Q.
The shutdown period has concluded. What will Mn/DOT do now?
Q. How long will the modifications remain in effect?
Q. Why not turn all the meters back on?
Q. How did Mn/DOT select the meters that will remain off?
Q. What happens after study results are presented to the Legislature?
Q. What does the future hold for ramp metering?
Q. Why is my ramp meter off (or on)?
Q. How many metered ramps are actually active during the day, I’ve seen
different numbers reported?
Q.
Why are meters flashing yellow when the mainline is stop and go?
Q.
How were metering rates selected? How is this going to be different than
before?
Q.
How will you measure the effect of the new plan?
Q.
How does Mn/DOT’s Traffic Management Center determine which rate a meter
runs at?
Q.
In some instances, I've seen congestion happening prior to the designated
hours of operation for the meters. Why can't you turn the meters on earlier
than 6:30 in the morning, or 3:30 in the afternoon?
Q.
What are the preliminary results of the study that were used to set the
new metering strategy?Q.
Is Mn/DOT going to stop putting in meters or HOV bypasses?
Q.
I’m a carpooler and my only advantage is the HOV ramp-meter bypass. With
the ramp meters off at some locations or operating at a less restrictive
rate, my advantage is practically gone. Was Carpooling considered in this
new strategy? Q.
Are the ramp meters on Highway 10 going to get turned on? Will meters
be installed on the new TH100? What does this do to plans of completing
the ramp metering system for the metro area?
Q.
What are the goals of the new metering system?
The Minnesota
Department of Transportation shutdown all 430 meters in the Minneapolis/St.
Paul area on Oct. 16, 2000. The shutdown was part of a legislative mandate
that required Mn/DOT to study the effectiveness of ramp meters. The meters
have remained off for the required six-week period. Data has been collected
and is being analyzed in preparation for presentation to the Legislature
by Feb. 1, 2001.
Q.
The shutdown period has concluded. What will Mn/DOT do now?
A. Based
on input received from technical and advisory committees, the consultant
team and preliminary data from the study, Transportation Commissioner
Elwyn Tinklenberg made a series of decisions to be implemented Friday
afternoon, Dec.8, 2000. With the changes, ramp meters will be on for a
shorter period of time during rush hours, meters will change more quickly
from red to green and several meters will remain off.
The hours
of ramp meter operation will be limited to 6:30 - 8:30 a.m. and 3:30 -
5:30 p.m. Although the meters can come on between these hours, ramp meters
are traffic activated and will come on only if certain congestion thresholds
are met. Prior to the shutdown, meters were operating 6:00 - 10:00 a.m.
and 2:30 - 7:30 p.m. Metering will range between 2 and 15 seconds per
vehicle, depending on conditions. These measures will be applied system
wide. During the morning hours, 60 of 273 operating meters will remain
off and 63 of 329 operational meters will remain off in the afternoon.
These ramp meters will flash yellow.
Q.
How long will the modifications remain in effect?
A. Mn/DOT
anticipates that the modifications will be in effect at least until the
ramp meter study is presented to the Legislature on Feb.1, 2001. During
this time the department and its consultant team will collect new data
generated by the system modifications. While it is difficult to project
how long these modifications will be in place, they are likely to be the
first in a series of modifications that will determine how ramp metering
evolves in the metro area.
Q.
Why not turn all the meters back on?
A. It
has become clear that an all or nothing approach is not the best. Mn/DOT
is seeking balance between safety, efficiency and public consensus. Preliminary
market research shows that 20 percent of commuters want the meters left
off. A small percentage wants the ramp meters on as before. However, the
majority of commuters, about 70 percent, want the ramp meters modified.
They want fewer meters, shorter operating hours and faster lights.
Q.
How did Mn/DOT select the meters that will remain off?
A. Data
collected before the meters were turned off and preliminary findings in
recent weeks indicate that some meters could remain off. The commissioner
made the decision based on expert third party advice and input from technical
experts, community leaders and others.
Meters
that will remain off during the modification period were selected on one
of four possible criteria:
- Ramp is low-volume,
experiencing less than 400 cars per hour.
- Ramp is extremely
high volume, making it difficult to manage effectively. An example is
northbound 35W to westbound 94 in Minneapolis.
- Ramp is atypical.
An example is Portland Avenue to eastbound Highway 62 where it is the
sole meter in the zone - it doesn't "fit" with the upstream or downstream
zones in the area.
- Ramp does not
operate often because congestion does not meet the minimum "turn on"
thresholds.
Q.
What happens after study results are presented to the Legislature?
A. The
commissioner will make that decision after the data from the study is
compiled and analyzed. This will include congestion delays, traffic speeds,
fatal and non-fatal crashes and public opinion research. The commissioner
will also consider information gained from modifications.
Q.
What does the future hold for ramp metering?
A. Mn/DOT
will continue to try to strike a balance between safety, efficiency and
public consensus. Changes may be made from time to time as the department
learns what impact modifications have on specific locations and system
wide.
Ramp
meters are not a long-term solution to congestion. In 1982, according
to the Texas Transportation Institute, the Twin Cities area was the 43rd
most congested region in the country. By 1997, the area had moved to 14th
or 19th, depending on the survey used. Projections indicate that congestion
continues to accelerate and the region continues to grow.
Policy-makers
need to look at long-term solutions that will require investments in roads
as well as more transportation choices.
Q.
Why is my ramp meter off (or on)?
A. The actual turn-on of meters is based on a set of complex mathematical
formulas called algorithms which take into account various congestion
level thresholds - including volume data (information on the numbers of
vehicles actually traveling through the system). These data are gathered
by 3700 loop detectors (sensors) located in the pavement throughout the
Metro area. These sensors are polled once every 30 seconds by a computer
at the Traffic Management Center which then automatically either activates
a meter, or determines it should remain in a flashing yellow mode.
Q.
How many metered ramps are actually active during the day, I’ve seen different
numbers reported.
A. System-wide there are 430 metered ramps. However, in the morning when
traffic is primarily "inbound" or moving suburb to suburb, a total of
213 ramps can be turned on. In the evening, when traffic is primarily
"outbound", a total of 266 metered ramps can be activated to flash green,
yellow, and red.
Q.
Why are meters flashing yellow when the mainline is stop and go?
A. During those hours when ramp meters can be activated (6:30 to 8:30
in the morning and 3:30 to 5:30 in the evening), they will do so based
on volume/congestion thresholds which when met trigger the start-up of
a meter. These thresholds are based on the number of vehicles entering
the freeway in a particular area (or zone) and the number of vehicles
already on the freeway in that same zone. (To help it better manage the
freeway network, Mn/DOT has divided it into 93 zones, each between three
and five miles long).
Under
the recently enacted ramp meter modifications, when a zone becomes so
congested that metering would no longer be helpful to the efficient movement
of traffic through it, the zones meters will simply continue to flash
yellow. If congestion thresholds in a specific zone are met prior to the
start of ramp meter operating hours, the meters in that zone will continue
to flash yellow throughout the rush hour.
Q.
How were metering rates selected? How is this going to be different than
before?
A. Prior to the ramp meter shutdown, and prior to the recently enacted
modifications, there were six different metering rates that could be applied
at any given meter, at any given time during the morning and evening rush
hour. The range of red times for each of those rates - excluding the 2-second
yellow/green time was:
Rate
1 = from 0.1 to 11.3 seconds
Rate 2 = from 0.1 to 13.4 seconds
Rate 3 = from 0.1 to 16.2 seconds
Rate 4 = from 0.1 to 18 seconds
Rate 5 = from 0.3 to 18 seconds
Rate 6 = from 0.6 to 18 seconds
The
modifications currently under study call for metering rates to be capped
at Rate 2.
Rate
1 = red time ranges from 0.1 to 11.3 seconds
Rate 2 = red time ranges from 0.1 to 13.4 seconds
Note: The actual
red time for a specific ramp is based on the number of vehicles that use
that ramp in a given hour. The higher the volume on the ramp the lower
the red time used for the ramp.
Mn/DOT's decision
to "cap" metering rates at rate 2 reflects input it received from numerous
sources, including daily rush-hour commuters, the consultant team working
on the study, the ramp meter shutdown study's Citizen's Advisory and Technical
Committees, and traffic management and engineering experts from within
the Department. It was clear, based on all that impact, that Mn/DOT's
ramp metering strategy and policy could not be the same as it was during
pre-shutdown conditions.
Q.
How will you measure the effect of the new plan?
A. Mn/DOT will continue to rely on outside expertise to help it develop
and implement technically sound ramp meter strategy, policy and modification
evaluation plans and to review and validate the results of those evaluations.
Travel time, safety, travel time reliability, throughput, and customer
satisfaction are among the measures of effectiveness expected to be regularly
monitored and tracked.
Q.
How does Mn/DOT’s Traffic Management Center determine which rate a meter
runs at?
A. Whether a meter runs at rate 1 or 2, and just how much "red-time" a
traveler will experience at any given meter during actual metered/operating
hours, is based on a variety of factors programmed into custom software
written for Mn/DOT's Traffic Management Centers computers. (see previous
questions regarding metering rates and why ramp meters turn-on or stay
in a flashing yellow mode). Generally, The actual red time for a specific
ramp is based on the number of vehicles that use that ramp in a given
hour. The higher the volume on the ramp the lower the red time used for
the ramp. .
Q.
In some instances, I've seen congestion happening prior to the designated
hours of operation for the meters. Why can't you turn the meters on earlier
than 6:30 in the morning, or 3:30 in the afternoon?
A.
During the course of this legislatively mandated study, it became clear
that an all or nothing approach is not the best. Market research showed
that 20 percent of commuters want the meters left off, roughly 10 percent
of commuters want the ramp meters on as before, and about 70 percent want
the ramp meters modified. (They want fewer meters, shorter operating hours
and faster lights). The current modifications are a first cut at finding
a balance between safety, system efficiency and public consensus. The
impacts of these modifications will be monitored, and adjustments made
as traffic patterns change and congestion levels continue to grow. For
now, hours that the meters can come on are 6:30 to 8:30 in the morning
and 3:30 to 5:30 in the evening.
Q.
What are the preliminary results of the study that were used to set the
new metering strategy?
A. Although the data has not yet been fully analyzed, certain trends were
apparent, and each - along with other input received from a variety of
sources and expertise from both in and outside of the Department - contributed
to the ramp meter modifications. These trends included the fact that traffic
operations improved in some places and degraded in others; accident rates
appearing to be up (the impact on the severity of accidents is not yet
known), and the majority of the public preferring a number of specific
ramp metering modifications - including having ramp meters on for shorter
periods of time during rush hours, less restrictive metering rates, and
fewer meters turned back on.
Q.
Is Mn/DOT going to stop putting in meters or HOV bypasses?
A. These are longer-range policy questions that cannot be addressed until
the results of the ramp meter shutdown study are completely analyzed and
presented to the Legislature for its consideration.
Q.
I’m a carpooler and my only advantage is the HOV ramp-meter bypass. With
the ramp meters off at some locations or operating at a less restrictive
rate, my advantage is practically gone. Was Carpooling considered in this
new strategy?
A. The impacts of ramp meters on mass transit and other HOV's (like carpoolers)
was one of the issues studied. Data regarding those impacts is presently
still not available - but will be in time for the report to the legislatively
mandated February 1, 2001 report. As part of its effort to balance both
the engineering perspectives along with the needs of multiple system user
groups like those who use transit or who carpool, the Agency will continue
to track ramp meter modification impacts and make those adjustments which
can technically and feasibly be made.
Q.
Are the ramp meters on Highway 10 going to get turned on? Will meters
be installed on the new TH100? What does this do to plans of completing
the ramp metering system for the metro area?
A. These are another set of longer-range policy questions that cannot
be addressed until the results of the ramp meter shutdown study are completely
analyzed and presented to the Legislature for its consideration.
Q.
What are the goals of the new metering system?
A. The goals of Mn/DOT's metering system
are to strike a balance between what is right and proper from an engineering
perspective concerning the efficiency of moving as much traffic during
the rush hours as possible, and the safety and other concerns of the people
who use the system everyday. This goal is complicated by the dynamic and
ever-shifting nature of traffic, and by the fact congestion is growing
at an annual rate of 3.5 percent. What that means is that even with ramp
metering, roadway congestion will continue to be a daily fact of life.
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