Current through Register Vol. 28, No. 3, September 1, 2024
Support:
01
Temporary traffic barriers, including shifting portable or movable barriers,
are devices designed to help prevent penetration by vehicles while minimizing
injuries to vehicle occupants, and to protect workers, bicyclists, and
pedestrians.
02 The four primary
functions of temporary traffic barriers are:
A. To keep vehicular traffic from entering
work areas, such as excavations or material storage sites;
B. To separate workers, bicyclists, and
pedestrians from motor vehicle traffic;
C. To separate opposing directions of
vehicular traffic; and
D. To
separate vehicular traffic, bicyclists, and pedestrians from the work area such
as false work for bridges and other exposed objects.
Option:
03 Temporary traffic barriers may be used to
separate two-way vehicular traffic.
Guidance:
04 (DE Revision) Paragraph deleted.
Standard:
05 Temporary traffic barriers shall be
supplemented with standard delineation, pavement markings, or channelizing
devices for improved daytime and nighttime visibility if they are used to
channelize vehicular traffic. The delineation color shall match the applicable
pavement marking color.
Guidance:
05A
(DE Revision) Prior to installation, temporary Portland cement concrete traffic
barrier should be painted white on the side adjacent to traffic. If the
temporary Portland cement concrete traffic barrier is in place longer than one
year, the temporary Portland cement concrete traffic barrier should be painted
white on the side adjacent to traffic once per year until the barrier is no
longer needed and removed from the roadway.
Option:
05B (DE Revision) Temporary Portland cement
concrete traffic barrier manufactured with white cement may be used to
eliminate the need for painting the temporary Portland cement concrete traffic
barrier
Guidance:
05C (DE Revision) Temporary traffic barriers
should be cleaned once every three months while in place on the roadway unless
otherwise directed by DelDOT Traffic. Cleaning of the temporary traffic barrier
during winter months should be completed in a manner that does not create ice
on the roadway.
Standard:
05D (DE Revision) For enhanced conspicuity,
non-directional retroreflective panels (see Figure 6F-8) shall be 6-inch wide
and 12-inch high with rounded corners. The non-directional retroreflective
panel shall have fluorescent orange, prismatic retroreflective sheeting on both
sides.
05E (DE Revision) When used,
non-directional retroreflective panels shall be placed at 50-foot intervals.
The first panel shall be mounted within 10 feet of the leading edge of
barrier.
05F (DE Revision) The
non-directional retroreflective panels shall be attached to the temporary
traffic barrier in such a manner as to prevent accidental removal. Bolts or
epoxy-based adhesives shall be used.
06 Temporary traffic barriers, including
their end treatments, shall be crashworthy. In order to mitigate the effect of
striking the upstream end of a temporary traffic barrier, the end shall be
installed in accordance with AASHTO's "Roadside Design Guide" (see Section
1A.11) by flaring until the end is outside the acceptable clear zone or by
providing crashworthy end treatments.
06A (DE
Revision) Beginning January 1, 2016, temporary Portland cement concrete traffic
barrier shall be crashworthy in accordance with NCHRP 350 or latest edition of
the Manual for Assessing Safety Hardware (MASH), published by AASHTO.
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Option:
06B (DE Revision) Prior to January 1, 2016,
temporary Portland Cement concrete traffic barrier that is not crashworthy in
accordance with NCHRP 350 or the latest edition of MASH may be used on state
maintained roadways if it meets or exceeds all of the following criteria:
A. The barrier was manufactured prior to
October 1, 2002
B. The barrier is
constructed of Class A concrete (as defined in the DelDOT Standard
Specifications) and is adequately reinforced
C. Has a joint system that provides a
positive connection between adjacent segments that can transfer tension and
moment in a vertical plane across the joint.
Standard:
06C (DE Revision) If temporary Portland
Cement concrete traffic barrier that is not crashworthy as described in
Paragraph 6A is used, the Contractor shall certify, in writing, to the Engineer
and DelDOT Traffic prior to installation, that the barrier meets the above
three conditions in Paragraph 6C and the joint system provided has been tested
and found acceptable under NCHRP Report 230 test criteria.
06D (DE Revision) Temporary traffic barrier
shall be offset a minimum of 1 foot from the edge of traveled way.
Guidance:
06E (DE Revision) On state-maintained roads
with a posted or 85th percentile speed greater than 40 mph, the rate of taper
for the flare of a traffic barrier should be 17:1. If space constraints limit
the length of flare, a minimum taper rate of 11:1 should be used.
06F (DE Revision) When space permits, the
leading edge of the attenuator/barrier should have a lateral offset of at least
12 feet from the traveled way.
06G
(DE Revision) If unpinned barrier is used, a lateral offset of at least 5 feet
should be provided between the barrier and the work area. Consideration should
be given to pinning the barrier if work is performed within 5 feet of the
barrier.
06H (DE Revision) When
space permits, channelizing devices should be placed along the tangent section
of the traveled way for a distance equal to the buffer space measured from the
intersection of the barrier and the right-hand edge of the closed travel lane
(see Figure 6H-34).
Option:
07 Warning lights or steady-burn lamps may be
mounted on temporary traffic barrier installations.
Support:
08 Movable barriers are capable of being
repositioned laterally using a transfer vehicle that travels along the barrier.
Movable barriers enable short-term closures to be installed and removed on
long-term projects. Providing a barrier-protected work space for short-term
closures and providing unbalanced flow to accommodate changes in the direction
of peak-period traffic flows are two of the advantages of using movable
barriers.
09 Figure 6H-45 shows a
temporary reversible lane using movable barriers. The notable feature of the
movable barrier is that in both Phase A and Phase B, the lanes used by opposing
traffic are separated by a barrier.
10 Figure 6H-34 shows an exterior lane
closure using a temporary traffic barrier. Notes 7 though 9 address the option
of using a movable barrier. By using a movable barrier, the barrier can be
positioned to close the lane during the off-peak periods and can be relocated
to open the lane during peak periods to accommodate peak traffic flows. With
one pass of the transfer vehicle, the barrier can be moved out of the lane and
onto the shoulder. Furthermore, if so desired, with a second pass of the
transfer vehicle, the barrier could be moved to the roadside beyond the
shoulder.
11 (DE Revision) More
specific information on the use of temporary traffic barriers is contained in
Chapters 8 and 9 of AASHTO's "Roadside Design Guide" (see Section 1A.11) and
DelDOT's Design Guidance Memorandum No. 1-21.
