Chapter 10A. General
Section 10A.01 Introduction
Part 10 provides standards and guidelines
for the design, installation, and operation of traffic control devices
at grade crossings of highway traffic and light rail transit vehicles
to facilitate the reasonably safe, orderly, and integrated movement
of all traffic. The principles in Section
8A.01 are the same but, because light rail vehicles sometimes
operate along streets and highways in mixed traffic with automotive
vehicles, the traffic controls and associated standards and guidelines
for highway-light rail transit grade crossings presented in Part
10 can be different than those presented in Part
Light rail transit is a mode of metropolitan transportation
that employs light rail transit vehicles (commonly known as light
rail vehicles, streetcars, or trolleys) that operate on rails in
streets in mixed traffic, in semiexclusive rights-of-way, or in
exclusive rights-of-way. Grade crossings with light rail transit
can occur at intersections or at midblock locations, including public
and private driveways.
An initial educational campaign along with an ongoing
program to continue to educate new drivers is beneficial when introducing
light rail operations to an area and, hence, new traffic control
Light rail alignments can be grouped into one of
the following three types:
- Exclusive: A light rail transit right-of-way that is grade-separated
or protected by a fence or traffic barrier. Motor vehicles, pedestrians,
and bicycles are prohibited within the right-of-way. Subways and
aerial structures are included within this group. This type of
alignment does not have grade crossings and is not further addressed
in Part 10.
- Semiexclusive: A light rail transit alignment that is in a separate
right-of-way or along a street or railroad right-of-way where
motor vehicles, pedestrians, and bicycles have limited access
and cross at designated locations only.
- Mixed-Use: An alignment where light rail transit operates in
mixed traffic with all types of road users. This includes streets,
transit malls, and pedestrian malls where the right-of-way is
Where light rail transit and railroads use the same tracks or adjacent
tracks, the traffic control devices, systems, and practices for
highway-rail grade crossings described in Part 8 shall be used.
Section 8A.01 contains
a set of definitions, most of which also apply to Part 10.
Section 10A.02 Use
of Standard Devices, Systems, and Practices
Because of the large number of significant variables to be considered,
no single standard system of traffic control devices is universally
applicable for all highway-light rail transit grade crossings.
The appropriate traffic control system to be used at a highway-light
rail transit grade crossing should be determined by an engineering
study conducted by the transit or highway agency in cooperation
with other appropriate State and local organizations.
Traffic control devices, systems, and practices shall be consistent
with the design and application of the Standards contained herein.
The traffic control devices, systems, and practices
described herein shall be used at all highway-light rail transit
Before any new highway-light rail transit grade
crossing traffic control system is installed or modifications are
made to an existing system, approval shall be obtained from the
local agencies having statutory authority to grant such approval.
To stimulate effective responses from vehicle operators and pedestrians,
these devices, systems, and practices should use the five basic
considerations employed generally for traffic control devices and
described fully in Section
1A.02: design, placement, operation, maintenance, and uniformity.
Many other details of highway-light rail transit grade crossing
traffic control systems that are not set forth in Part 10 are contained
in the publications listed in Section
Section 10A.03 Uniform
All signs used in highway-light rail transit grade crossing traffic
control systems shall be retroreflectorized or illuminated as described
in Section 2A.08 to
show the same shape and similar color to an approaching road user
during both day and night.
No sign or signal shall be located in the center
of an undivided highway, except in a raised island.
Such signs or signals should be installed with a clearance of at
least 0.6 m (2 ft) from the outer edge of the raised island to the
nearest edge of the sign or signal, except as allowed in Section
Where the distance between tracks, measured along
the highway between the inside rails, exceeds 30 m (100 ft), additional
signs or other appropriate traffic control devices should be used.
Section 10A.04 Highway-Light
Rail Transit Grade Crossing Elimination
Because highway-light rail transit grade crossings are a potential
source of congestion, agencies should conduct engineering studies
to determine the cost and benefits of eliminating these crossings.
When a highway-light rail transit grade crossing is eliminated,
the traffic control devices for the crossing shall be removed.
If the existing traffic control devices at a multiple-track
highway-light rail transit grade crossing become improperly placed
or inaccurate because of the removal of some of the tracks, the
existing devices shall be relocated and/or modified.
Where a roadway is removed from a highway-light rail transit grade
crossing, the roadway approaches in the light rail transit right-of-way
should also be removed and appropriate signs should be placed at
the roadway end in accordance with Section
Where light rail transit is eliminated at a highway-light
rail transit grade crossing, the tracks should be removed or paved
Based on engineering judgment, the TRACKS OUT OF SERVICE (R8-9)
sign (see Figure 10C-2) may
be temporarily installed until the tracks are removed or paved over.
The length of time before the tracks will be removed or paved over
may be considered in making the decision as to whether to install
Section 10A.05 Temporary
Traffic Control Zones
Temporary traffic control planning provides for continuity of operations
(such as movement of traffic, pedestrians and bicycles, transit
operations, and access to property/utilities) when the normal function
of a roadway at a highway-light rail transit grade crossing is suspended
because of temporary traffic control operations.
Temporary traffic control operations on highways with highway-light
rail transit grade crossings shall be as outlined in Part
When a highway-light rail transit grade crossing
exists either within or in the vicinity of a temporary traffic control
zone, lane restrictions, flagging, or other operations shall not
be performed in a manner that would cause vehicles to stop on the
light rail transit tracks, unless a law enforcement officer or flagger
is provided at the highway-light rail transit grade crossing to
minimize the possibility of vehicles stopping on the tracks, even
if automatic warning devices are in place.
The agencies responsible for the operation of the light rail transit
and highway should be contacted when the initial planning begins
for any temporary traffic control zone that may directly or indirectly
influence the flow of traffic on mixed-use facilities where light
rail transit and road users operate. Responsible agencies, along
with others affected, such as emergency services and businesses,
should meet to plan appropriate traffic detours and the necessary
signing, marking, and flagging requirements for operations during
temporary traffic control activities. Consideration should be given
to the length of time that the grade crossing is to be closed, roadway
classification, type of vehicle and traffic affected, the time of
day, and the materials and techniques of repair.
Temporary traffic control operations should minimize
the inconvenience, delay, and crash potential to affected traffic.
Prior notice should be given to affected public or private parties,
emergency services, businesses, and road users before the free movement
of vehicles or light rail transit is infringed on or blocked.
Temporary traffic control activities should not
be permitted to extensively prolong the closing of a grade crossing.
The width, grade, alignment, and riding quality
of the highway surface at a light rail transit crossing should,
at a minimum, be restored to correspond with the quality of the
approaches to the highway-light rail transit grade crossing.
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