On Ramp Meters
#1
Posted 24 July 2012 - 08:30 AM
#2
Posted 24 July 2012 - 01:50 PM
Is there a schedule, like certain months of the year, that the freeway on-ramp meters are turned on? I'm specifically interested in the east-bound on-ramp going towards EDH off E Bidwell. The past month has been blissful without them in the afternoon, but I noticed they were back on yesterday at 530.
They run off the freeway speed sensors. If 50 is moving at full speed with moderate traffic they stay green. If traffic slows and/or increases they come on. The only other thing that knocks them off is if there is construction nearby and they have to disable them or the sensors.
#3
Posted 24 July 2012 - 04:04 PM
Interesting, I always assumed they were set by time, but it makes sense to trigger them based on traffic flow.They run off the freeway speed sensors. If 50 is moving at full speed with moderate traffic they stay green. If traffic slows and/or increases they come on. The only other thing that knocks them off is if there is construction nearby and they have to disable them or the sensors.
#4
Posted 24 July 2012 - 04:10 PM
I find it interesting that a traffic calming device makes you sick. I'm sure you enjoy the slow'n'go over the stop'n'go effect they have on traffic once you get on the freeway, but like most people, I presume you're focused on the immediate effect of having to stop rather than on the big picture of how traffic is flowing overall on the freeway.Is there a schedule, like certain months of the year, that the freeway on-ramp meters are turned on? I'm specifically interested in the east-bound on-ramp going towards EDH off E Bidwell. The past month has been blissful without them in the afternoon, but I noticed they were back on yesterday at 530.
#5
Posted 24 July 2012 - 08:46 PM
Thank you granto. I assumed that they were on during the periods of time the highway is anticipated to be the most congested....typical commute hours & nonholidays, specifically when summer break is over.They run off the freeway speed sensors. If 50 is moving at full speed with moderate traffic they stay green. If traffic slows and/or increases they come on. The only other thing that knocks them off is if there is construction nearby and they have to disable them or the sensors.
The traffic is not significantly heavier right now than 1 month ago. There are days when it is, but it never seems to be the same day. I'd say typically Friday is heaviest, but not always. Take today for example, the meter was on at 530, but the amount of traffic going eastbound was very, very light.
My observation has been that it doesn't make that much of a difference when the meter is on or off on how the traffic merges into the eastbound lanes at that onramp (and I'm taking this route at least twice a day so I feel very familiar with it). The majority of drivers are courteous and take their turn in the right order while merging.I find it interesting that a traffic calming device makes you sick. I'm sure you enjoy the slow'n'go over the stop'n'go effect they have on traffic once you get on the freeway, but like most people, I presume you're focused on the immediate effect of having to stop rather than on the big picture of how traffic is flowing overall on the freeway.
I actually prefer the keep moving/merging thinger.
#6
Posted 25 July 2012 - 08:14 AM
Don't forget that you are seeing traffic at a moment in time. The sensors are spaced every quarter mile and are constantly measuring traffic flow.The traffic is not significantly heavier right now than 1 month ago. There are days when it is, but it never seems to be the same day. I'd say typically Friday is heaviest, but not always. Take today for example, the meter was on at 530, but the amount of traffic going eastbound was very, very light.
Another interesting tidbit. If someone hits their brakes in moderate to heavy traffic, it takes 45 minutes for that kink to work out of the system (my aunt used to do traffic studies for Caltrans).
#7
Posted 01 August 2012 - 04:18 PM
I've observed the ripple effect of how one person slowing down in heavy traffic for whatever reason eventually creates a stop'n'go wave that travels backwards through traffic. It is interesting to watch freeway traffic on sped up video, you really can see the ebb & flow dynamics of the overall system. Anyone who thinks the metering at onramps doesn't have a positive effect on the dynamics of freeway congestion has their head buried in the sand. Is it a cure all? No, but it is a good bandaid. The only cure is to add more lanes to increase the capacity, or do something to decrease the number of cars at any time of day. I don't like Big Brother / Uncle Sam over-regulating businesses, but if large metropolises dictated staggered working hours for the general 9 to 5 M-F type workers, they could spread out the commuting demand over a larger timeline which would have a significant impact on commute time by reducing the volume of traffic demand during any given hour. Stop'n'go traffic fundamentally lowers gas mileage and increases air pollution.Don't forget that you are seeing traffic at a moment in time. The sensors are spaced every quarter mile and are constantly measuring traffic flow.
Another interesting tidbit. If someone hits their brakes in moderate to heavy traffic, it takes 45 minutes for that kink to work out of the system (my aunt used to do traffic studies for Caltrans).
#8
Posted 01 August 2012 - 06:45 PM
One off ramp that is having major challenges right now (not related to meters) is EDH Blvd between 5-6 pm. Traffic gets backed up to a standstill, before the Latrobe exit. The trouble seems to be merging onto EDH Blvd. I think the original plans to anticipate future traffic needs were faulty.
#9
Posted 01 August 2012 - 06:58 PM
#10
Posted 01 August 2012 - 07:26 PM
I still think that particular onramp /meter is tied to a period of time - i.e., turned off during summer break. If it was a timed thing, then the meter would be on during the am commute too since traffic is much heavier, and it's not on. Yet.
One off ramp that is having major challenges right now (not related to meters) is EDH Blvd between 5-6 pm. Traffic gets backed up to a standstill, before the Latrobe exit. The trouble seems to be merging onto EDH Blvd. I think the original plans to anticipate future traffic needs were faulty.
FWIW, I do not have my head buried in the sand. sorry. We have a difference of opinion. Surely one would have learned over the last several days worth of discussion here that we all have different opinions. it doesn't make yours, or mine superior, but just different.
The thing is... this isn't a matter of opinion. Metering lights either work or they don't. Just doing a Google search on "metering ramps studies" brings up several reports. One of interest is one done by the state of Minnesota... which performed a study by taking a period of time (6 weeks) and measuring impacts with all of their metering lights functioning... and then another period of time (6 weeks) with all of their metering lights off. The study showed that the metering lights improved travel times and safety. I am sure CalTrans has done their own studies as well with their engineers.
#11
Posted 07 August 2012 - 03:49 PM
#12
Posted 07 August 2012 - 04:22 PM
Perhaps the "science" behind metering isn't opinion, and is based upon "research"......however, I am still entitled to MY observations & opinions. Oh yeah, CalTrans....The state of California has pretty much lost my trust over the past 10 years or so.The thing is... this isn't a matter of opinion. Metering lights either work or they don't. Just doing a Google search on "metering ramps studies" brings up several reports. One of interest is one done by the state of Minnesota... which performed a study by taking a period of time (6 weeks) and measuring impacts with all of their metering lights functioning... and then another period of time (6 weeks) with all of their metering lights off. The study showed that the metering lights improved travel times and safety. I am sure CalTrans has done their own studies as well with their engineers.
Just last week, Friday, there was a big accident down towards Hazel, blocking the majority of the east bound traffic. It was a ghost town on the freeway heading to EDH. But the meter was still on!
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