Ask me about being a Traffic Engineer!

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dexter: Jun 24, 2003

cheque_some posted:

OK, that makes sense I guess, although it's interesting because it has always been three signal heads, but the extra green ball was only added recently.

Are you sure it's not because the right arrow is so you can go right without stopping when the adjacent traffic is turning left?

# ¿ Aug 7, 2009 09:06

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# ¿ May 12, 2024 08:04

dexter: Jun 24, 2003

What do you think about one-way streets and the talk about them "dividing communities?" The city wants to turn a few of the roads here into one-way streets but there's a huge opposition from the people living here. Is there really a downside to it?

# ¿ Aug 8, 2009 20:14

dexter: Jun 24, 2003

Cichlidae posted:

Yeah, that's the sort of thing the Autobahn is doing. There are a lot of new technologies just entering the market now, some of them quite innovative. In the Paris Metro, riders can swipe their cell phones at the guichets and pay automatically. Transponders let them use parking garages and tollways from many companies without ever having to roll down a window. They receive a monthly bill showing how much they've been charged.

Personally, though, I'm not a big fan of this. I'm an advocate of privacy, despite the tremendous increases in capacity that could occur if every car was being tracked. Additionally, I prefer to pay in cash so that I don't get any surprises on my credit card. I'm sure attitudes will change on this gradually, for better or for worse.

Another problem, and probably the biggest barrier to this sort of system in the USA, is the national policy document SAFETEA-LU. Providing a facility that is only accessible to those with credit cards, bank accounts, fixed addresses, or phone numbers could be considered discrimination against lower-income and disadvantaged groups.

Finally... Batman Avenue?

California's toll roads are a hybrid of that. Fastrak works on all tolled bridges and toll roads. You just prepay $40 or whatever and it's debited from your Fastrak account balance. The transponders are the same as EZ Pass except you don't have to slow down for it. You can drive through Fastrak lanes at 80mph with no problem (aside from a possible speeding ticket.) If you're not a Fastrak account holder you sit in line at a regular toll booth.

There are Fastrak roads that don't have normal toll booths but that's restricted to express lanes only (I-15 in San Diego, SR-91 in Orange County.)

# ¿ Aug 19, 2009 02:32

dexter: Jun 24, 2003

Cichlidae posted:

These guys know how it's done. I'm glad we don't have any isolated, small towns up here, because that would be tough to deal with. That, and I'd have to take off my dress clothes when I went to meetings with them. Lame!

So how were they issuing tickets outside their city limits, anyway? I thought police couldn't work outside their jurisdiction. I only see the staties issuing tickets on interstates around here. I guess it makes sense, though. If you're an officer and you see someone breaking the law, you stop them, no matter where you are.

If Oregon is like California then any peace officer can issue citations/make arrests anywhere in the state.

# ¿ Aug 22, 2009 08:55

dexter: Jun 24, 2003

Choadmaster posted:

To the best of my knowledge this is not true for California. The only two groups with that ability are the Highway Patrol and the University of California police departments. Yes, the latter seems sort of odd but I think it's so the UC cops can aid local departments in dealing with student-related issues regardless of jurisdiction. I've seen my local UC police giving speeding tickets on the highway adjacent to campus - but I was told by a friend who worked for the UC police that if they stray too far from campus it starts to piss off the CHP (this is the same reason local cops here tend not to police the highways even inside their jurisdiction).

Edit for more info.

California police officers have primary jurisdictions which are normally limited to their city or county. CHP, UC and CSU departments have primary jurisdiction anywhere in the state according to 830.2. 830.1 covers other peace officers:

quote:

(a) Any sheriff, ... any police officer, employed in that capacity and appointed by the chief of police or chief... is a peace officer. The authority of these peace officers extends to any place in the state, as follows:
(1) As to any public offense committed or which there is probable cause to believe has been committed within the political subdivision that employs the peace officer or in which the peace officer serves.
(3) As to any public offense committed or which there is probable cause to believe has been committed in the peace officer's presence, and with respect to which there is immediate danger to person or property, or of the escape of the perpetrator of the offense.

Local departments here constantly issue citations for violations well outside their primary jurisdiction. They won't sit on the shoulders and such to run traffic but will ticket you for anything they observe while traveling. Maybe it's a San Diego thing that other departments are more strict outside of their city, I don't know. Sorry about the derail.

# ¿ Aug 23, 2009 00:38

dexter: Jun 24, 2003

Tool Maker posted:

I've seen one of those before, in Lynn, near North Shore Community College. It never fails to baffle me.

There's some in downtown San Diego and they work pretty well. Parking in them is a pretty significant fine so they're normally open for a decent amount of time before and after the period specified on the sign.

# ¿ Sep 1, 2009 07:26

dexter: Jun 24, 2003

Bold Robot posted:

There is a stretch of freeway near my old house in Oakland that has something that I have never seen anywhere else in the country.

See this exit from 580 onto MacArthur Blvd? Maybe a quarter mile or so before the exit, around the overpass you can see if you track the freeway a little bit to the west, there is a sign that indicates that during rush hours (I think it's 4-6pm), you are allowed to drive on the shoulder. Shortly before the offramp, the shoulder traffic is instructed to either merge back to the left or to exit the freeway.

Why was this done? The freeway is already four lanes - why put in this ersatz one for a few hundred feet? Is this a common practice? It's a pretty substantial shoulder, and I used to take advantage of this sign all the time, but it still seems strange.

There's an area of the 215 in Riverside County where everyone exiting stays on the shoulder and out of the regular traffic lanes. There's no signs for it or anything; it just seems it's something everyone there does.

# ¿ Sep 12, 2009 20:57

dexter: Jun 24, 2003

Ripper Swarm posted:

They'd have to do it by mile, not time; I can't imagine the road rage people would give you if you managed to close a motorway and started costing them serious money! I imagine pricing would be dependant on type of road/time of day so being on a major motorway at 9am would be most expensive and being on a rural back road at 3am would be practically free. That would mean if you do the same route each weekday, it would cost you the same amount each day.

On the express lanes on I-15 in San Diego they do congestion-based pricing per mile. It starts out at $0.80 for the entire 16 (soon to be 20) mile stretch but ranges up to $18 before shutting it down to non-HOV traffic based on traffic volumes. If you enter when it's $0.80 you only pay $0.80 for the entire trip regardless of traffic volumes.

# ¿ Oct 13, 2009 18:03

dexter: Jun 24, 2003

Wiggly posted:

California is very big on ramp metering. I cannot remember the last freeway on-ramp I was on that did not have a metered ramp (not that they are on all the time). On the newer stuff, they even mirror the red light on the back of the signal so that the CHP officers can sit on the shoulder and see if people are running the red light.

Which brings me to a question. Are there any states that are ahead of the game with regards to traffic engineering and set trends for the country?

We have one freeway in Southern California where all lanes of the freeway are metered and traffic transitioning from another freeway isn't.

# ¿ Oct 29, 2009 20:05

dexter: Jun 24, 2003

Do you know what those lines painted in a triangular shape perpendicular to a street are for? They're only used in two places in San Diego that I can think of and one of them was added very recently. Basically they look like this in each lane.

code:

     	-------------------

	   -------------

	      --------

	        ----

	         --

dexter fucked around with this message at 02:16 on Nov 19, 2009

# ¿ Nov 19, 2009 02:11

dexter: Jun 24, 2003

Cichlidae posted:

Those mean "slow down/use caution." Often used before sharp curves or, around here, crosswalks. For those of us in Connecticut, you can find them at the Pratt and Whitney plant in East Hartford. Generally, the lines get closer together as they go.

A similar thing I encountered in France: raised bars in the ground on rural roads approaching a village. Wakes you up and reminds you to slow down before the village.

Ah, okay. They're used when you're approaching "downtown" La Jolla. It's a posted 35mph but the average through there is normally at least 50mph.

# ¿ Nov 19, 2009 07:32

dexter: Jun 24, 2003

Socket Ryanist posted:

Using the center turn lane as an accel/decel lane is illegal everywhere as far as I know. Stopping in it, however, is not only legal but recommended in some states.

It's legal in California as long as you exit it within 200 feet. Why is this illegal in other states?

CVC 21460.5 posted:

(c) A vehicle shall not be driven in a designated two-way left-turn lane except when preparing for or making a left turn from or into a highway or when preparing for or making a U-turn when otherwise permitted by law, and shall not be driven in that lane for more than 200 feet while preparing for and making the turn or while preparing to merge into the adjacent lanes of travel. A left turn or U-turn shall not be made from any other lane where a two-way left-turn lane has been designated.

# ¿ Nov 29, 2009 03:02

dexter: Jun 24, 2003

Cichlidae posted:

I haven't ever seen someone get pulled out of an HOV lane. There's no left shoulder, and it would be imprudent to pull into the divider, not to mention there's almost nowhere a trooper could park that would let him both count the number of occupants and chase someone down.

In San Diego CHP either sits in the middle of the freeway behind a bridge support or just does 15-20mph faster than the rest of traffic and looks into each vehicle. If you have a Fastrak transponder there's a light above each lane every few miles that illuminates when a vehicle with a transponder goes under it.

Gotta love the people who give you the finger for slowing down in the carpool lanes... 1/4 of a mile before they get pulled over by the same motorcycle officer who sits on the shoulder almost every day.

# ¿ May 28, 2010 04:42

dexter: Jun 24, 2003

Silver Alicorn posted:

Well hey, it turns out there's a roundabout practically in my backyard! Heck if I know why it's there, though, because it's a low-traffic road and it's surrounded by normal four-way-stop intersections.

Google maps

Why would there be just one roundabout in the middle of nowhere?

It's better than this retard poo poo in Point Loma. The best part is they don't light up, they're just poles in the middle of the street. Have fun driving through there for the first time at 2am when the power is out. The only place in the city I can think of that has real roundabouts is Bird Rock and the residents aren't too happy about them.

# ¿ Oct 20, 2010 10:16

dexter: Jun 24, 2003

Choadmaster posted:

Sorry to hear about your accident, Cichlidae, glad to hear there was no permanent damage to you or anyone else though.

Are you really allowed to drive a segway on named streets? I thought they had to be driven on the sidewalk. But they are motorized... it's an interesting question.

Seriously though, I'll bet it's all politics at this point. Inside a housing development (which itself will be named after the "[plant-related] + [geographic feature]" rule) every street will be named after a tree. Outside of that, around here on a local level they tend to get named after 'important' people, and on a larger (state) level, numbered stuff (like highways/freeways) have sections that are either named after some major destination ("San Diego Freeway") or named after some dead guy ("[Dead Cop] Memorial Highway").

Older street names are the best; it seems like people just called poo poo whatever they wanted until it stuck. We have a few interesting street names here:
Salsipuedes ("Get out if you can!")
Quarantina (there was a quarantine there... Okay, not too exciting, but why name the street after it?)
Indio Muerto (Surveyor: "Dude, there's a dead Indian laying here." Dude: "Gross, I'll call Waste Management on my iTelegraph and have them pick it up. Where should I tell them to find us? This little strip doesn't have a name yet." Surveyor: "Well now that you mention it....").
Canon Perdido ("Lost Cannon" - in the 1840's some kids thought it would be funny to steal a cannon from the military and hide it... it was found rusting in a creek 11 years later.)

So much better than "Fig" and "Walnut". Of course, even of the old-time street names, 80% are names of town VIPs. I suppose things haven't changed TOO much.

All the streets in my area are named after other beach cities, real creative guys. Nothing tops Bloody Dick Road in :wtf:

though.

# ¿ Oct 27, 2010 07:32

dexter: Jun 24, 2003

Choadmaster posted:

Why does the Northeast love tolls so much?

I guess they have a problem with using public funds for roads or just can't find funding for them? Orange County, CA has a few freeways that were only able to be built as toll roads because Orange County was broke as poo poo at the time. 20+ years later they're still toll roads.

San Diego just pays for its freeways with sales taxes. We've had a 1/2 cent sales tax for the last 20 years (and goes through 2048) to pay for (among a lot of other things) about 70 miles of this:

(14 lanes, physically separated HOV/toll lanes, direct access to those lanes)

# ¿ Dec 14, 2010 09:56

dexter: Jun 24, 2003

Silver Alicorn posted:

What's fun is to go down those HOV lanes and realize that almost every car in the regular lanes has only one occupant.

Know what's even more fun? Paying my $0.90 to drive in those lanes by myself for 16 miles.

# ¿ Dec 15, 2010 07:44

dexter: Jun 24, 2003

Cichlidae posted:

This one was an overhead sign on I-84 in Vernon. We'd just put it up, brand new, a few months beforehand. The dump truck was rolling down the shoulder and forgot to put its bed down. Bam. It was actually suspended in the air; the sign held up, and the support itself is fine. The foundation, though, cracked.

Wanna know how to absolutely RUIN a city for a day? Knock down a huge sign at 7:30am on a freeway that averages 200,000+ cars a day.

# ¿ Feb 5, 2011 06:52

dexter: Jun 24, 2003

grover posted:

The coolest lane shift I've seen is on the Coronado Bridge in San Diego which is a chain of concrete barriers and two bus-sized contraptions that drive the bridge twice a day, shifting the barriers to optimise the bridge for AM/PM rush-hour (no HOV, though). They have it configured such that they don't even have to stop traffic to do it, it's pretty slick.

The express lanes on the 15 here in SD are being reconstructed with that barrier as well. Four reversible lanes separated by a concrete barrier from the main lanes with direct access ramps into the express lanes that only cost me $1.80 to use as a solo driver? :awesome:

I used to be able to drive the 17 miles from home to work without touching a regular freeway lane thanks to the dedicated ramps.

# ¿ Feb 15, 2011 05:13

dexter: Jun 24, 2003

Cichlidae posted:

How many miles does $1.80 get you, and how much time does it save? How much would you be willing to pay, maximum? Do they have ETC (electronic toll collection), or is it done manually at a booth?

I don't have to take them anymore but depending on the day it saved me anywhere from 10 minutes to upwards of an hour. Congestion is essentially zero and the average speed is much higher than the regular lanes since it's completely separated.

The rate depends on the day because it fluctuates with the traffic volumes in the express lanes. It can range anywhere from $1.30 ($0.08/mi) to $8.00 ($0.50/mi). They cap it at $8.00 and close it to non-carpoolers since traffic volumes are too high to "sell any excess capacity" as they put it. They don't move the barrier much yet since the lanes are only about 40% complete.

There's no toll booths, it's all debited electronically with transponders in each vehicle. They automatically issue a citation if you're detected entering the lanes (there's overhead sensors everywhere someone could enter/exit the freeway) when they're closed to solo drivers.

The only monitoring is done by CHP officers watching the lanes of traffic at random metering spots as there's a light above each traffic lane indicating if a transponder was detected. It can't be automated because it's free and you don't need a transponder if you have another person in your car.

No one really uses them unless they commute in them every day. I'll be driving with someone and they won't even make an effort to enter the carpool lanes with four people in the car since they think it costs. They recently added signs that say "Carpools Free" but people still don't get it.

# ¿ Feb 16, 2011 08:22

dexter: Jun 24, 2003

Mandalay posted:

How often do you see enforcement? Just north of you in Orange County, I don't see much enforcement of carpool lane restrictions, and these are pretty standard things with two sets of double yellow lines separating them all the time. If anything, OC is easier to enforce.

All the time. They're either standing on the shoulder, hiding up on-ramps or just weaving through traffic about 15mph faster (probably 95mph) than everyone else.

# ¿ Feb 17, 2011 06:08

dexter: Jun 24, 2003

Jasper Tin Neck posted:

You're correct in that it isn't very effective if the pricing information is only received after the fact or once you're at the ramp. Ideally, you'd have real-time information about prices and some sort of forecast.

I don't know about those lanes but the Express Lanes in San Diego are variable on a per-mile basis (as you can enter/exit them at many spots.) The full length ranges from $0.50 up to $16 or so for 20 miles of barrier separated lanes but they're free if you're carpooling. It saves anywhere from 5 minutes to upwards of an hour when traffic is absolutely terrible.

# ¿ Jul 3, 2012 02:21

dexter: Jun 24, 2003

Cichlidae posted:

Alright, then. That is a crazy design. I get that there's not much room, what with the ocean being right there, but would it kill them to put up a concrete barrier, or even a curb?

How about this?

https://maps.google.com/maps?q=Sorr...246451052038466

I'd say average speed is between 70 and 80mph when you're heading down that hill.I don't know why Street View blurred that bicycle sign, but it says "on the shoulder."

# ¿ Aug 29, 2012 05:30

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# ¿ May 12, 2024 08:04

dexter: Jun 24, 2003

Cichlidae posted:

Cover the signs, measure the speed in the middle of a straight, noncongested stretch during off-peak hours. Measure again every 3 years or so. Ya know, in accordance with the MUTCD:

Note that it doesn't say "Maybe" or "Perhaps" or even "Should." It's right there: "SHALL." We ignore a SHALL, and that's grounds for a ton of lawsuits and loss of Federal funding.

We track 85th %ile speeds on every road EXCEPT freeways, and periodically re-check them on every road EXCEPT freeways, probably because someone in the past decided that it's easier to ignore the MUTCD this way. They're wrong, though; even if we take the speeds and just throw them out the window and stick with what's out there now, it's more defensible than not even sampling the speeds.

Edit: Hell, if anyone got a speeding ticket just about anywhere in Connecticut, provided they weren't going far over the 85th, they could probably get away with it on the grounds that (as far as I know) the vast majority of speed limits in the state are fiat.

How important is the 'cover the signs' part? They never do that here and in certain areas with ridiculously low speed limits run extremely visible traffic enforcement.

# ¿ Sep 20, 2012 05:22

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