ST9301A-CS 951005 MEMORANDUM
To: Jim Witt, City Manager ~
From: Kenneth M. Griffin, P.E., Assistant City Manager/City Engineer ~1
RE: Sandy Lake Road Bridge over the Elm Fork of the Trinity River
Bike Lanes (ST 93-01A)
Date: October 5, 1995
Attached to this memo is a letter from the consultant for Dallas County on the design of the
referenced bridge. There appears to be a problem with having a bike path along only one side of
the bridge. Originally consideration was given to moving the sidewalk from the south to the north
side and having bicycle traffic only on the south side and pedestrian traffic on the north side. The
problem with this approach is that on the south side of the bridge you would have eastbound bicycle
traffic, west bound bicycle traffic and eastbound vehicle traffic. This could potentially create a
dangerous situation for the westbound bicycle traffic when you are forcing it to travel in a direction
opposite the adjacent motor vehicle traffic.
Dallas County is constructing the full width six lane bridge and we will have the opportunity in the
foreseeable future to utilize the outside lanes for bike traffic on both sides. In essence, we will have
a sidewalk, a bike lane, and two lanes of traffic. This should serve our needs well into the neXt
century. The only time that there should be questions as to whether or not we need an additional
bike lane would be if Sandy Lake Road is widened from four to six lanes. As you are aware, we
have recently downgraded almost the entire section of Sandy Lake Road from six to four lanes. The
only sections that remain six lanes is from Freeport Pkwy. west to S.H. 121 and from MacArthur
Blvd. east to the city limits. It is safe to assume that when Sandy Lake Road is constructed and
there is additional development along Sandy Lake Road that there will be an increase in traffic.
However, it is very difficult to determine if the future needs will require a six lane road. Until such
time as a six lane road is required, there will be outside lanes on the bridge that could be used for
bicycles. If in the future the fifth and six lanes are needed and Sandy Lake is widened, then at that
time a bike lane could be constructed adjacent to and on the south side of the proposed 1100 foot
long bridge.
It is my opinion, that the City does not give up any rights or future opportunities by allowing the
bridge to be constructed as designed with the understanding that we could at a future date build a
separate bike lane if necessary. It is important to note that the decision to widen Sandy Lake from
four to six lanes rest entirely with the City of Coppell. If the City chooses not to widen Sandy
Lake, then we should always have the opportunity to utilize the fifth and six lanes as some type of
bike access across the Elm Fork of the Trinity River. I know that this issue has had substantial
conversation in the past, but it is time to make a final decision and move forward with the project.
The Dallas County Public Works Department and the Commissioners Court has expressed a concern
about this project and the City of Coppell's inability to either provide direction or give approval.
I will be available to discuss this with you at your convenience.
DALLAS COUNTY
uBuc wo xs · 5T 0'1
August 31, 1995
Mr. Ken Griffin, P.E.
City Engineer
City of Coppell
P.O. Box 478
255 Parkway
Coppell, Texas 75019
Re: Sandy Lake Project 91-838
(Coppell E. City Limits to Dallas City Limit)
Bicycle Lanes an~ Conference of August 14, 1995
Dear Mr. Griffin:
Attached you'find a copy of letter dated August 22, 1995 signed by
Lloyd James, P.E., Project Manager for Charles Gojer and
Associates. In this letter Mr. James takes issue with the area on
the bridge which is to be set aside for bicycles. Mr. James also
attaches sections of the AASHTO design guides as justification for
his concerns. Since you made the request for a bicycle lane we
request that' you review Mr. James letter and reply to Dallas
County, in writing, indicating your desires with respect to this
matter.
Additionally, please make reference to the minutes of the August
14, 1995 Coordination Conference (copy attached) held at this
office. Specifically refer to page two, Bridge Section, topic Cl.
Since your normal preference would be to utilize 4:1 slopes instead
of 3:1, slopes this is to advise you that we are formally
instructing the consultant to utilize 4:1 slopes throughout this
project. Also, please review the entire minutes carefully and
advise Dallas County in writing, of any topic that does not meet
with your understanding of the discussions.~
You may call me or Alberta Blair-Robinson at this office if you
have questions concerning the above or any other feature of the
above referenced project.
Sincerely,
Irvin S. Griffin, P. E.
Project Engineer ~
ISG/isg
~. Abel Saldana, P.E., Dallas County Project Engineer
Attachments: 8-22-95 Letter 8nd Attachment (7 pages)
Minutes & Sign In Sheet (6 pages)
Elm Street Dallas, Texas 75202 653-7151
Charles Gojer and Associates, Inc.
Consulting Engineers
Ci~ il and Slru( rural
August 22, 1995
Mr. Irvin S. Griffin, P.E.
Project Engineer
DALLAS COUNTY PUBLIC WORKS
411 Elm Street
Dallas, Texas 75202
RE: SANDY LAKE ROAD
Dear Mr. Griffin:
In the past we have discussed with you and the City of Coppell the issue of adding a bike lane on
the south side of the bridge. We have begun researching details associated with the development
of bike lanes and discovered that there is a problem with one bike lane only which forces bicycle
traffic to travel in a direction opposed to adjacent motor vehicle traffic. Reference the attached
excerpts from "Guide for Development of New Bicycle Facilities - 1981", published by the
American Association of State Highway and Transportation Officials".
It appears that if a separate bike lane is not provided on each side of the bridge as one-way
facilities to carry bicycle traffic in the same direction as adjacent motor vehicle traffic,
substantial adjusmaents must be made to the bridge width. Please consider this m_a__n_er and advise.
We will of course provide you with the technical details we have available. As you know,
additional bridge width will increase its cost and require additional time for plan revision.
Sincerely,
CHARLES GOJER AND ASSOCIATES, INC.
Lloyd L. James, P.E
Civil Engineering Manager -~,~ ~ ~ ~ ~ '~'~' ~t..:'ii!}
LLJPog .'-'-,~.::~ ;'~ ']'
enc.
~OUN~ DIRECTOR OE PUBLIG WORK?
11615 Forest Central Dr. ~204 ' Dallas, Texas 75243,/(214, 340-1199 / FAX ~214~ 348-8053
- GUIDE FOR
DEVELOPMENT OF
NEW BICYCLE
FACILITIES
1981
Approved by the Executive Committee on October 3, 1981
Published by the
American Association of State Highway
and Transportation Officials.
General Offices located at
444 North Capitol Street, N.W., Suite
225
Washington, D.C. 20001
Copyright, 1981, by the Amedcan Association of State Highway and Trans-
portation Officials. All Rights Reserved. Printed in the United States of
Amedca. The book or parts thereof, may not be reproduced in any form
without permission of the publishers.
use. This guide provides information on facilities. Information on other el-
ements or an overall bicycle program can be Found in other publications. Bicycle
The provisions for bicycle travel are consistent with and similar to stand- taken to de'.
ard highway engineering practices. Signs, signals, and markings for bicycle and lanes '~',
facilities which are presented in the Manual on Uniform Traffic Control travel needs
Devices (MUTCD) should be used in conjunction with this guide. State
pensive ant
and local specifications for the construction of roads and bridges are ap- highways, o'
plicable and should be consulted when constructing bicycle facilities pro- the base sys:
jeers, and lanes ct.
where accss
DEFINITIONS planning fo:
lives to pre
BICYCLE-A vehicle having two tandem wheels, propelled solely by Planning
human power, upon which any person or persons may ride. planning
BICYCLE FACILITIES--A general term denoting improvements and enhances bi.
provisions made by public agencies to accommodate or encourage bicyc- highway in-.
ling. including parking facilities, maps. all bikeways, and shared roadways enhance bic
not specifically designated for bicycle use. harmony
BICYCLE LANE (BIKE LANE)--A portion of a roadway which has
ments, whic
been designated by striping, signing and pavement markings for the The rifle-
preferential or exclusive use of bicyclists, be unders~:
BICYCLE PATH (BIKE PATH}--A bikeway physically separated from
In general.
motorized vehicular traffic by an open space or barrier and either within
utilitarian
the highway right-of-way or within an independent right-of-way.
BICYCLE ROUTE (BIKE ROUTE)- A segment of a system o[' bike- objective is
· The bicyc!e
ways designated by the jurisdiction having authority with appropriate ri-
hand, abic':
rectional and informational markers, with or without a specific bicycle is of little c-
route number.
BIKEWAY--Any road, path, or way which in some manner is specifi- purposes a:
cally designated as being open to bicycle travel, regardless of whether such have some
facilities are designated for the exclusive use ot' bicycles or are to be shared means of c-
with other transportation modes, cilities, the
HIGHWAY--A general term denoting a public way for purposes of anticipatec
vehicular travel, including the entire area within the right-of-way. Bicyclists
RIGHT-OF-WAY--A general term denoting land, property, or interest lng envirc7
and have ·
therein, usually in a strip, acquired for or devoted to transportation put-
will often -
poses.
. RIGHT OF WAY--The right of one vehicle or pedestrian to proceed in thetically
a lawful manner in preference to another vehicle or pedestrian, and result
ROADWAY-The portion of the highway, including shoulders, for importanc:
to fide or, -
vehicle use.
SHARED ROADWAY-Any roadway upon which a bicycle lane is not to unders:.
designated and which may be legally used by bicycles regardless of will usuai:
whether such facility is specifically designated as a bikeway, exclusive!:
SIDEWALK--The portion of a highway designed for preferential or Rather,
exclusive use by pedestrians, a broad
2
Traffic Control Devices many cases
At intersections where bicycle traffic exists or is anticipated, bicycles change lane~_
should be considered in the timing of the traffic signal cycle, as well as the Also, mo:
traffic detection device. Normally, a bicyclist can cross an intersection from drive,,_
under the same signal phasing arrangement as motor vehicles; however, width of 14 :'
on multi-lane streets special consideration should be given to ensure that ment width
short clearance intervals are not used. If necessary, an all-red clearance in- line to fane
tervai may be used. parking, and
_ To check the clearance interval, a bicyclist's speed of 10 mph (16kin/h) Widths grea:
and a perception/reaction/braking time of 2.$ seconds should be used. tion oftwo ."'
Detectors for traffic-actuated signals should be sensitive to bicycles and sideration si:
should be located in the bicyclist's expected path, including left turn lanes, exist.
Where programmed visibility signal heads are used, they should be
checked to ensure that they are visible to bicyclists who are properly posi-
tioned on the road. It may be _-
routes. Who-
The MUTCD should be consulted for guidance on signs and pavement
route can be
markings. Where bicyclists are expected to use different routings than mo-
torists, directional signing should be used to confirm to bicyclists that the long. For [or
special routing leads to their destination, merical des!~
in place of a
· Shoulders highway, in,:
;' is often des::
t. Wide curb lanes and bicycle lanes are usually preferred over shoulders markers to f_
for use by bicyclists. However, if it is intended that bicyclists ride on
route and ir.'
shoulders, smooth paved shoulder surfaces must be provided. Pavement
route signir,~
edge lines supplement surface texture in delineating the shoulder from the list around :-
motor vehicle lanes. Rumble strips can be a deterrent to bicycling on Overall. t:-
shoulders and their benefits should be weighed against the probability that on the advis_
.r bicyclists will ride in the motor vehicle lanes to avoid them. of on paraile
Shoulder width should be a minimum of 4 feet (1.2m) when intended to tots such ~
accommodate bicycle travel. Roads with shoulders less than 4 feet (l.2m) grade; and
wide normally should not be signed as bikeways. If motor vehicle speeds feasibility of
to a less dire
· :': exceed 35 mph (55km/h), if the percentage of trucks, buses, and recrea- inconvenier..
.~ tional vehicles is high, or if static obstructions exist at the right side, then
'~ additional width is desirable, drainage gr~
schedules, ar
~ Adding or improving shoulders can often be the best way to accommo- before a roa_
~ date bicyclists in rural areas, and they are also a benefit to motor vehicle
~ traffic. Where funding is limited, adding or improving shoulders on uphill Further g_
: sections first will give slow moving bicyclists needed maneuvering space
' and deCrease conflicts with faster moving motor vehicle traffic.
Bicycle
Wide Curb Lanes ble road spa:
vide for mo:
· : On highway sections without bicycle lanes, a right lane wider than 12 increase a bi.
.; feet (3.7m) can better accommodate both bicycles and motor vehicles in of travel. Li-
-~ the same lane and thus is beneficial to both bicyclists and motorists. [n out of their
:"
many cruses where there is a wide curb Jane. motorists ~,l[I not need to
:~,lt-'_d. bicycles' change lanes to pass a bic¥1ist.
:. ils well is the Also, more m~neuverin~ room is provided when dr:ve~s ar~ exiting
from driveways or in are~ with limited sight distance. In ~ener~l, a lane
Jm intersection
width or t4 ~t (4.~m) o~ us~bl~ p~v~m~nt width is d~sir~d. L's~bl~ p~v~-
:x~c~es: however,
:~ ~o ~nsur~ th~L m~nt width would normally be from curb [uce to lane stripe, or ~rom edge
-cd ~e~r~nce in- line ~o I~ne strip~, bu~ Adjustments need ~o
p~rkin~, ~nd longitudinal ridges between p~v~ment ~nd ~u~er sections.
~ mph (J6km/h) Widths ~r~t~r th~n J4 ~( (4.]m~ c~n encourage the undesirable oper~-
~houtd be used. Lion or two moLor vehicles in one lane, especially in urban ~re~. ~nd con-
= ~o bicycles and sideration should be given to stripin~ ~ ~ bicycle I~ne when wider widths
~,~ lel'L turn J~nes. ~xJst.
~hey should be Bicycle Routes
~r~ prop~rJy posi- I~ may b~ advanJa~o~s ~o sign som~ urban and rural roadways ~ b~cycle
rouJes. W~en providin~ ~oncinui~y to o~her bicycle facilities, a bicycl~
~s and pavement route can be relatively short. However, a bicycle tou~ng route can be quite
-g~tings than mo- lon~. For long bicycle routes, a standard bicycle route marker with a nu-
~c'~clists that the met/cai designation [n accordance with Part [X of the >IL'TCD can b~ used
in place o~a bicycle route sign. Th~ number may corr~spon~ to a parallel
highway, indicatin~ the route is a preferred alt~rnat~ route for bicyclists.
is often desirable to use supplemental plaques with bicycl~ route signs
-~,j over shoulde~ marke~ to furnish additional information, such ~ direction changes in the
~icyciists dale on route ~d intermediate range distance and destination information. Bicycle
-:vialed. Pavement route signing should not end at a barrier, information directing th~ bicyc-
s~ouId~r from the list around the barrier should be provided.
~'. to ~icyc[Jng on Overall, the decision whether to provide a bicycle routs should be b~ed
· -= probability that on the advisability of encouraging bicycle use on a particular road, instead
?.~m. of on parallel and adjacent highways. The roadway w~dth, alon~ with fac-
to~ such ~ the volume, speed, and type of tra~c; parking conditions;
, ,.~h~n intended to
grade; and sight distance should be considered when dete~ining the
:~an ~ feet (l.2m) legibility of a bicycle route. Generally, bicycle tra~c cannot be diverted
::or v~hicle spee~
to a le~ direct ~temate route unless the favorable facto~ outwei~ the
~uses, and recrea-
inconvenience to the bicyclist. Roadway improvements, such ~ s~e
:b,e right side, th~
d~nage grates, railroad crossing, smooth pavements, maJnten~ce
~hedul~, ~d signals responsive to bicycles, should always be considered
>: '~ay to accommo- before a roadway is identiHed ~ a bicycle route.
:~ to motor vehicle
Further guidance on signing bicycle routes Js provided in the >IUTCD.
~oulde~ on uphill ,
maneuvedn~ space Bic~'cle Lanes
:~ tra~c. Bicycle l~es c~ be co~idered when it is desirabl~ to delineate availa-
' hie road space for preferential ~e by bicyclism ~d motorist, and to pro-
~de for more predictable movemen~ by each. Bicycle I~e markin~ can
tan~ wider th~ 12 incte~e a bicyclist's conHdence in motorists not straying into his/her path
~ motor vehicles in of travel. Likewise, p~sin~ motoris~ are less lik~ly to swede to the left
:s and motorist. ~ out of their l~e to avoid bicyclis~ on their right.
I1
Bicycle lanes should always be one-way facilities and carry traffic in the
same'direcuon as adjacent motor vehicle trallic. Two-way bicycle lanes on
one side of the roadway are unacceptable because they promote riding
against the [low of motor vehicle traffic. Wrong-way riding is a major cause
of bicycle accidents and violates the Rules of the Road stated in the Uni- ~ ......
form Vehicle Code. Bicycle lanes on one-way streets should be on the right
side of the street, except in areas where a bicycle lane on the left will de- ! s'
crease the number of conflicts (e.g., those caused by heavy bus traffic). _ 8'-10' [ (mtn;
Under ideal conditions, minimum bicycle lane width is 4 feet ll.2m). ~,ki,g 8;k, ~.:-
However. certain edge conditions dictate additional desirable bicycle lane
width. To examine the width requirements for bicycle lanes. Figure 1
shows three usual locations for such facilities in relation to the roadway.
Figure 1 (a) depicts bicycle lanes on an urban curbed street ~,~here a parking
lane is provided. The minimum bicycle lane width for this location is $ feet (~'
(1.Sm). Bicycle lanes should always be placed between the parking lane
and the motor vehicle lanes. Bicycle lanes between the curb and the park-
ing lane create hazards for bicyclists from opening car doors and poor
visibility at intersections and driveways, and they prohibit bicyclists from L
making left turns: therefore this placement should never be considered.
Where parking is permitted but a parking lane is not provided, the com- ,
· ,. bination lane, intended for both motor vehicle parking and bicycle use.
should be a minimum of 12 feet (3.7m) wide. However, if it is likeiy the
combination lane will be used as an additional motor vehicle lane. it is
preferable to designate separate parking and bicycle lanes as shown in
Figure 1 (a). In both instances, if parking volume is substantial or turnover
is high, an additional I or 2 feet (0.3 or 0.6m) of width is desirable for safe (C) STRE:
bicycle operation.
Figure 1 (b) depicts bicycle lanes along the outer portions of an urban
curbed street where parking is prohibited. Bicyclists do not generall.v ride
near a curb because of the possibility of debris, of hitting a pedal on the
curb, of an uneven longitudinal joint, or of a steeper cross-slope. Bicycle
lanes in this location should have a minimum width of 5 feet (1.5m) from
the curb face. If the longitudinal joint between the gutter pan and the road- " ,'
i~ way surface is uneven and falls within $ feet (1.Sm) of the curb face. a ~i~,, _
.), minimum of 4 feet (1.2m) should be provided between the joint and the
CNot to Scale)
~;§ motor vehicle lanes.
·: Figure 1 (c) depicts bicycle lanes on a highway without curb or gutter.
Bicycle lanes should be located between the motor vehicle lanes and the
roadway shoulders. Bicycle lanes may have a minimum width of 4 feet
(l.2m). where the shoulder can provide additional maneuvering width. A
· :! width of 5 feet ( 1.5m) or greater is preferable: additional widths are desira-
ble where substantial truck traffic is present, where prevailing winds are a
,j factor, on grades, or where motor vehicle speeds exceed 35 mph ($Skm/ Figu
Bicycle lanes tend to complicate both bicycle and motor vehicle turning
"':i movements at intersections. Because they encourage bicyclists to keep to
bicycle paths and those for highways (e.g., in determining horizontal align-
ment, sight distance requirements, signing, and markings). On the other
hand, some criteria (e.g., horizontal and vertical clearance requirements,
grades, and pavement structure) are dictated by operating characteristics
of bicycles that are substantially different from those of motor vehicles.
The designer should always be conscious of the similarities and the differ-
ences between bicycles and motor vehicles and of how these similarities
and differences influence the design of bicycle paths. The following sec-
tions provide guidance for designing a safe and functional bicycle path.
V~'idth and Clearance
The paved width and the operating width required for a bicycle path are
primary design considerations. Figure 3 depicts a bicycle path on a separ-
ated right-of-way. Under most conditions, a desirable minimum all paved ~;5~.~-
width for a two directional bicycle path is l0 feet (3m). In some instances, ',,g'- -~)'--y~[L" ?~""
however, a minimum of 8 feet (2.4m) can be adequate. This minimum ,,. ~..
should be used only where the following conditions prevail: (1) bicycle ~ ..k. :~'}~_,,~.:
traffic is expected to be Iow, even on peak days or during peak hours (2)
pedestrian use of the facility is not expected to be more than occasional, 'L.~' s'~ ~, ~... --~__.
(3) there will be good hori zontal and vertical alignment providing safe and
frequent passing opportunities, (4) the path will not be subjected to main- ~, .e_
tenance vehicle loading conditions that would cause pavement edge -.---
damage. Under certain conditions it may be necessary or desirable to in- ,,~ -
crease the width ora bicycle path to 12 feet (3.?m); for example, because
of substantial bicycle volume, probable shared use with joggers and other ~
pedestrians, use by large maintenance vehicles, steep grades and where bi-
cyclists will be likely to ride two abreast. .--.
The minimum width ora one directional bicycle path is 5 feet (1.Sm}. It 'O~e--way:
should be recognized, however, that one-way bicycle paths often will be T.~,o-';;a¥-~' v
used as two-wa.y facilities unless effective measures are taken to assure Metric
(Not :c ~:a~e.
one-way operation. Without such enforcement, it should be assumed that
bicycle paths will be used as two-way facilities and designed accordingly.
A minimum 2-foot (0.6m) width graded area should be maintained
adjacent to both sides of the pavement; however, 3 feet (0.gm) or more is
desirable to provide clearance from trees, poles, walls, fences, guardrails,
or their lateral obstructions. A wider graded area on either side of the bicy-
cle path can serve as a separate jogging path.
A wide separation between a bicycle path and an adjacent highway is de-
sirable to confirm to both the bicyclist and the motorist that the bicycle
path functions as an independent highway for bicycles. When this is not
possible and the distance between the edge of the roadway and the bicycle
path is less than $ feet (1 .Sm), a suitable physical divider, such as a fence,
dense shrubs or other barrier may be considered. Such dividers serve both
to prevent bicyclists from making unwanted movements between the path
16
DALLAS COUNTY
5T fl % o'1
August 31, 1995
Mr. Ken Griffin, P.E.
City Engineer
City of Coppell
P.O. Box 478
255 Parkway
Coppell, Texas 75019
Re: Sandy Lake Project 91-838
(Coppell E. city Limits to Dallas city Limit)
Bicycle Lanes and Conference of August 14, 1995
Dear Mr. Griffin:
Attached you find a copy of letter dated August 22, 1995 signed by
Lloyd James, P.E., Project Manager for Charles Gojer and
Associates. In this letter Mr. James takes issue with the area on
the bridge which is to be set aside for bicycles. Mr. James also
attaches sections of the AASHTO design guides as justification for
his concerns. Since you made the request for a bicycle lane we
request that you review Mr. James letter and reply to Dallas
County, in writing, indicating your desires with respect to this
matter.
Additionally, please make reference to the minutes of the August
14, 1995 Coordination Conference (copy attached) held at this
office. Specifically refer to page two, Bridge Section, topic Cl.
Since your normal preference would be to utilize 4:1 slopes instead
of 3:1, slopes this is to advise you that we are formally
instructing the consultant to utilize 4:1 slopes throughout this
project. Also, please review the entire minutes carefully and
advise Dallas County in writing, of any topic that does not meet
with your understanding of the discussions.
You may call me or Alberta Blair-Robinson at this office if you
have questions concerning the above or any other feature of the
above referenced project.
Sincerely,
Irvin S. Griffin, P. E.
Project Engineer ~
ISG/isg
~. Abel Saldana, P.E., Dallas County Project Engineer
Attachments: 8-22-95 Letter 8nd Attachment (7 pages)
Minutes & Sign In Sheet (6 pages) m~:mv:om~m.K~
411Elm Street Dallas, Texas75202 653-7151
Charles Gojer and Associates, Inc.
Consulting Engineers
Ci~. il anti Strut rural
August 22, 1995
Mr. Irvin S. Griffin, P.E.
Project Engineer
DALLAS COUNTY PUBLIC WORKS
411 Elm Street
Dallas, Texas 75202
RE: SANDY LAKE ROAD
Dear Mr. Griffin:
In the past we have discussed with you and the City of Coppell the issue of adding a bike lane on
the south side of the bridge. We have begun researching details associated with the development
of bike lanes and discovered that there is a problem with one bike lane only which forces bicycle
traffic to travel in a direction opposed to adjacent motor vehicle traffic. Reference the attached
excerpts from "Guide for Development of New Bicycle Facilities - 1981", published by the
American Association of State Highway and Transportation Officials".
It appears that if a separate bike lane is not provided on each side of the bridge as one-way
facilities to carry bicycle traffic in the same direction as adjacent motor vehicle traffic,
substantial adjustments must be made to the bridge width. Please consider this matter and advise.
We will of course provide you with the technical details we have available. As you know,
additional bridge width will increase its cost and require additional time for plan revision.
Sincerely,
CHARLES GOJER AND ASSOCIATES, INC.
Lloyd L. James, P.E
Civil Engineering Manager ~ C
LLJPog ' ~'" '~' '-'
enG.
:OUNTY DIRECTOR OF. FUBLIG
1161 g Forest CentraJ Dr. #204 /Dallas, Texas 75243 / f214~ 340-11 c)g//Fq× (214~ 34~-805~;
GUIDE FOR
DEVELOPMENT OF
NEW BICYCLE
FACILITIES
1981
Approved by the Executive Committee on October 3, 1981
Published by the
American Association of State Highway
and Transportation Officials.
General Offices located at
444 North Capitol Street, N.W., Suite
225
Washington, D.C. 20001
Copyright, 1981, by the Amedcan Association of State Highway and Trans-
portation Officials. All Rights Reserved. Pdnted in the United States of
Amedca. The book or parts thereof, may not be reproduced in any form
without permission of the publishers.
use. This guide provides information on facilities. Information on other el-
ements of an overall bicycle program can be found in other publications. Bicycle
The provisions for bicycle travel are consistent with and similar to stand- taken to de'.
ard highway engineering practices. Signs, signals, and markings for bicycle and lanes
facilities which are presented in the Manual on Uniform Traffic Control travel needs
Devices (MUTCD) should be used in conjunction with this guide. State pensive ant
and local specifications for the construction of roads and bridges are ap- highways, e:
plicable and should be consulted when constructing bicycle facilities pro- the base sys:
jects, and lanes ca
where
DEFINITIONS planning fei
lives to pre.
BICYCLE-A vehicle having two tandem wheels, propelled solely by Planning
human power, upon which any person or persons may ride. planning
BICYCLE FACILITIES--A general term denoting improvements and enhances bi,
provisions made by public agencies to accommodate or encourage bicyo highway irt.
ling, including parking facilities, maps, all bikeways, and shared roadways enhance bic'
not specifically designated for bicycle use. harmony v,
BICYCLE LANE (BIKE LANE)--A portion of a roadway which has merits, whic
been designated by striping, signing and pavement markings for the The diffe-
preferential or exclusive use of bicyclists, be understc
BICYCLE PATH (BIKE PATH)- A bikeway physically separated from
In general.
motorized vehicular tra~c by an open space or barrier and either within utilitarian
the highway right-of-way or within an independent right-of-way, objective is
BICYCLE ROUTE (BIKE ROUTE)-A segment of a system of bike-
The bicyc!e
ways designated by the jurisdiction having authority with appropriate ali- hand, abic:.
rectional and informational markers, with or without a specific bicycle is of little
route number, purposes a:
BIKEWAY--Any road, path, or way which in some manner is specifi-
cally designated as being open to bicycle travel, regardless of whether such have some
facilities are designated for the exclusive use of bicycles or are to be shared means of o-
' cilities, the
with other transportation modes, anticipatec
HIGHWAY--A general term denoting a public way for purposes of
vehicular travel, including the entire area within the right-of-way. Bicyclist_<
RIGHT-OF-WAY--A general term denoting land, proper~y, or interest lng envire=
and have
therein, usually in a strip, acquired for or devoted to transportation put-
will often
poses, theticallv
.. RIGHT OF WAY--The right of one vehicle or pedestrian to proceed in -
a lawful manner in preference to another vehicle or pedestrian, and result
ROADWAY--The portion of the highway, including shoulders, for importanc~
to ride on
vehicle use. to under~:_
SHARED ROADWAY-Any roadway upon which a bicycle lane is not
designated and which may be legally used by bicycles regardless of will usual:
exclusive!
whether such facility is specifically designated as a bikeway. Rather,
SIDEWALK--The portion of a highway designed for preferential or
a broad ra'
exclusive use by pedestrians.
2
Traffic Control Devices many cases
At intersections where bicycle traffic exists or is anticipated, bicycles change lane,~
should be considered in the timing of the traffic signal cycle, as well as the Also, mo:
traffic detection device. Normally, a bicyclist can cross an intersection from drive,~..
under the same signal phasing arrangement as motor vehicles; however, width of 14 f-
on multi-lane streets special consideration should be given to ensure that merit width
short clearance intervals are not used. If necessary, an all-red clearance in- line to lane s
terval may be used. parking, anc
To check the clearance interval, a bicyclist's speed of 1.0 mph (16km/h) Widths grea:
and a perception/reaction/braking time of 2.5 seconds should be used. lion of two .~
Detectors for traffic-actuated signals should be sensitive to bicycles and sideration s~
should be located in the bicyclist's expected path, including left turn lanes, exist.
Where programmed visibility signal heads are used, they should be
checked to ensure that they are visible to bicyclists who are properly posi- It may be:
tioned on the road. routes. Whe-
The MUTCD should be consulted for guidance on signs and pavement
route can be
markings. Where bicyclists are expected to use different routings than mo- long. For 1o~
torists, directional signing should be used to confirm to bicyclists that the merical desig
special routing leads to their destination, in place of a
Shoulders highway,
is often des:-
Wide curb lanes and bicycle lanes are usually preferred over shoulders markers to F_
for use by bicyclists. However, if it is intended that bicyclists ride on route and ir,:
shoulders, smooth paved shoulder surfaces must be provided. Pavement route signing
edge lines supplement surface texture in delineating the shoulder from the list around ::
motor vehicle lanes. Rumble strips can be a deterrent to bicycling on Overall,
shoulders and their benefits should be weighed against the probability that on the advis,
bicyclists will ride in the motor vehicle lanes to avoid them. of on paralle
tots such as
Shoulder width should be a minimum of 4 feet (1.2m) when intended to
accommodate bicycle travel. Roads with shoulders less than 4 feet (l.2m) grade; and s
wide normally should not be signed as bikeways. If motor vehicle speeds feasibility of
to a less dir~
exceed 35 mph (55kin/h), if the percentage of trucks, buses, and recrea-
inconvenier.~
tional vehicles is high, or if static obstructions exist at the right side, then
drainage gr~
additional width is desirable.
schedules, a:
Adding or improving shoulders can often be the best way to accommo- before a roaz
date bicyclists in rural areas, and they are also a benefit to motor vehicle
Further
traffic. Where funding is limited, adding or improving shoulders on uphill
sections first will give slow moving bicyclists needed maneuvering space
and decrease conflicts with faster moving motor vehicle traffic.
Bicycle
Wide Curb Lanes hie road spac
vide for
On highway sections without bicycle lanes, a right lane wider than 12 increase a b~
feet (3.7m) can better accommodate both bicycles and motor vehicles in of travel. Lil.
the same lane and thus is beneficial to both bicyclists and motorists. In out ol' their
10
many cases where there is a wide curb lane. motorists will not need to
:~at~.d. bicycles change lanes to pass a bicylist.
:. as well as the Also, more maneuvering room is provided when drt,,'ers are exiting
['rom driveways or in areas with limited sight distance. In ~eneraJ, ~ lane
~n igt~rS~ction
width of 14 get (4.3m) o[ usable pavement width is desired. Usable pave-
ment width would normally be from curb lzace to lane stripe, or from edge
:~ ~o ~nsure that
line to lane stripe, but adjustments need to be made for drmnage grates,
-2d c!e~rance m-
parking, and longitudinal ridges between pavement and gutter sections.
~ mph ~ t6km/h) Widths greater than 14 feet (4.3m) can encourage the undesirable opera-
tion of two motor vehicles in one lane, especially in urban ~re~. and con-
~ould be used.
-z [o bicycles and sideration should b~ given to striping as a bicycle lane when wider widths
:xist.
n~ left turn lanes.
they should be Bib,'cie Ro~tes
~r~ properly posi- It may be ~dvantaBeous to sign some urban and rural roadways as bicycl:
routes. When providing continuity to other bicycle facilities, a bicycle
zns and pavement route can be relatively short. However, a bicycle touring route can be quite
-nut,nBs than mo- long. For long bicycle routes, a standard bicycle route marker with a nu-
t,cyclists that the tactical designation in accordance with Part IX of the MUTCD can be used
in place of~ bicycle route sign. The number may correspond to ~ parallel
highway, indicating the route is a preferred alternate route for bicyclists. It
is often desirable to use supplemental plaques with bicycle route signs
-~d over shoulders markers to furnish additional information, such ~ direction chan~es in the
bicyclists ride on route ~nd intermediate range distance ~nd destination information. Bicycle
3~,ided. Pavement route signing should not end ~t a barrier. Information directing the bicyc-
shoulder from the list ~round the barrier should be provided.
nt to bicycling on Overall, the decision whether to provide a bicycle route should be b~ed
t n~ probability that on the advisability of encouraging bicycle use on ~ particular road, instead
them. of on parallel and ~djacent highways. The roadway width, along with
to~ such ~ the volume, speed, and type of trance parking conditions;
~ ,,hen ~ntended to
Brade~ and sight distance should be considered when determining the
t~an 4 feet (1.2m) legibility of a bic~cl~ route. Generally, bicycle tra~c c~nnot be diverted
773~ vehicl~ speeds to a less direct ~lternate route unless ~he favorable f~ctors outwei~ the
a uses, and
inconvenience ~o the bicyclist. Roadway improvements, such ~
the right side, th:n
dr~n~Be Brutes, railroad crossings, smooth pavements, maint~nanc~
schedules, ~d signals responsiv~ to bicycles, should always be considered
~: w~y to ~ccommo- before a roadway i~ identified ~ a bicycle route.
:7t to motor vehicle Further ~uidance on signing bicycle routes is provided in the MUTCD.
shoulders on uphill
maneuvering space Bicycle Lanes
cie traffic. Bicycle l~es c~ be considered when it is desirable to delineate availa-
ble road space for preferential use by bicyclists ~d motorists, and to pro-
vide for more predictable movemen~ by each. Bicycle l~e markin~ can
Iane wider than 12 incre~e a bicyclist's confidence in motorists not straying into his/her path
d motor vehicles in of travel. Likewise, p~sing motorism are less likely to swerve to the left
:s and moto~sts. ~ out of their lane to avoid bicyclism on their right.
I1
Bicycle lanes should always be one-way facilities and carry traffic in the
same direction as adjacent motor vehicle traffic. Two-way bicycle lanes on
one side of the roadway are unacceptable because they promote riding,
ag,ainst the flow of motor vehicle traffic. Wrong-way riding, is a major cause
of bicycle accidents and violates the Rules of the Road stated in the Uni- ~ ......
form Vehicle Code. Bicycle lanes on one-way streets should be on the rig,hr ! s'
side of the street, except in areas where a bicycle lane on the left will de- 8'-1o' .~ (minl
crease the number of conflicts (e.g., those caused by heavy bus traffic). : ~ ·
Under ideal conditions, minimum bicycle lane width is 4 feet (l.2m). P, rkimj Bike
However, certain edge conditions dictate additional desirable bicycle lane
width. To examine the width requirements for bicycle lanes. Figure 1
shows three usual locations for such facilities in relation to the roadway.
Figure l (a) depicts bicycle lanes on an urban curbed street where a parking
lane is provided. The minimum bicycle lane width for this location is 5 feet
(1.Sm}. Bicycle lanes should always be placed between the parking lane
and thc motor vehicle lanes. Bicycle lanes between the curb and the park-
ing lane create hazards for bicyclists from opening car doors and poor ~;
visibility at intersections and driveways, and they prohibit bicyclists from 1
making left turns: therefore this placement should never be considered. (mtn}
Where parking is permitted but a parking lane is not provided, the com-
bination lane, intended for both motor vehicle parking and bicycle use, U{min)-g
should be a minimum of 12 feet (3.7m1 wide. However, if it is likeiy the [~ike Lane
combination lane will be used as an additional motor vehicle lane. it is
preferable to designate separate parking and bicycle lanes as shown in
Figure 1 (a). In both instances, if parking volume is substantial or turnover
is high, an additional I or 2 feet (0.3 or 0.6mi of width is desirable for safe {C) ,STILE
bicycle operation.
Figure l{b) depicts bicycle lanes along the outer portions of an urban
curbed street ~'here parking is prohibited. Bicyclists do not generall? ride
near a curb because of the possibility of debris, of hitting a pedal on the
curb, of an uneven longitudinal joint, or of a steeper cross-slope. Bicycle
'
lanes in this location should have a minimum width of 5 feet (1.Sm) from ~ Shou;der i
the curb face. If the longitudinal joint between the gutter pan and the road- '~
way surface is uneven and hits within 5 feet (l.Sm) of the curb face, a 81ke
minimum of 4 feet (1.2m) should be provided between the joint and the
{Not to Scale)
motor vehicle lanes.
Figure 1 (c) depicts bicycle lanes on a highway without curb or gutter.
Bicycle lanes should be located between the motor vehicle lanes and the
road~'ay shoulders. Bicycle lanes may have a minimum width of 4 feet
(1.2m). where the shoulder can provide additional maneuvering a'idth..4,
width of 5 feet ( 1 .Sm ) or greater is preferable; additional widths are desira-
ble where substantial truck traffic is present, where prevailing winds are a Figu
factor, on grades, or where motor vehicle speeds exceed 35 mph (55kin/
h).
Bicycle lanes tend to complicate both bicycle and motor vehicle turning
movements at intersections. Because they encourage bicyclists to keep to
bicycle paths and those for highways (e.g., in determining horizontal align-
ment, sight distance requirements, signing, and markings). On the other
hand, some criteria (e.g., horizontal and vertical clearance requirements,
grades, and pavement structure) are dictated by operating characteristics
of bicycles that are substantially different from those of motor vehicles.
The designer should always be conscious of the similarities and the differ-
ences between bicycles and motor vehicles and of how these similarities
and differences influence the design of bicycle paths. The following sec-
tions provide guidance ['or designing a safe and functional bicycle path.
Width and Clearance
The paved width and the operating width required for a bicycle path are
primary design considerations. Figure 3 depicts a bicycle path on a separ-
ated right-of-way. Under most conditions, a desirable minimum all paved '"'"C~
width fora two directional bicycle path is l0 feet (3m). In some instances,
however, a minimum of 8 feet (2.4m) can be adequate. This minimum ..~.. ~ ,,.
should be used only where the following conditions prevail: (I) bicycle
traffic is expected to be low, even on peak days or during peak hours (2) '
pedestrian use of the l'acility is not expected to be more than occasional,
(3) the re will be good hori zontal and vertical alignment providing sa fe and
frequent passing opportunities, (4) the path will not be subjected to main-
tenance vehicle loading conditions that would cause pavement edge "-'-
damage. Under certain conditions it may be necessary or desirable to in-
crease the width of a bicycle path to 12 feet (3.7m); for example, because
of substantial bicycle volume, probable shared use with joggers and other
pedestrians, use by large maintenance vehicles, steep grades and where bi-
cyclists will be likely to ride two abreast. --.
The minimum width ora one directional bicycle path is 5 feet (l.5m). It 'O~e-wa¥: "' t.'
should be recognized, however, that one-way bicycle paths often will be %,,o-way: 5' '.'
Metric Conve~
used as two-way facilities unless effective measures are taken to assure
Ihot tm ~ale,
one-way operation. Without such enforcement, it should be assumed that
bicycle paths will be used as two-way facilities and designed accordingly.
A minimum 2-foot (0.6m) width graded area should be maintained
adjacent to both sides of the pavement; however, 3 feet (0.gm) or more is
desirable to provide clearance from trees, poles, walls, fences, guardrails,
or their lateral obstructions. A wider graded area on either side of the bicy-
cle path can serve as a separate jogging path.
A wide separation between a bicycle path and an adjacent highway is de-
sirable to confirm to both the bicyclist and the motorist that the bicycle
path functions as an independent highway for bicycles. When this is not
possible and the distance between the edge of the roadway and the bicycle
path is less than 5 feet (I .5m), a suitable physical divider, such as a fence,
dense shrubs or other barrier may be considered. Such dividers serve both
to pr6vent bicyclists from making unwanted movements between the path
16