I just don't get this

[wsbob]

Good point Haven. I drew that conclusion without actually looking at any of the studies Vincent says are out there revealing that longer yellow lights keep people from running red lights. The idea that this can work is a very attractive idea. When I read it, it seemed a bit unrealistic, but maybe it works under certain situations.

Apparently not though, at "...the traffic signals on either side of I-5, exit 290 (Lake O-Durham exit)". Maybe some other kind of solution is required to keep people from running reds there. Meanwhile, it sounds like a good place for the police to make some money by issuing some citations.

Originally Posted by Haven_kd7yct

Extending the yellow is an interesting idea, on paper-- but in practice, you'll see a lot more people trying to get through the intersection because "it wasn't red yet".

From my unofficial and unscientific observations, people want to get through the intersection as fast as they can. That means they'll run the yellow-- and the red, if they're following someone who just ran the tail-end of the yellow.

The best place to view this phenom: Down here in Tualatin/Lake Grove, at the traffic signals on either side of I-5, exit 290 (Lake O-Durham exit). Watch 'em as they are getting on or off the freeway. There's so much squeezing the lemon out here, the streets are awash in lemonade-- and orangeade, when the light goes from yellow to red and people are still going through the intersection.

I've seen strings of cars 3 and 4 long running the red, that's 3 and 4 cars leaving the stop line after their light has turned red.

That's after 3 or 4 cars have also run the yellow, which for the light turning onto I-5 south, seems pretty long anyway.

[vincentpaul]

This isn't new data. Its been accepted by transportation engineers for years. Extending the yellow does NOT decrease driver reaction time, it DOES decrease the incidence of red-light running. If you extend it long enough, you can get almost to zero unimpaired drivers running the light. People actually understand the risk calculation involved, and react properly to it if given enough time to react. When they are pressured into the decision they make bad decisions. The problem is that by increasing the yellow you decrease the road's carrying capacity.

"The data show that the percentage of last-to-cross vehicles clearing the intersection (T+0.2) seconds or more past the yellow onset was not appreciably changed by the extension of the yellow phase."
The Influence of the Time Duration Of Yellow Traffic Signals On Driver Response, Stimpson/ Zador/ Tarnoff, ITE Journal, November 1980

"Research has consistently shown that drivers do not, in fact, adapt to the length of the yellow."
Determining Vehicle Change Intervals - A Proposed Recommended Practice", ITE, 1985

"Olson and Rothery reported in 1972 that their research showed that drivers were "virtually" certain to stop if their required deceleration rate was less than 8 feet per second squared and virtually certain to continue if the deceleration rate required was in excess of 12 feet per second squared"
Determining Vehicle Change Intervals - A Proposed Recommended Practice", ITE, 1985

"The average implied deceleration rate of the group with the highest crash rate was slightly over 13 feet per second squared, and the deceleration rate for the group with the lowest crash rate was 8.5 feet per second squared"
"Effect of Clearance Interval Timing on Traffic Flow and Crashes at Signalized Intersections", Zador/ Stein/ Shapiro/ Tarnoff, ITE Journal, November 1985

And my main point is that you cant expect human beings to react like robots, they're going to make judgment errors, and they often should not be held responsible for judgment errors, even when they are at "fault." It should take something more than mere "fault" to incarcerate someone. Criminally negligence is the current standard, and its a good one. If this was a close run of the red light, it'd be difficult to persuade a jury. You'd be hard pressed to find an honest driver of any experience who wouldn't admit to having run one at some point in their life.

By the way, I once used a transportation engineer as an expert in the trial for criminally negligent homicide of a client who ran a red. The jury was persuaded that there was no criminal negligence.

[Curtiss]

Epic post man. Honestly, thank you for your contribution to this blog.

[Attornatus_Oregonensis]

Indeed. Doesn't the Olson and Rothery research suggest that controlling speed - not setting lower speed limits, but actually achieving lower motor vehicle speeds - would mitigate this problem?

[wsbob]

It's a little hard to understand the study jargon in the sub-quotes below, and easily draw from them, the conclusion that longer yellow lights result in the reduction of people blowing red lights. That seems to be what they're saying though. On its own, the first one seems to suggest that lengthening the yellow light doesn't change the number of people blowing the red. Second to the last sub-quote says "...that drivers were "virtually" certain to stop if their required deceleration rate was less than 8 feet per second squared...". So I suppose they're saying that if the length of the yellow light gives road users sufficient time to slow down at a certain rate of speed, they'll do that rather than cruise through the light.

So I wonder how the light settings for the intersection related to the incident in Vancouver jive with the specs of this study.

" Investigators believe the Nissan Pathfinder went through the intersection with the red traffic light at Columbia Street and Fourth Plain and crashed into a Land Rover Discovery. Then, the Land Rover went on to hit a bicyclist.

"The Discovery rotated counter-clockwise striking a bicyclist that was also heading southbound next to the Discovery. The Discovery rolled onto its passenger side, ending up at the southwest corner of the intersection. The Nissan Pathfinder ended up facing east in the middle of the intersection," Lt. Martin Holloway, Vancouver Police Department said. "The bicyclist was knocked to the ground." " (excerpt from KGW story located on the first post)

Sounds like that driver cruised through the red light at a pretty good clip. Could be, no duration of yellow light would have got him to stop, regardless how long it was.

Originally Posted by vincentpaul

This isn't new data. Its been accepted by transportation engineers for years. Extending the yellow does NOT decrease driver reaction time, it DOES decrease the incidence of red-light running. If you extend it long enough, you can get almost to zero unimpaired drivers running the light. People actually understand the risk calculation involved, and react properly to it if given enough time to react. When they are pressured into the decision they make bad decisions. The problem is that by increasing the yellow you decrease the road's carrying capacity.

"The data show that the percentage of last-to-cross vehicles clearing the intersection (T+0.2) seconds or more past the yellow onset was not appreciably changed by the extension of the yellow phase."
The Influence of the Time Duration Of Yellow Traffic Signals On Driver Response, Stimpson/ Zador/ Tarnoff, ITE Journal, November 1980

"Research has consistently shown that drivers do not, in fact, adapt to the length of the yellow."
Determining Vehicle Change Intervals - A Proposed Recommended Practice", ITE, 1985

"Olson and Rothery reported in 1972 that their research showed that drivers were "virtually" certain to stop if their required deceleration rate was less than 8 feet per second squared and virtually certain to continue if the deceleration rate required was in excess of 12 feet per second squared"
Determining Vehicle Change Intervals - A Proposed Recommended Practice", ITE, 1985

"The average implied deceleration rate of the group with the highest crash rate was slightly over 13 feet per second squared, and the deceleration rate for the group with the lowest crash rate was 8.5 feet per second squared"
"Effect of Clearance Interval Timing on Traffic Flow and Crashes at Signalized Intersections", Zador/ Stein/ Shapiro/ Tarnoff, ITE Journal, November 1985

[bikerinNE]

Green, continue through intersection, yellow means to "clear" the intersection, red means to stop. Yellow does not mean to try and enter the intersection.

[vincentpaul]

Originally Posted by Attornatus_Oregonensis

Indeed. Doesn't the Olson and Rothery research suggest that controlling speed - not setting lower speed limits, but actually achieving lower motor vehicle speeds - would mitigate this problem?

Yep. When you get a group of average folks together and actually get someone to explain the data to them, they understand that the whole traffic network is put together, in the main, so as to maximize traffic flow with whatever the designers decide is an acceptable level of accidents. The designers KNOW that they can reduce the number of accidents further.

Off topic: To be pro-cyclist, do you have to be anti-driver?

[vincentpaul]

Originally Posted by wsbob

"The Discovery rotated counter-clockwise striking a bicyclist that was also heading southbound next to the Discovery. The Discovery rolled onto its passenger side, ending up at the southwest corner of the intersection. The Nissan Pathfinder ended up facing east in the middle of the intersection," Lt. Martin Holloway, Vancouver Police Department said. "The bicyclist was knocked to the ground." " (excerpt from KGW story located on the first post)

Sounds like that driver cruised through the red light at a pretty good clip. Could be, no duration of yellow light would have got him to stop, regardless how long it was.

I owned the original 1985/86 Pathfinder. They were a great, lightweight sport-utility. There wasn't even a sport-utility category back then. They're about twice as big today. Mass consumption (pun intended) has given the average suburbanite death on wheels. Hmmm, 1/2 MV squared.........A pathfinder can easily push a Discovery around at relatively legal or reduced speeds. Unless we want to immediately leap to the worst possible conclusions based on the article, we really don't have any idea of whether this person simply committed human error or was criminally negligent. I may ride a bike, but it doesn't make me better at decision making than the average driver. I broke an arm on my bike last year just to prove that theory. : )

[wyeast]

Just because there are few criminal charges, don't think for a moment that the Discovery driver and the cyclist don't have the option in civil court against the Pathfinder driver. Not every traffic accident results in an arrest. It's not uncommon, particularly when there's only minor injuries involved, that the police only go as far as setting up who's at fault, then the rest gets squabbled amongst the insurance agencies. (or in this case, suing an uninsured driver)

It's simply a matter of not having an actual law that says "Don't be a jack*** and hit someone"

[djasonpenney]

I know it's an extreme notion, but have we so totally abandoned making people accountable for their mistakes?

A six month suspension if you've found to have violated a traffic law and caused an injury accident seems to me to be pretty appropriate. It would really put the fear of G-d into people taking risks on the road, especially if their livelihood depends on polluting the air and giving money to terrorists.

I'd make the interpretation pretty simple. Were you in an injury accident? Were you driving drunk, speeding, failing to yield the right of way, or disobeying a traffic control device? Congratulations; you're a pedestrian/bicyclist/transit commuter for the next six months. Violate the terms of your suspension and face fines, civil forfeiture of your vehicle, and possible jail time.

I know, it's just fantasy. But think of how much calmer it would make drivers.

Originally Posted by vincentpaul

Hmmm, I'd want to do a risk/benefit analysis on that idea. Setting the standard at "fault" would pretty much grind society to a halt.

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