Answers to Frequently Asked Questions
FAQ
- Why Speed
Limits...?
- Roadside
Mailboxes ... ?
- Multi-way Stop
Signs ... ?
- Speed bumps ... ?
LAW
Prima facie speed limits are those which, "on the face of
it", are reasonable and prudent under normal conditions. A
driver may exceed any prima facie limit if it is safe to do so;
however, it is up to the driver to prove that he was driving in a
safe manner under the existing conditions.
In Colorado, basic prima facie speed limits are:
- 25 MPH in any business district
- 30 MPH in any residential district
- 20 MPH on narrow, winding mountain roads
- 40 MPH on open mountain traffic ways
Absolute speed limits are those which may not be legally
exceeded under any circumstances. These are:
- 75 MPH on rural interstate
By Colorado State Statue CRS-42-4-1101, speed limits are not to be
higher or lower than the basic lawful speed limits unless a
traffic investigation has justified the change. This law applies
to all State Highway, County Roads and City Streets.
Each investigation to determine an appropriate speed limit
should consider those factors applicable to the portion of road
being studied.
These factors are:
- Vehicle speed data (85th percentile)
- Roadside development
- Accident experience
- Road characteristics
- Hazardous locations (curves -- both horizontal and
vertical)
- Parking practices / pedestrian activity
The use of vehicle speed data as one of the factors evaluated
for selecting a suitable speed limit is based upon the following
fundamental concepts deeply rooted in the United States system of
government and law:
- Laws cannot be effectively enforced without the consent
and voluntary compliance of the public majority.
- Laws are established for the protection of the public and
the regulation of the unreasonable behavior of a few
individuals.
- The normally careful and competent actions of a
reasonable person should be considered legal.
- Most drivers are reasonable people who will drive
carefully at a speed which is suitable for the existing
conditions.
MISCONCEPTIONS
It is a popular misconception that reducing the speed limit
will automatically slow the speed of traffic, while raising the
speed limit will automatically cause an increase in the speed of
traffic.
Most "Before and After" speed studies show that
there are no significant changes in vehicle speeds after speed
limits are changed. "Before and After" accident studies
usually do no show any significant change accident rates after
speed limits are increased or decreased.
UNREALISTIC SPEED LIMITS
Traffic investigations have shown that most people will drive
the roadway conditions as they perceive them and will ignore a
speed limit that is unrealistically too low or too high. A
realistic speed limit is voluntarily obeyed by the reasonable
majority and more enforcement effort can be applied to the
unreasonable few who drive too fast of too slow.
An unrealistic speed limit that is "too low" will:
- Make the behavior of the majority unlawful
- If enforced - cause antagonism toward enforcement
personnel and traffic laws in general
- Create a bad image for the community with visitors and
tourists
- Result in speed differentials in the traffic flow
Reducing speed limits to an unrealistically low value does not
increase safety, but may create a "speed-trap". A
"speed trap" is a road segment where normal conditions
are adequate for a higher speed than the official speed limit
selected and where the enforcement activity is high.
A speed limit that is "too high" will be ignored by
the reasonable majority, but a few will dive too fast and create
speed differentials.
If conditions are adequate, high speed is not a significant
case of accidents, however it means increased stopping distance
and reduced reaction time. At higher speed the accidents that do
occur tend to cause more damage to persons and property.
REALISTIC SPEED LIMITS
An appropriate, "just right" speed limit will result
in the maximum number of vehicles traveling at about the same
speed, thus reducing conflicts caused by speed differentials. The
85th percentile speed, that speed at or below which 85% of the
traffic moving, is widely accepted as being closest to that
"just right" speed limit - A case of Majority Rule. Of
course, other traffic investigation factors must be taken into
consideration. The following are some reasons for establishing
realistic speed limits:
- To provide guidance to the driver, especially strangers
to the area, as to what is a suitable speed for normal
conditions
- Reasonable speed limits with adequate signing tend to
reduce the speed difference between vehicles. The
accident rate is less when the majority of vehicles are
at about the same speed.
- Furnished enforcement personnel with a guide as to what
is an appropriate speed for a segment of road so that
enforcement actions may be consistent and fair.
- Improves the overall credibility of all traffic control
devices.
WHAT YOU CAN DO
Anyone may report a road segment where the speed limit seems
to be too high or too low. If the segment is a portion of county
road or city street, contact should be with that county or
municipality. If the segment is a portion of the State Highway
system, including U.S. and interstate routes, contact should be
with the nearest office of the Colorado Division of
Transportation.
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Do you own a Roadside
Hazard?
Anything along side a street or highway that is a possible
source of damage or injury if struck by an errant vehicle is
considered a roadside hazard. Since nearly 50% of Colorado's
fatal traffic accidents involve vehicles that run off the road,
mailboxes designed to be aesthetically pleasing may be a
"hazard" waiting to be struck.
The design of a mailbox and its support have a direct
correlation to the damage / injury severity caused by vehicle
impact. Massive mailbox supports such as rock columns, plow
blades, railroad ties are potentially hazardous to the motorist.
Mailbox designs that are shown are approved by Postal authorities
and the Department of Transportation and are not considered to be
a hazard.
CANTILEVER MAILBOX SUPPORT
Supports that bend are desirable although 4" x 4"
wood post may be used, Boxes should be properly attached so as
not to become "missiles" if impacted.
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A stop sign can be one of our most valuable and
effective traffic control devices when used at the right place
and under the right conditions. It is intended to help drivers
and pedestrians at an intersection determine who should yield the
right-of-way.
MULTI-WAY STOP SIGNS
Well developed, nationally recognized guidelines help to
indicate when multi-way stop signs become necessary. The use of
"Multi-Way" stops (also known as "All-Way" or
"4-Way" stop sign installations) generally is
discouraged. However if the guidelines listed below are met
installation may be appropriate.
- Where traffic signals are warranted and urgently needed,
the multi-way stop is an interim measure that can be
installed quickly to control traffic while arrangements
are being made for the signal installations
- An accident problem exists, as indicated by five or more
reported accidents of a type susceptible to correction by
a multi-way stop sign installation in a 12-month period.
Such accidents include right and left turn collisions as
well as right angle collisions
- There must be certain minimum traffic volumes met
IMPROPER USES OF MULTI-WAY STOP SIGNS
Often multi-way stop signs are installed at locations where
they are not warranted. Misconceptions regarding the effects of
stop signs often lead individuals to request their installation.
Unfortunately pressure from misinformed but well-intentioned
individuals or groups can result in the unauthorized installation
of a multi-way stop. Improper use can create problems such as:
- Causing accidents
- Increasing speeds between intersections
- Unnecessary delays
- Breeding disrespect for all traffic control devices
- Increasing vehicle operating costs
- Increasing noise and air pollution
SAFETY PROBLEMS
Unfortunately stop signs are perceived by many as cure-alls
for traffic safety problems. Some people believe multi-way stops
will slow the speed of traffic or create such an inconvenience
that traffic will use other routes. Where stop signs are
installed as "nuisances" or "speed control
devices," there is an increase of intentional violations. In
addition, the speed reduction that is desired is effective only
in the immediate vicinity of the stop sign and often speeds
actually are higher between intersections.
FROM A LEGAL STANDPOINT
Most drivers are responsible and prudent. However, when
unreasonable traffic restrictions are imposed, increased
violations often occur. For example some drivers will make a
partial or rolling stop rather than a complete stop. Others may
tend not to obey the-right-of-way rule, especially if they
perceive that a stop sign is not appropriate at a particular
intersection. This often results in an increase of right-angle
accidents, the very type of accident the stop signs are installed
to prevent. In such cases, the stop signs can create a false
sense of security in a pedestrian and an attitude of contempt in
a motorist. These two attitudes will conflict with tragic
results.
REMEMBER
Because multi-way stop signs cause substantial delays, confuse
the motorist and can increase the risk of accidents they should
be installed only where the law and the Manual on Uniform Traffic
Control Devices allow.
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Speed bumps are not installed on Mesa County thoroughfares for
the following reasons:
- Our primary objective lies in maintaining the safest and
most efficient public roadway system possible. Drivers
expect these roads to be free of obstacles; barring
natural acts.
- The control of speeding in residential neighborhoods,
while maintaining acceptably safe street and roadway
conditions, is a wide spread concern which requires
persistent law enforcement effort. The inability of
posted speed limit signs to curb the intentional
violator, leads to frequent demands for installation of
"speed bumps" in public streets and alleys.
However, actual tests of experimental designs have
demonstrated the physical inability of a speed bump to
control all types of lightweight and heavyweight vehicles
successfully, In fact, a soft sprung sedan is encouraged
to increase speed for a better ride, while some vehicles
may lose control.
- Increased emergency vehicle response time.
- Cognate drivers braking for a speed bump may subject
themselves to a possible rear end collision with an
inattentive driver following too closely.
- Speed bumps inflict severe stress on vehicle suspension
parts. The possibility exists for vehicle damage and
subsequent loss of steering control, with catastrophic
results.
- Speed bumps pose a major maintenance problem particularly
on those roads routinely snow plowed during the winter
months.
- Increased hazard to the unwary; challenges to the
daredevils; disruption of the movement of both emergency
and service vehicles; and undesirable increase in noise,
have caused speed bumps to be officially rejected as a
standard traffic control device on public streets and
alleys.
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