Tuesday, December 22, 2009

Teaching #1: The Late Merge Awareness Campaign


One might think that Lesson #1 should be the most important lesson.  I would agree.

I have 2 routes that I take home from work at night depending on what my MNDOT traffic map shows for congestion.  One route is on I-94, and the other route is 35W to Hwy 36.  The latter is usually referred to as my "social teaching route". It is inevitable that on this latter route that I put this lesson #1 into practice.  When you shake your fist at me while I speed by in the lane to be closed a 1/2 mile ahead, I'm actually making everyone's trip shorter.  Seriously, it is only about efficiency.  I wouldn't do it unless there was quantitative research behind it.  Here we go.

The debate between “early” or “late” merge seems more appropriate for human behavioral studies of aggressiveness, impatience, self-indulgence, and simple preference. However, there is general agreement in the engineering community on which method works best for each of two scenarios. 


Scenario 1 is when two lanes on the freeway are merging and the traffic density is light prior to, and at, the merge neck.  Additionally, speeds are at the posted limit throughout the pre-merge region.  This is not the category that I am talking about.  This is the 11 AM section of freeway with no traffic on it.  In this scenario, the early merge is most efficient.


I am addressing a second category, that is bumper-to-bumper/stop-n-go traffic for a mile before the merge neck, where the late merge is most efficient.  This is the 5 PM section of freeway where Hwy 280, Hwy 35W, and Hwy 36 all merge and it takes 5 minutes to travel 1/4 mile.  In this scenario the late merge is most efficient for the group as a whole.  The concept of delaying a merge when two lanes are funneled into one, caught on with traffic engineers after studies showed that traffic flow sped up as much as 15% over the old Minnesota “merge early and politely” philosophy.


I won't present all the studies validating this approach, but I will lay out a couple key components of why it is more efficient to merge late in heavy traffic scenarios.  First of all, why would the highway department put a merge "neck" (the spot where 2 lanes finally turn into 1) 1/2 mile ahead if they wanted you to merge now?  If they wanted you to merge now, they would put the merge "neck" here.  Simple but true. 


The second, slightly more complicated reason is based on the "rice test" phenomenon.  In the first case, dry rice is poured all at once into a funnel. In the second case, the same amount is poured slowly. These trials generally conclude about a one-third time savings to empty the funnel via the second method.  Traffic similarly moves slower the more dense it is packed.  The denser the traffic, the smaller the safety cushion around each driver, and the more cautious (i.e., slower) the driver becomes.  Thus, the longer you can spread traffic out over an additional lane between point A and B, the faster traffic gets from A to B.  In a theoretical 1 mile stretch of road, if you have traffic in 3 lanes for 1/2 of the mile and then 2 lanes for the last 1/2 of the mile, it moves more efficiently than if you have traffic in 3 lanes for 1/4 of the mile and 2 lanes for 3/4 of the mile.  Thus, that lane that eventually ends, should be used as additional "bandwidth" until it ends.



A third reason is that a large percentage of drivers in the discontinuous lane brake rapidly to join the end of the forming queue in the lane to be continued – even if their lane is still free flowing. This early merging out of the discontinuous lane is another cause of unexpected braking that sets up perfect conditions for rear-end collisions. Frequently, a driver takes it upon him/herself to be a “traffic cop” and block the discontinued lane with his or her vehicle, preventing those “late” merging drivers from going around the single lane queue. Fifteen percent of drivers admitted to straddling lanes in order to block late merges in construction zones, according to a recent study conducted by the Minnesota Department of Transportation. These behaviors really piss people off and only further the chance of an accident.



The solution from the MN DOT has been a series of electronic signs at merge locations that sense the speed of traffic flow and instruct drivers to "use all lanes" and "merge here" depending on the flow of traffic. 

"Basically, we want drivers to know that under normal traffic speeds, they should try to merge early to avoid unsafe merging maneuvers; however, when traffic is congested, drivers should use both lanes all the way to the definite merge point," said Servatius. "We can't completely rid the roads from congestion in a workzone, but data from the study revealed this method shortened queue lengths by 35 percent and reduced lane changing conflicts," said Mittelstadt. "We also hope for a decline in crashes and aggressive driving behavior." 

Sure there are counter arguments about just waiting your turn.  I agree with those arguments, but the point is that everyone in line is pissed off because things are moving slow.  If everyone understood that lanes merge at a specific spot because that is where they were meant to merge, and everyone used that 3rd lane until it merged, everyone would move faster during rush hour, and people would be happier in the new system.  It is just the transition that hurts.  


Here is an extensive reference from the US Dept of Transportation regarding this topic if you want my references.  In addition, the MN DOT has conducted a study right here at home. I carry a few copies of these studies in my glove box in case I get someone who yells at me with their window down.  I kindly pass them the studies and recommendation from the MNDOT study.  Like I said, it's quantitative.

Thursday, December 17, 2009

Lesson #1: "J'st a wee drop o' the craytchure"

In order to remain most efficient, one must preempt questions about predicted subjects as long as the volume of questions will be greater than the time it takes to preempt.  Thus, this preemptive response to what the title of my blog means.  But that is not Lesson #1 of my social learnings & teachings.  Lession #1 lies in the explanation...

One of my brothers and sister went to Ireland with me 5 years ago.  My sister was in charge of planning one thing: where we would stay at night on our 10-day road trip. That did not happen.  Instead, we drove our minature car until we were tired of sheep and green beauty, and then we pulled into any house that had a sign out for visitors.  A bit of a different setup on the west coast of the emerald isle, where there aren't many hotels.  Rather families, rent out a room in their home that used to be occupied by their now mature and moved-out daughter.  They make you tea and biscuits in the evening, guide you on what pub to drink in that night, and make you a brilliant Irish breakfast in the morning, hopefully containing homemade Irish brown bread.  Brilliant.  But, more importantly, you get a picture of what life is like in an Irish home in small western villages in Ireland.

On our first night in Ireland 5 years ago, we pulled into a farm, and a large 60 year-old woman standing 6ft tall with a plump face, pale as the sheep's underbelly, a cooking apron around her middle, and wearing rubber "shit kickers" on her feet, walked out to greet us.  Agnes welcomed us in, fed us, and sent us down to the seashore to help her extremely shy husband, John, with getting some eggs for breakfast out of the chicken coup (where I think she had just been in her "shit kickers").  We had a brilliant first night in Ireland and I tasted my first homemade brown bread the next morning.  Before we left to hugs from my new favorite Irish woman, and a shy wave from her husband John, I asked Agnes for a brown bread recipe.  She gave it to me with her name and phone number on the back of it.

When I returned home to Minnesota, my brother and I tried to make Agnes' brown bread.  Mistake.  I don't know if it was an issue of not being able to convert metric measurements or if it had to do with the fresh butter from the cows that Agnes used, but it wasn't what we had remembered.

In June of this year, Jessie and I decided that Ireland was the perfect honeymoon location.  After several days on the west coast of Ireland, we found ourselves without a spot to stay one night.  I had Agnes & John's brown bread recipe in our guide book, because I was set on figuring out what was wrong with the recipe on this trip.  I decided that Jessie should meet them, so we phoned Agnes to see if their room was open.  She was extatic.  We arrived to the same scene I had remembered 5 years earlier with John in the field down by the seashore, this time with a new baby donkey that had just been born, and Agnes with an apron on,  "shit kickers" replaced by bright red Crocs this time. I told Agnes that I had made her brown bread with minimal success, and I had to come back for the real thing.  We looked up my entry from 5 years ago in the little log book they keep, and we were there 5 years prior, to the day.


That night, Agnes and ever-shy John, brought out 4 glasses of their wedding Waterford crystal with a little unlabled glass bottle of what looked like whiskey.  She asked if we could toast to the newlyweds with a "wee drop o' the craytchure."  Jessie looked scared, but I said sure.  Agnes poured four shots and toasted in her thick western Irish accent while John quietly smiled at her, "to a long and happy life together, lots of healthy Irish children...Oh, and don't forget what my dad always said, you need a comfortable bed, and a very good pair of shoes...Because if you aren't in one, you're in the other".  With that, she took one of her old oven mitts she was hiding behind her back, stuck 2ft down in her skirt and gave it to us as a wedding present.  An interesting gift from someone who obviously did not need to give us anything.  Later, Agnes explained to me, that there was nothing wrong with the bread recipe she had given me, the ingredients I got from Cub Foods, or my metric measurements.  Rather, it was a well used Irish oven mitt that would be the answer to my brown bread difficulties back in Saint Paul. 

Wednesday, December 16, 2009

Why a blog at this late stage in my life?

Not sure why.  I guess it is because my social interaction meter was below the 35% mark which is greater than two standard deviations from what my psychiatrist recommends.  Or because my wife recommended that I have an avenue for expressing myself and working on my English simultaneously.  She is sick of my recreating lyrics to common songs lately.  Or quite honestly, it is just that the Minnesota winter draws something unique out of people.  With a fire in the living room, frost creating rounded window panes, and perhaps the voice of Garrison Keilor on the potato-powered radio I built as a child, that something for me is a realization that while it is cozy inside, and -22deg F outside, there is still a lot of social teaching and learning that can only happen across the back fence.  Even if it is as cold as frozen crap out there.

Frozen dog crap, is, by the way, amazing.  You can run around the lake at night and not see where you are stepping, land in a pile and it shatters, doesn't stick.

And for the record, as long as I'm laying it all out there, I enjoy linguist comma use, and I like to put the end punctuation outside of the the end-quote mark, when that which is contained inside the quotes is not a complete sentence.  For example, my friend johnny is a heck of a hole digger, I mean one heck of a hole digger, some might even call him a "maestro extraordinaire".

So, whatever the reason is for this blog, if you check in here once-in-a-while, I'll bring you those social learnings and teachings from over the back fence...even when it's cold outside.