What is the standard length of a yellow light?

Is the timing of yellow lights all the same, or do they differ? It seems the lengths of yellow lights differ, some longer than others, some very short. This makes a difference in one's decisions.

And what constitutes an infraction? Having it turn red while passing the intersection? Middle? End? Again, clarification needed here, especially with the cameras being placed on intersections and high fines being levied.

A: It all depends on who's sitting in the old cardboard box on the corner and what type of tip the traffic officer has given him that day, that dictates how fast the yellow changes to red. Not funny, I know.

Well you may have guessed that there is a specific manual that covers this: Manual on Uniform Traffic Control Devices.

Without boring everyone with a whole lot of mathematical equations, here is the basic to minimum yellow light change interval timing. If the posted speed or prima facie speed is 25 mph or less, the minimum yellow interval is 3 seconds. 30 is 3.2, 35 is 3.6, 40 is 3.9 and 50 is 4.7.

I know for a fact that the yellow interval times at many of the controlled intersections here in Redding are generally a bit longer than required but they are never less than what the manual requires.

As far as what constitutes a violation for failing to stop for a red traffic signal, that too is pretty simple. As long as your vehicle enters into the intersection or is within the intersection before the light changes from yellow to red, there is no violation.

When approaching an intersection controlled by a traffic signal, it's best to look toward the controlling device several blocks ahead. This looking down the road is known as raising your visual horizon or scanning. As we approach the light and it has been green for as long as we have been observing it (known as a stale green), we should be anticipating that a yellow light may be in our future. Depending on the posted speed limit for the roadway, the timing for the yellow lights varies. Through traffic may have a 3- to 5-second yellow, but most left-turn lanes regardless of the posted speed limit will have a shorter time, maybe 3 seconds. The higher the posted speed limit for the roadway, the longer the yellow phase.

Regardless of the timing, the yellow lamp indicates a red light is definitely in your future. If you wish to have a future, you should now consider slowing and stopping as opposed to racing toward the intersection to see whether you can make it into it before the red light.

There are several differently designed intersections that operate on various sensor/video systems that I have spoken of in earlier columns. But the rules regarding stopping for a red traffic signal are very specific. A driver facing a steady circular red signal alone shall stop at a marked limit line. If there's no limit line, the driver should stop before entering the crosswalk on the near side of the intersection. If there's no crosswalk, the driver should stop before entering the intersection.

The vehicle shall remain stopped until the light turns green.

But, I'm not going to go across the intersection, I'm just going to turn right and no one is approaching in the other direction. Except when a sign is in place prohibiting a turn, a driver, after stopping, facing a steady circular red signal, may turn right or turn left from a one-way street onto a one-way street. A driver making that turn shall yield the right of way to pedestrians lawfully within an adjacent crosswalk and to any vehicle that has approached or is approaching so closely as to constitute an immediate hazard to the driver, and shall continue to yield the right of way to that vehicle until the driver can proceed with reasonable safety.

The key word in every case is stop. Cease moving: to come to a standstill or bring something to a standstill. Stop the car! No matter which dictionary you look up the word, it all means the same. The vehicle code does not have an exception rule covering the time of day, the amount of traffic in the area, the "I've got to go to the bathroom" rule.

Once again there is some logic when it comes to the engineering and planning of our roadways and traffic control devices. That makes it much simpler for the rest of us to go out and enjoy the ride.

Sitting at a red light can feel torturously long, but yellow lights often seem suspiciously short. It's not all in your head: some yellow lights are too short. There is an ideal minimum length of a yellow traffic light. You just might never experience it (especially if you're from Chicago).

There's no universal correct yellow traffic light time, since people going 35 MPH will be able to stop quicker than people going 50 MPH. But there are equations to figure out the minimum safe time for a yellow light. The speed limit obviously matters, but so does how quickly a car can decelerate, and whether the road is hilly or level. Plus, you have to account for the driver's "perception reaction time," which is basically how quickly a driver can react to seeing the light turn yellow. And that reaction time can vary from person to person, which is where things get sticky.

That's why a lot of cities are adopting equations to figure out how to set their traffic lights instead of deciding on one uniform time per speed zone. According to a 2012 survey of 200 transportation agencies in the U.S., Canada, and Germany, 40% of the agencies use an equation by the Institution of Transportation Engineers to figure out their yellow lights.

It's a much better system than just picking one time per speed zone, the current Chicago method. Yellow lights were shortened to 3 seconds in 30 MPH zones there, and results have prompted plenty of anger, especially since ticketing has skyrocketed. And an investigation from the Chicago Tribune revealed that some of Chicago's yellow lights were even shorter than the minimum of 3 seconds, and suggests city officials shortened the lights to make money off fining people for blowing them.

The Department of Transportation's traffic manual recommends that yellow lights are between 3 and 6 seconds long. Many cities err on the side of skimpy when they should be laying on the yellow for a little longer, and Chicago is an example of a straight-up bad yellow light policy.

The ITE's equation is an improvement, but there may be an even more nuanced approach transportation agencies could take. Heshem Rakha, a transportation expert and engineering professor at Virginia Tech, headed up a project to figure out a better standard that takes into account the fact that some people just aren't going to react as quickly as others.

"Basically, when you're designing a yellow time, you want to prevent bringing the drivers into what we call the dilemma zone, where you have no good decision you can make," he told me over the phone. Yellow lights that are too short put drivers in the dilemma zone when they get stuck in the intersection or ram their car to a halt and cause a collision. Which is why Rakha's equation tries to pinpoint a more precise (and often, much more generous) length of the yellow light. The dilemma zone is shitty and scary.

Rakha's proposed standard is more flexible than the ITE's, but at the bare minimum with current traffic standards in place, a yellow light in a zone where people are driving 35 MPH should be at least 4 seconds. Chicago's 30 MPH yellow lights last exactly 3 seconds now. For cars to clear an intersection at 99.6% at 35 MPH on Rakha's chart (on a 0% grade, which is what Chicago's flat streets would be on) a light should be 4.9 seconds. Yes, Chicago's speed limit is slightly lower, but come on. The recommended absolute minimum yellow light is 3 seconds. This minimum is not safe or appropriate.

When drivers approach an intersection as the light turns yellow, some people slam the brakes, others race the red. The wrong split-second decision causes accidents and racks up expensive tickets—sometimes far more than necessary. And this is partly because many cities do not allow long enough yellow lights.

This is some bullshit.

Longer yellow lights would give people more time to make it across the intersection without gunning it or slamming on the brakes or racking up a giant fine. Even the standards set by Rakha, which allows for a variety of reaction times, do not take into account distracted driving, speeding, or just plain asshole roadrage. If yellow light times were a little more generous, yes, it would slightly slow the flow of traffic, and cities wouldn't be able to collect as much money from tickets. But too bad, cities! Suck it up and be safer.

How long is a yellow light on a 45?

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How long is a yellow light in Florida?

How long is a yellow light in Illinois?