top of page

Don't Stop, Stop, Go Faster . . . 

What do you do when you see a traffic signal turn yellow?

Talus Software PLLC does data analytics on red-light camera event data by collecting and correlating that data with traffic signal plans.   The analyses include conclusions regarding the yellow traffic signal lights' unconformity to the laws of mathematics and physics.

In brief, traffic engineers use pseudo-science to determine the duration of the yellow light.   By doing so, traffic engineers force drivers to run red lights.   In legal terms, the engineers apply a standard of care which departs from that required under law.   Therefore, all yellow lights have been determined unlawfully.  The engineers themselves are liable for billions of dollars of red-light camera tickets.    The liability cascades upstream to departments of transportation and municipalities.  Subdivisions of government are also obligated to comply with engineering practice law.  

There are two other websites, and which explain in greater detail.   This site contains a condensed library of documents.

Zip file containing all the preliminary yellow light documents and webinars (all files below)    September 19, 2023

National Society of Professional Engineers (NSPE) Webinar 1 - Physics of the Yellow Change Interval (1 hour).  Zip file containing mp4 file.

NSPE Webinar 2 - Misapplications of Physics to the Yellow Change Interval (1 hour).   Zip file containing mp4 file.

NSPE Webinar 3 - Physics, Engineering and Jurisprudence (1 hour).   For attorneys.  Examples of unlicensed practice of engineering.  Zip file containing mp4 file.

NSPE Webinar 1 - Power Point

NSPE Webinar 2 - Power Point



NSPE Webinar 3 - Power Point


NSPE Webinar 4 - Power Point

ITE's first recommended practice . . . and errors and omissions.

Beeber, Jay; Explanation of the Extended Kinematic Equation for Yellow Change Intervals.   ITE Journal.  This journal has the only correct explanation of the extended equation.   

ITE, Recommended Practice for Yellow Change and All-Red Clearance Intervals.   Rev 3.   This official publication still contains significant errors and omissions. 

ITE, Recommended Practice for Yellow Change and All-Red Clearance IntervalsRev 3, Errata to Rev 3.    ITE did not correct the misapplications of math and physics even in this errata.

Ceccarelli, Brian; Histograms showing number of vehicles entering intersection on red versus time into red.    These histograms prove that the ITE equation is a misapplication of physics.  ITE gives half time to stop (v/2a).   Histograms demonstrate drivers need the full time to stop (v/a).  (Number of vehicles drop to zero at the full time to stop.) 

Beeber, Jay; Compilation of Histograms from American Cities showing the dramatic drop off of red-light running when the yellow change interval increases. 


Ceccarelli, Brian; Four Problems with the Yellow Change Interval Equation 


Ceccarelli, Brian; Derivation of the Yellow Change Interval Formula.    This paper derives the ITE equation from F = ma.   The paper explains how the equation is supposed to be applied.

Ceccarelli, Brian; Shovlin, Joseph; Misapplications of Physics in the International Standards that Force Drivers to Run Red Lights.    This paper derives the ITE equation from F = ma.   The paper explains how the equation is supposed to be applied.

Ceccarelli, Brian; Yellow Change and Red Clearance Interval Solution.   This paper provides a solution for all the cases of traffic approaching an intersection.

Jarlstrom, Mats;  An Extended Kinematic Equation.    ITE chose to adopt this equation in its recommended practice. However to the equation, ITE introduced errors and omissions.

Liu, Chiu; Determination of Left-Turn Yellow Change and All-Red Clearance Intervals, (2002).  Dr. Liu was the first person to discover the mistakes in ITE's equation.  This paper describes equations for left-turn unimpeded movement.    

ITE did not choose Liu's paper because ITE did not understand it.  There are differences between Jarlstrom's and Liu's underlying motion models; however, both would solve the problem for left-turn motion. 

Both Jarlstrom and ITE omit the case of impeded traffic.  

Gazis, Herman, Maradudin.   Problem of the Amber Signal Light in Traffic Flow (1959)

Ceccarelli, Shovlin; Does the Multibillion-dollar Red-Light Camera Sector Owe its Existence - and Profits -- the Traffic Engineer's Misapplication of the Yellow Change Interval Formula?  Traffic Technology International (2013)

Gates, Timothy; Dilemma Zone Driver Behavior as a Function of Vehicle Type, Time of Day and Platooning

This is a one-stop shopping paper on the range of perception-reaction times and deceleration values for different types of drivers.    This paper instantly points out misapplications of stochastic methods in ITE's recommended practice.     ITE uses 50th percentiles, thereby forcing half the driving population to run red lights.

bottom of page