Red Light Cameras

Red light cameras exist to exploit the pseudo science traffic engineers use to calculate the duration of the yellow signal light. The pseudo science consists of many math and science errors and false assumptions that create involuntary red-light runners. Because all traffic engineers follow the same yellow light practice, these errors appear at every signalized intersection. The errors are systematic such that anyone who knows the math can predict where the most red-light runners are going to be. The red-light camera companies know that bad engineering, not bad driving, is responsible for the vast majority of red-light runners. But in order to make money, the companies conceal the errors of engineers. Companies, traffic engineers and city officials shift the blame to drivers. The drivers become a scapegoat for bad engineering as well as a source of revenue for company and government. To sum it up, red-light camera programs are a charlatan fraud scheme based on bad physics.

Dilemma zone. The engineer's calculation for the duration of the yellow light always produces a defect called a dilemma zone. A dilemma zone is a segment of roadway upstream from the intersection where if a driver is in it when the signal light turns yellow, the driver will neither have the distance to comfortably stop nor the time to reach the intersection before the light turns red. The driver must run a red light. Video 4, below, describes dilemma zones.

Where the math errors most oppose the physics of traffic motion, the most red-light running and crashes occur. To learn the math and the physics, watch the first 3 videos.

Video 5 shows what a "red-light violator" usually looks like in the eyes of a red-light camera firm. In their marketing campaigns, red-light camera firms only show camera clips of nasty T-bone collisions in order to scare the city council into buying their product. As you will see in video 5, those clips are false-advertising. Had the camera companies shown who is their usual red-light violator, the city council would kick the companies out the door.

For those who want to laugh, watch video 6. Video 6 was produced by Blame Society--a Wisconsin comedy company. Blame Society's video tells the story of Cary, North Carolina's red-light camera program. It is funny and yet true.

1. Yellow Light History and Math

2. Errors and Omissions

3. Legal Problems


4. Yellows Explained w/o Math

5. Red-Light Cameras Clips

6. Funny yet True

Fearrington, Malmrose vs City of Greenville

North Carolina Appellate Court Decision - Greenville

North Carolina Appellate Court Decision - March 15, 2022

Greenville loses. Do you still have to pay your tickets? No. You never had to. Paying red light camera tickets has always been voluntary in North Carolina.

North Carolina Appellate Court Decision - Greenville

NOTICE: Seeking Plaintiffs for Wilmington and Fayetteville

We are starting a lawsuit against Wilmington and Fayetteville. We need plaintiffs who received a red light camera ticket. To be a plaintiff, you must have legal standing. To have legal standing, you must appeal your ticket and lose the appeal: sign up for an administrative hearing. At the hearing, claim 1) that 90% of gross penal fines are not going to the public schools, 2) that in North Carolina, the city cannot enact a local health law. (Red-light cameras affect public safety; therefore, they affect health), 3) that the yellow light is too short, and 4) that the red-light cameras are not allowed to be present because they have been installed by a company not licensed to practice engineering.

After the hearing is over, the city must find you guilty. Guilty is good in this case. You must pay $50 (Wilmington) or $100 (Fayetteville). Do these things and you have legal standing. Call 919-815-0126 for more info.


ITE Corrects Yellow Change Interval

ITE Journal March 2020 ITE Signal Guidelines

The Institute of Transportation Engineers (ITE) is a private organization that establishes the practices Departments of Transportation use to set the length of the yellow light. Since 1965, ITE has been publishing a practice that causes every driver in common scenarios to inadvertently run red lights. Over 90% of red-light running is caused by ITE's errors and omissions. About 9.99% of the remaining 10% are caused by traffic engineering errors other than the yellow light.

After 20 years of confrontation, on March 1, 2020, my colleagues and I led ITE to confess that its practice has been wrong. It is a practice that has killed or injured millions of drivers. As the first step, ITE chose to correctly apply the mathematical works of Dr. Alexei Maradudin (1960-2018), and to newly adopt the mathematical works of Dr. Chiu Liu (2002), Brian Ceccarelli (2010), Jay Beeber (2012) and Mats Järlström (2013).

Beeber Maradudin Jarlstrom

Jay Beeber, Alexei Maradudin and Mats Järlström

The ITE Journal contains an article by Jay Beeber. Beeber correctly explains Järlström's extended kinematic equation. Beeber's explanation is 100% correct not only about Järlström's equation, but also about the underlying physics principles of what a yellow light is supposed to be. Beeber also includes brief treatises on the requirements for engineering tolerances for law enforcement and the correct application of physics dynamics for the road-grade adjustment.

You may download the Excel spreadsheet to compute the new official yellow change intervals. I included the yellow change intervals for commercial vehicles so that one can see the range of valid yellow change intervals which accommodate all allowed drivers on the road. ITE now officially acknowledges a valid range of perception-reaction time and deceleration values, not just the one average value for passenger sedans on dry pavement. ITE does make a strong statement that zero-tolerance by red-light camera firms is bad.

The Guidelines document, though it gets the formula right, leaves 4 other errors in tact. (Watch video 2 above.) Also one can read the ITE Guidelines and construe use-cases that undermine the physics.

It is important to know that traffic engineers are not legally bound to use the Guidelines. ITE has no legal authority. ITE is a private firm, like Walmart. However there is one exception. The State of Virginia has a statute requiring traffic engineers to use the ITE practice. This exception is actually illegal itself. An attorney can argue that the statute conflicts with the State's Engineering Practice Act. Engineering is supposed to be determined by engineers, not legislators.

Traffic engineers have been using the bad ITE formula since 1965. Even though ITE has corrected its formula, States' traffic engineers will not implement the correction. Implementation means confession. Confession means liability for having killed hundreds of thousands of people, physically injured millions and financially ripped-off hundreds of millions via photo-enforcement. The engineers rather harm others than humble themselves. Astonishing as this sounds, as recorded in depositions on this web site, most traffic engineers neither know basic physics nor believe in physics. Those few that understand physics are gaslighted by their ignorant peers. Such ignorance, beliefs and unwillingness to safeguard the public's life, health and property, are all criminal acts for licensed professional engineers according to the engineering practice statutes.


Physics and Math

The Problem of the Amber Signal Light in Traffic Flow

The Problem of the Amber Signal Light in Traffic Flow; Gazis, Herman, Maradudin

Gazis, Herman and Maradudin (GHM) co-authored this paper in 1959. In 1965 ITE miscopied this paper's equation 9 into its Traffic Engineering Handbook. By omitting GHM's "Analytical Considerations", ITE has been instructing traffic engineers to abuse this formula for over 50 years.

The Problem of the Amber Signal Light in Traffic Flow

Determination of Left-Turn Yellow Change and Red Clearance Interval, Liu

The American Society of Civil Engineers (ASCE) Journal of Transportation Engineering published Dr. Chiu Liu's paper in 2002. This paper is the follow-up work to Gazis, Herman and Maradudin. Dr. Chiu Liu's formula computes the minimum yellow duration which allows all traffic to move legally. Chiu's formula is equation 13 on page 454.

The beginning of the paper states explicitly that the turn lane yellows must be longer than the straight-through. The new ITE guidelines say that Liu's turn lane yellows will be shorter than the straight-through.

Extended Kinematic Equation Explanation

Järlström's Extended Kinematic Equation Explanation, Beeber, ITE Journal

Mats Järlström's equation is for both right and left turning. This article appears in the March 2020 issue of the ITE Journal. It is a perfect explanation of both Järlström's equation, the purpose of the yellow light, and the general principles of tolerances and when it is correct to use the grade adjustment.

Extended Kinematic Equation, Jarlstrom

Extended Kinematic Equation, Järlström

This is Mats Järlström's technical paper describing his turning equation. The GPS/Race-Logic data Järlström uses profiles a right-turning vehicle's approach to the intersection. It is beautiful. One can visually compare reality with his equation of physics.

Järlström's equation models a different type of vehicle approach than Liu's equation. Yet both equations are correct. The equations yield similar values. Using either equation is good practice.

Järlström's equation has the added benefit of capping the yellow change interval to the stopping time--which would be the time it takes a driver to make a U turn.


Yellow Change and All-Red Clearance Equations of Physics, Ceccarelli

This paper lists the physics equations which allow different types of traffic movements to legally enter an intersection.

Equation 14 differs from Liu and Järlström. Equation 14 models the velocity/distance profile for the fastest turning approach into the intersection. Liu's and Järlström's equation models the profile for the slowest turning approach.

Derivation of the ITE Yellow Change Interval Formula

Derivation of the ITE Yellow Change Interval Formula, Ceccarelli

This paper shows the mathematical steps to derive the yellow change interval formula, both the ITE through-movement and Liu's equation from F= ma--Newton's second law of motion. The paper describes the physics and the assumptions.

Uncertainty in the Yellow Change Interval

Uncertainty in the Yellow Change Interval, Ceccarelli

In the presence of the misapplication of stochastic methods, like using the average perception/reaction time or 50th percentile deceleration, one must compute tolerances for the yellow change intervals so that law enforcement does not punish drivers entering the intersection on red within the uncertainty of engineering calculation. The method to do this is called error propagation. This paper describes the mathematical technique of propagating errors. Typical tolerances range from about +/- 2.0 to 3.5 seconds.

It is the responsibility of the traffic engineers, not the red-light camera industry, to compute the tolerance. The red-light camera grace period must be at least the tolerance.

Five Major Engineering Errors and Omissions

The Yellow Change Interval: Five Major Engineering Errors and Omissions, Ceccarelli

This paper explains the five major ways traffic engineers as a profession misapply the physical and mathematical sciences thus putting in harm’s way the life, health and property of the public.


Contrast between Practice and What is Required

Yellow Time: Contrast between Practice and What is Required, Ceccarelli

How much yellow time do reasonably-perceptive drivers need? Do commercial vehicle drivers need more time? This chart reveals how traffic engineers systematically short the yellow for reasonably-perceptive drivers and for various of types of vehicles.

(Click here for North Carolina specific.)

Misapplied Physics Profits Red Light Camera Companies

Misapplied Physics in the International Standards that Set Yellow Light Durations Forces Drivers to Run Red Lights, Ceccarelli

This paper describes the formula, what it does and how today's traffic engineers misapply it. This paper also presents red light camera citation data showing how minor changes in yellow light durations dramatically and permanently affect red light running counts.

Maradudin's Letter to ITE Condemning ITE for Misapplying His Formula

Letter Condemning ITE for Misapplying His Formula, Maradudin

This is a letter (July 2015) from Professor Alexei Maradudin, the last surviving inventor of the yellow change interval formula. In an upcoming yellow light guideline which ITE is about to publish (called the RP), ITE misquotes Maradudin. Maradudin does not take kindly to that. Maradudin does not like ITE misapplying his formula to turning motions and to any motions impeded within the critical distance. Maradudin does not like that ITE intentionally and knowingly forces drivers to run red lights by establishing a standard which sets the speed used in the formula to values less than the posted speed limit.

Yellow Change Interval Dos and Donts

Dos and Don'ts of the Yellow Change Interval Formula, Maradudin

This is a letter (July 2013) from Professor Alexei Maradudin, the last surviving inventor of the ITE yellow change interval formula. Every Department of Transportation in the world does the don'ts which cause drivers to inadvertently run red lights.

Blinded By The Truth

Does the Multibillion-Dollar Red Light Camera Sector Owe Its Existence - and Profits - to Traffic Engineers' Misapplication of the Yellow Change Interval Formula?, Ceccarelli, Shovlin

Traffic Technology International, a London-based journal, published this cover story about red light cameras exploiting the faulty ITE equation in its October/November 2013 issue. This story summarizes much of the literature on this web site.


Animation Slow Down at Critical Distance Animation Left Turn Slow Down at Line Animation Right Turn Animation Slow to Turn

Animations Illustrating the Problem by Johnnie Hennings, P.E., Accident Reconstruction Analysis, Inc., Raleigh.

The animations are to scale and true to the laws of physics.

In the animations you will see the "critical distance". The critical distance line marks the closest point to the intersection where the driver can still stop safely and comfortably. The line is the point of no return. By federal guideline the amount of time the light is yellow equals the time it takes the driver to traverse the critical distance on the precondition that he travels at the speed limit. You see this fact play out watching the straight-through unimpeded drivers in the following videos. But notice how the yellow will be too short for turning and impeded drivers.

  1. The first animation has the light turning yellow the moment after the left-turning driver crosses the critical distance line. The traffic engineer forces the turning driver to run a red light.

  2. The second animation has the light turning yellow the moment the left-turning driver applies his brakes in order to slow down to prepare for his turn. The traffic engineer forces the turning driver to run a red light.

  3. The third animation shows a right-turning driver. He has the same problem as the left-turning driver. The traffic engineer forces the turning driver to run a red light.

  4. The fourth animation shows a straight-through driver who has to slow down to avoid the car that emerged from a business. The traffic engineer forces the impeded driver to run a red light.

Most States implement a shorter turn lane yellows than through-movement lanes. This demonstrates that traffic engineers do not understand the kinematics of the ITE yellow change interval formula. A new federal guideline called NCHRP 731, formalizes the implementation of the error. One of the 731's authors is Richard Retting, the father of the red light camera industry in America.

I-Team:  Are Yellow Lights Too Short When Making Turns?

I-Team: Are Yellow Lights Too Short When Making Turns?

ABC WTVD, Channel 11, Raleigh, NC: May 5, 2014.

This newscast includes an interview with Dr. Alexei Maradudin, the inventor of the yellow change interval formula. Maradudin rebukes DOTs all over America for their misapplication of physics.

Kevin Lacy, a spokesman for the NCDOT, responded to ABC. Lacy claims that there is no deterministic equation which models all traffic. Lacy is wrong. The deterministic equation not only models all traffic, but all objects in the universe. It is a = v/t, eq. 41 here, of Newton's second law of motion. The equation for turning traffic is eq. 13 here. The red light camera empirical data proves that the deterministic equation is the solution. That should be expected. Everyone (other than traffic engineers) have known about this equation since 1687 when Isaac Newton discovered it.

Johnnie Hennings, P.E., an accident reconstructionist, wrote a rebuttal to Kevin Lacy's/NCDOT's letter.


Television Newscasts

Science Proves Yellow Lights too Short

I-Team: Are Yellow Lights Too Short When Making Turns?

ABC WTVD, Channel 11, Raleigh, NC: May 5, 2014.

Science Proves Yellow Lights too Short

I-Team: Raleigh Fraudulently Issuing Red Light Camera Tickets

ABC WTVD, Channel 11, Raleigh, NC: Feb 5, 2014.

Science Proves Yellow Lights too Short

Red light Camera Traps: Does Science Prove Our Yellow Lights are too Short?

"The Institute of Traffic Engineers miscopied the yellow change interval formula into its 1965 engineering handbook. Traffic engineers, the so-called experts, do not know the math and science behind their own formulas."

CBS WTKR, Channel 3, Hampton Roads, VA: February 5, 2014.

WTKR. Newport News Re-evaluates Yellow Times

Newport News Re-evaluating Yellow Light Times after NewsChannel 3 Investigation

CBS WTKR, Channel 3, Hampton Roads, VA: February 7, 2014.

WTKR - Redflex has Violation Calculator

Redflex Tells Local Cities Where to Put Cameras Based on a Violation Calculator

CBS WTKR, Channel 3, Hampton Roads, VA: February 19, 2014.

WTKR proves what we suspected. Redflex knows physics too. Given the predictable failings of the ITE yellow change interval formula, Redflex wrote a violation calculator to compute exactly where the engineering failures produce the most revenue.