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Texas Highway Department
Texas Municipal League
Joint Committee Median Practices on Highway Routes on City Streets
TEXAS HIGHWAY DEPARTMENT TEXAS MUNICIPAL LEAGUE
JOINT COMMITTEE MEDIAN PRACTICES ON HIGHWAY ROUTES ON CITY STREETS
~Austin, Texas "Apri I , 1960
\
TEXAS HIGHWAY DEPARTMENT TEXAS MUNICIPAL LEAGUE
JOINT COMMITTEE MEDIAN PRACTICES ON HIGHWAY ROUTES ON CITY STREETS
Chairman Frank Frey, Urban Engineer, Texas Highway Department ,Austin
Vice Chairman Eugene Maier, Director, Department of Public Works, Houston
Secretary Paul R. Tutt, Supervising Designing Engineer, Texas Highway Department, Austin
Albert W. Rollins George Dieter Lynn Andrews C. J. Griggs Henry B. Nabers· R. W. Burr
C. W. Smith T. C. Collier W. E. Carmichael R. 0. Lytton G. A. Youngs J. F. Snyder
COMMITTEE MEMBERS
TEXAS MUNICIPAL LEAGUE
City Engineer Director of Public Works
City Manager City Manager City Manager
Director of Planning and Traffic
City of Arlington City of Waco City of San Antonio City of Wichita Fa lis City· of Abilene City of Lubbock
TEXAS HIGHWAY DEPARTMENT
District Engineer District Engineer District Engineer District Engineer District Engineer District Engineer
District 4 District 9 District 12 District 15 District 19 District 21
The following people have served on the committee during the course of its work:
F. M. Davis ~ormer District Engineer, Texas Highway Department, San Antonio Marvin Springf'r former Director of the Department of City Planning at Dallas Dick G. Pepin former City Manager at Odessa Drahn Jones former Director of Public Works a+ Corpus Christi Charles Spivey former Director of Planning at Lubbock.
Charles J. Keese, Charles Pinnell, Charley Wootan and others of the Texas Transportation Institute at Texas A and M College assisted the Committee in much of its work.
In addition to these, many of the Districts and Divisions, particularly the Planning Survey Division of the Texas Highway Department and many of the cities of Texas, have assisted the Committee in its work.
STEPHEN J. MATTHEWS Exrndwe D1rcctor
C. C. CRUTCHFIELD Fu·ld Crmsullant
WM. A.. OLSON ],rgnl Coumd
TEXAS MUNICIPAL LEAGUE An Association of Cities for Municipal Progress
TO TEXAS CITIES AND TOWNS
402 Vaughn Building Austin r, Texas GReenwood 6-6oo:;
During the past year and a half,the Texas Municipal League and the Texas Highway
Department have joined in a comprehensive study of practices on median dividers on high-
way routes through our cities and towns. It is noteworthy that it could be done at this
particular time when urbanization- and even metropolitanization- is so rampant, and
traffic problems are becoming more acute.
The League, through its representatives, endorses the findings set out in this report
and encourages all Texas cities and towns to follow the recommendations herein.
We are gratefu I to the League committee members for giving so generously of their
time and talents, and are appreciative of the Texas Highway Department and its staff for
providing the opportunity to study this important area. We trust that the success of this
report and the application of its recommendations will continue the cooperative spirit in
which many mutual problems have been solved.
~ Executive Director
Official Publication TEXAS TOWN & CITY • Member of the American Municipal Association
TO THE HIGHWAY COMMISSION
This report on median practices on highway routes on city streets is unusua I in that
it is the result of efforts of a joint committee composed of representatives of the Texas
Municipal League and the Texas Highway Department. The use of median dividers has been
a worrisome problem to both the Department and Texas cities. This committee was formed
in September, 1958 and has been studying and discussing this matter for more than eighteen
months.
I believe it is significant that a committee of this composition is in agreement. The
cooperatiol") of the League and the time and efforts contributed by the individual members
from the various cities are appreciated.
I endorse the findings set out in this report and believe it will furnish valuable
guidance to both Department and City personnel. The Department is publishing the report
and distribution will be made by both agencies.
D. C. Greer State Highway Engineer
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TEXAS HIGHWAY DEPARTMENT TEXAS MUNICIPAL LEAGUE
JOINT COMMITIEE MEDIAN PRACTICES ON HIGHWAY ROUTES ON CITY STREETS
Mr. S. J. Matthews Executive Director Texas Municipal League 402 Vaughn But I ding Austin, Texas
Mr. D. C. Greer State Highway Engineer State Highway Building Austin, Texas
Gentlemen:
This Committee was formed in September of 1958 through the joint efforts of the Texas Municipal League and the Texas Highway Department. We were asked to s~udy the use of median dividers on urban arteria I routes, these having been a source of some difference of opinion among the various governmental agencies and individua I citizens affected by them in various ways.
The Committee has made a detailed study of this subject and this report represents our findings and recommendations. Additional research Is still in progress and we feel that it should be continued. It is our belief that it will further substantiate the findings presented in this report.
This report is submitted in the hope that you will endorse it and that It will be given wide distribution to City and Highway Department personnel who will be able to use it In the planning and design of urban highway and street work.
Sincerely yours
WHY WAS THE COMMITTEE FORMED ?
General Feobler:r.J.. Statement
To study and make recommendations regarding design policies for medians
on highways in urban areas.
Specific Statement of the Problem
Since the application and design of medians on State Highway extensions
in urban areas is often a matter of controversy among the Texas Highway
Department1 local city officials and abutting businesses 1 it is desirable to
study the influence of median location and design on the safety and capa
city of an urban highway extension and the economic effect of medians on
abutting business and property owners. The results of the study would be
submitted by this committee to the State Highway Engineer and the Execu
tive Director of the Texas Municipal League with the recommendation that
theybe adopted for use on highways in urban areas and other urban arterial
streets.
"'\.7\That Is a Median ?
For the purpose of the work of the committee 1 a median is defined as any
traffic separator on a four or more lane road which is more positive than
the standard double stripe at standard spacing.
Classifications of Medians are tabulated on Page 19.
6
WHEN TO USE A MEDIAN
Over a period of time, median dividers have been constructed on numerous urban
arterial projects. Many agencies have been involved and little or no uniformity in the
design and application of medians has resulted. The following are \7\Tarran ts
intended to help standardize the use of medians. When these conditions exist in the design
of a new arterial street or when an existing arterial street is to be improved, a median
which forms a barrier that traffic will not cross intentionally should be included as a part
of the design.
1. The average daily traffic for the design year (usually 20 years in the future) is
9, 000 cars or more, regardless of the expected speeds; or
2. (a) Traffic volumes are su~h that a facility with four or more lanes are needed
for moving traffic. This determination based on the design standards of the
agency responsible for the development; and
(b) The speed which traffic is expected to move during the off:-peak periods is •
35 miles per hour or higher (speed determination should be based on design
operating speed values rather than posted values).
These conditions require a median wide enough to accommodate a lane for left
turning traffic at intersections.
There may be locations where these co11ditions are not satisfied but where a
median is desirable. These locations might be where there are a large number of points of
access to the artery, where it is necessary to control unsafe movements, where a large
number of pedestrians must cross the thoroughfare, where cross street traffic volumes are
unusually high or where one or more other undesirable conditions which might be cured or
partially cured by a median exist . These loc11tions should be studied carefully to deter-
mine if a median would materially improve the situation.
7
~:~~~=--:". - - -----~- - ----
RESUME ~
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FINDINGS & CONCLUSIONS /,/ ~ .
Change has been the byword of our nation's street and highway traffic
since the artificially created period of abatement during the World War 11. Our popula-
tion has Increased. People have moved from the rural communities to the cities. Many of
our cities have more than doubled in population and now cover many times the area which
they formerly occupied. Our automobile population in Texas is now more than three times
what It was in 1945.
These figures have been recounted many times in the past few years and it Is not
necessary to elaborate on them in thIs report. They do make one point very clear ,howeve&
The traffic problem now is not the traffic problem of 1945 and the methods of dealing with
this problem now are not the same methods that would have been satisfactory in 1945.
Dividing the street or highway so that the two opposing streams of moving vehicles
are separated from each other by an area now commonly called a Median has been
found to be one measure which, along with others, will assist in keeping traffic moving in
an orderly, efficient and safe manner. Like many of the measures necessary to keep traffic
moving,the median restricts some traffic movements, thereby causing indirection for some
traffic,but some restrictions are often a matter of public necessity. Owners and occupants
of property adjacent to it sometimes feel that a divided roadway is a detriment to the use
of their property, but, generally, the other improvements and increased traffic efficiency
which accompany the median more than offset any disadvantage, particularly to retail
business.
8
WHY PROVIDE A MEDIAN ? .
The median by itself is not a complete solution to the problem but, when properly
designed and used in conjunction with other improvements,lt can be expected to accom-
plish the following results:
1. The median provides an insulating area between opposing streams of moving
traffic which reduces the strain on drivers and usually results in a reduction in
the accident rate and particularly a reduction in head-on collisions.
2. The median provides protection and control of cross and turning traffic.
3. The median provides a refuge for pedestrians making it safer for them to cross a
a. wide street.
4. The median encourages efficient signing and signalization. More efficient
signing and signalization are possible when traffic movements are regulated
into orderly channels by the median and by other channelizing islands.
5. The median provides space for left turn storage at intersections. At inter-
sections the median should be wide enough to accommodate an added lane for
storing left turning vehicles. This left turn storage lane is one of the most
important benefits of a median. When such a lane is provided, the efficiency
and safety of the intersection is greatly improved. Left turning cars are sepa-
rated from straight through traffic so that they do not impede the flow of the
through traffic, thus increasing the capacity of the street. Also,vehicles wait-
ing to make a left turn are not in the path of the through traffic and are not
likely to be hit from the rear.
6. The median makes it possible for traffic to move smoothly and safely at higher
operating speeds.
9
1. The median provides ·an insulating area between opposing streams of moving
traffic which reduces the strain on drivers and usually results in a reduction in
the accident rate and particularly a reduction In head-on collisions.
10
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2. The median provides protection and control of cross and turning traffic.
11
3. The median provides a refuge for pedestrians making it safer for them to cross a
wfde street.
-----
12
4. The median encourages efficient signing and signalization. More efficient
signing and signalization are possible when traffic movements are regulated
into orderly channels by the median and by other channelizing islands.
13
MoNTGoMERY J \ lL WARD ~ t - ""~.. i I . . .···~ .__ ---------.:__-7.24 -2. l_~ i - ~r· ~~-~- 44 -- 6"-Jl::· t-6'
120'
----r:-~:!J~IXED TIME~l~. ~ ~=----- ,----= --,-~-~-""u.s'>::'.-.e'>\!.o_~ . _ '"2_Row SECTION A-A ROW~
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STUDY 3-1
-85%-24MPH
85%-24M.P.H.-TYPICAL EXAMPLE
OF WIDE MEDIAN INTERSECTION
WITH TURNING LANES
5. The median provides space for left turn storage at intersections. At Inter-
sections the median should be wide enough to accommodate an added lane for
storing left turning vehicles. This left turn storage lane is one of the most
important benefits of a median. When such a lane is provided, the efficiency
and safety of the intersection is greatly improved. Left turning cars are sepa-
rated from straight through traffic so that they do not Impede the flow of the
through traffic, thus increasing the capacity of the street. Also vehicles wait-
ing to make a left turn are not in the path of the through traffic and are not
likely to be hit from the rear. 14
6. The median makes it possible for traffic to move smoothly and safety at higher
operating speeds.
15
More Facts Spacing of Crossovers
In general, the median should have openings or crossovers at cross street inter-
sections. Where the space between cross streets is very long, it may be necessary to provide
intermediate openings. These should be spaced equally between cross streets to provide
equal service to adjacent property. These intermediate crossovers should not result in a
spacing of less than 360' between openings. Additional openings should not be permitted
for private or business entrances or exits. If these were permitted, the value of the median
would be seriously impared, permitting traffic movements which cannot be accommodated
in an orderly manner and reducing the safety and efficiency of the streets.
Medians on Existing Streets
When a road or street is being constructed on new location or when additional
right of way is being secured to expand an existing thoroughfare, the principles set forth in
this report should be followed. When the traffic demand is such that an improvement must
be made on an existing street on which sufficient right of way cannot be secured, it may be
necessary to accept a design which is an improvement but which is not as good as is need
ed. When this condition exist~ every effort should be made to provide the added left turn
lane at intersections. It may be possible to do this by eliminating parking for some dis
tance in advance of the intersection. It should be kept in mind by a II governmenta I
agencies and by all individuals involved that the alternative to improving an existing
thoroughfare to the point where it will satisfactorily accommodate traffic is usually the
construction of another facility on a new location. By improving the existing facility to
its maximum capabilities,the necessity for relocation will be delayed as long as possible.
It is also usually possible to expand the existing facility cheaper and more quickly than it
would be to develop a new location.
16
About Medians Non -Barrier Medians
In those cases where it is not possible, due to limited right of way or other con-
siderations, to construct the type of median recommended, it may be that a median of lesser
design should be considered. Median areas which are formed of a pavement which contrasts
in color and texture with the traveled lane but which do not provide a physical barrier
have been used with good results, and a low blister of asphalt may be suitable for some
situations. This type treatment is not recommended where the warrants for a barrier type
median are satisfied but it is recognized that there wi II be cases where a barrier median is
not practical. It is also possible that a non-barrier median would work well on traffic
arteries where volumes do not require a barrier median under the warrants set forth.
Regardless of the type of median used, the provision of left turn lanes at intersections is
very important.
Transition - Median to Non- Median Section
The transition from a pavement without a median to one with a median, particular-
ly the transition from a rural high speed two lane road to a divided road,has been found to
be an accident problem location in many instances. This part of the design should be
given careful consid!'lrations. If possible, the median should be introduced on the left
side of the approaching traffic in such a manner that approaching traffic is not required to
change direction unti I it is beside the median. It can then be guided into a curved tran
sition by the median.
- - - - -...... -
~ - - - - - -I Not to Scale I
17
THE WORK /
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O~)HE COMMITTEE--------
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The committee first conducted a rather intensive study of available information on
the subject of medians. A survey of the practices and policies of other States and Cities
was made. Much data were available but little was of a factual nature of the type needed
to establish a sound basis for design. This led to the development of two types of research.
The committee, with the aid of the Texas Transportation lnstltute,began an inventory
of medians in use in Texas at this time. This inventory included approximately sixty
median locations, each about one mile in length. The anlaysis of these studies provided
the committee with much of the factual data needed.
The second type of research was the Initiation of three very detailed "before" and
"after" studies on current median projects. The "before" studies on these have been com-
pleted but as yet the "after" studies have not been made due to the time required for con-
struction of the projects. These each included complete traffic and economic studies. The
committee feels that it Is justified In releasing this report at this time without the benefit
of the results of these studies because of the considerable amount of.data secured in the •
shorter studies, the urgent need for guidance In this field and the complete unanimity of
feeling among the committee members on the points covered. The committee does feel
that these studies should be completed and the results reported at the time of their
complerion.
18
CLASSIFICATION OF MEDIANS
Traversable Median - is one which consists of paint
stripes, buttons, an area of pavement of contrasting color or texture or a combination
of any of these. Its purpose should be obvious to the driver but it does not present a
physical barrier to traffic movements.
Deterring Median - is one which may incorporate any of the
features of a Traversable Median plus a minor physical barrier such as a rolled asphalt
curb, bars or corrugations, or ci mountable curb.
Barrier Median -is one which traffic will not cross intentionally.
It may be a barrier curb, a guard rail or some type of wall.
This report is the result of a considerable amount of
work by the committee and by the various agencies
assisting the committee. It is not possible to present
all of the information collected but it was felt that
the following examples serve to illustrate the find
ings and are representative of the material assem-
bled.
19
Example 1 ... .. This example is a comparison of traffic operations on facilities with different
median designs. Figure 11 illustrates a section of roadway designed with a narrow (4 foot)
median and Figure 12 shows a similar section which utilizes a wide median with turning
lanes. The average volume on each of these facilities is approximately 18,000 vehicles
per day. The accident collision diagrams shown on these examples illustrate how the
median can be expected to affect the safety of a facility. The example shown in Figure 11
has considerably more accidents than the one shown in Figure 12.
20
ffi NOTE
3 PROVIDING
i"'l GEOMETRIC LAYOUT I
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TYPICAL MEDIAN LAYOUT
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185%-41MP.~ TYPICAL EXAMPLE
OF NARROW MEDIAN
FIGURE 11
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COLLISION DIAGRAM OF ACCIDENTS
\~ 85%·37.5 M P.H-
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TYPICAL EXAMPLE OF
CRO.W.
MEDIAN WITH TURNING LANE
FIGURE 12 21
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FIXED-TIME SIGNAL I
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BARRIER CURB
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STUDY NO.4
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Example 2 ..... This example is similar to Example 1 with the exception that the average volumes
on the facilities are in the range of 21,000 to 27,000 vehicles per day. Figure 13 shows a
narrow median and Figure 14 indicates a wide median. A comparison of the accident
collision diagrams on these examples shows far fewer accidents where an adequate median
is provided.
22
GEOMETRIC LAYOUT AND
ROADSIDE DEVELOPMENT
TYPICAL MEDIAN LAYOUT
AND CROSS SECTION
COLLISION DIAGRAM OF ACCIDENTS
GEOMETRIC LAYOUT AND
ROADSIDE DEVELOPMENT
TYPICAL MEDIAN LAYOUT
AND CROSS SECTION
COLLISION DIAGRAM OF ACCIDENTS
TYPICAL EXAMPLE OF
NARROW MEDIAN
FIGURE 13
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TYPICAL EXAMPLE OF
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STUDY NO. 41
60' 60'
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STUDY NO. 42
WIDE MEDIAN WITH TURNING LANE
FIGURE 14 23
Example 3 ..... This example is similar to Example 1 with the exception that the volume on the
facilities is in the range of 33,000 to 37,000 vehicles per day. Figure 15 shows a narrow
median and Figure 16 shows a wide median. These examples show many more accidents
where a narrow four foot median is provided as compared with a wide median with left
turn lanes.
24
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Example 4 ..... This example iltustrates typical traffic operation on facilities which have similar
design but carry different volumes of traffic. A majority of the studies indicated that very
little operational difficulties were encountered when the volume was below 9,000 vehicles.
However, when daily traffic volumes exceeded this amount, serious accident and opera
t lonal problems became obvious. Figure 18 illustrates operation below 9,000 vehicles per
day and Figure 17 illustrates operation with volumes over 9,000 vehicles per day.
26
COLLISION DIAGRAM OF ACCIDENTS
GEOMETRIC LAYOUT AND
ROADSIDE DEVELOPMENT
TYPICAL MEDIAN LAYOUT
AND CROSS SECTION
COLLISION DIAGRAM OF ACCIDENTS
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TYPICAL EXAMPLE OF
NARROW MEDIAN
FIGURE 17
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STUDY NO. 41
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r <( a:: ~ I.J..I w
I o~c 3 I< :;! 2 w "I D " g , ~" ~ ~"
I rs~~<(g ~~i r ~ ~ ~ §~ §~ ~ ~
_J -i-------r 90' R.aw.
t= 68' BACK TO 8A 'I( OF VRB
64'-8" ASPHALT PAVEMENT
I t 230'
11-100' I
~: II' w. 6'-4" 12' 6' •• ]., "II' 12' 12' 4' 12'
I I I ~~LIGHTING ~TANDARD I I I CONC MEOIAN ~ T
I EACH END OF CONC MEDIAN~ .,. I PAINTED YELLOW t BEADED
_jJ ......___ 85%-40M.PH.
IHLdbJI ~~ - I
II IJ=- 11 ~· -~ n1 ~ - "
85%-38M.P.H.~
TYPICAL EXAMPLE OF
NARROW MEDIAN
FIGURE 18 27
STUDY NO. ll
Example 5 ..... This example illustrates typical operation on facilities which have no median or
traversable median designs. Figure 19 shows a typical no median study and Figure 20
shows a typical traversable median.
28
GEOMETRIC LAYOUT AND
RCADSIDE DEVELOPMENT
TYPICAL CROSS SECTION
GEOMETRIC LAYOUT AND
RCADSIDE DEVELOPMENT
RO.W.
10'
-B5%-36MRH
85%-36 M.P.H.-------..
120'
56' CROWN
44' ROBO. WOT.
12'
TYPICAL EXAMPLE OF
NO MEDIAN ARTERIAL
FIG.URE 19
,-----
= ~
10'
R.QW
STUDY NO. ZO
-------1 \____
--1 ~I
TYPICAL MEDIAN LAYOUT
AND CROSS SECTION
ROW
13'
120'
58' ROBO WDT
II' l if I // 1
14'
ROW I \..__ PAINTFO MEDIAN
~~ I~ ~L COLLISION DIAGRAM ~ ~ .-==:~========'--'===========~~~ '";;~~===:::{ OF ACCIDENTS ~ 9 71?. -"
~ 711 85%-36 MPH- 1/b-TYPICAL EXAMPLE
OF NARROW TRAVERSABLE MEDIAN
FIGURE 20 29
STUDY NO. 27
References A Policy on Geometric.Design of Rural Highways; Washington, D. C. ;American Associa
tion of State Highway Officials; 1954.
A Policy on Arterial Highways in Urban Areas; Washington, D. C.; American Association
of State Highway Officials; 1957.
Traffic Engineering Handbook; New Haven, Connecticut; Institute of Traffic Engineers;
1950.
30