the red light at 30-A/98 you will miss the green light at one of the Hewitts, and subsequently hit reds at Mack Bayou, Grand Blvd, Sandestin, etc.
I for one wish that the lights would be programmed to blink before 7AM on HWY 98. This is how it works once you pass through Sandestin (headed west) in the mornings and there is no trouble.
Or we could lower the speed limit to 45 MPH and all drive LSVs
04-24-2010, 01:24 PM #16
- Join Date
- Mar 2008
- My perfect beach
04-24-2010, 03:07 PM #17
04-24-2010, 03:14 PM #18
04-24-2010, 05:41 PM #19
04-24-2010, 09:23 PM #20
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