Quorum .Special 17istrict ~~ ~~~r ~~ Development Guidelines 1 ~_ ~4 ~'. 1~esign Guidelines for ilZe Street p'ramewark INTERSECTION DESIGN S'TANI]ARDS: MINOR FOUR-tiVA~' xN~'E'125~'CTION PAVERS SAND BCASTEL]~CONCl2FfE' ~TR~~T LAMP [a7 1b0' O.C. LCCA7Ea 2'-6" FKOM B.O.C. .STREET I_A,1w1P WITH ATTAC[-~ ~SfOI' S[C~! & 5fREEf SiCNS BARt~IEEt-I=REE ACCESS @ CiJRB STREET' ~TRE~ Q 25 O:C. LOGS-fID 2'~" FROM B.O.C, WITH TREE CRATE 35 'FACE TQ FACE'QF CURB 2 7RAFFtC LANES 2 PARKING LANES '?5 'FACE TO FACE OP CURB 2 TRAFFIC fAt~+ES 25 RAD{lJ5 C IhfTERSEC7TON ~~ 20' TANGENT --- 70' CROSSWALK 2 'FROM EXT~lDH] FACE OF CUfiB ~~, ~a ^ In lieu of eliminating the oppariunity far a modern roundabout at #hxs location, RQW could be reserved to provide the necessary land for future construction. It is z~ecomz~nez~ded that future approval of a roundabout be provided only after additional docunnentatioz~ on operating characteristics is available Pram other locations. RAW should be reserved based on existing analysis of design requirements. Actual design would be based on design criteria available at the time of approval. ^ The projected volumes on Quorum Drive and Mildred Drive will effectively cause the roundabout to function as a "T" intersection, requiring Mildred Drive traffic to yield to the much higher volumes on Quorum Drive. ^ The operation of the modern roundabout will farce traffic on Quox-u Drive to yield to vehicles tluniz~g le£t onto Mildred Drive. ^ The predominant movements within the proposed roundabout would be "straight through" movements northbound and southbound an Quorum Drive. These m,ovemez~ts can be mast effectively accommodated without a roundabout. ^ There are currently very ~'ew operating modern roundabouts in tYAe United States. 1Vlast of the documentation of operating conditions camel from overseas (England, Burope~ Australia) were driving characteristics are significantly different than those found in the United Mates. ^ Roundal5outs present an unfriendly environment to pedestrians and are counterproductive to creating a pedestrian friendly environment. Rec rnrnendations Based on these conclusions, we offer the fallowing recommendations: ^ The construction of a modern roundabout on Quorum Drive in Addison will ultimately be the Decision of Town officials after the consideration of many factors. These recommendations address only the transportation related issues of the proposal. ^ It appears from available data that a modern roundabout could be constructed an Quarunn Drive to accommodate the projected volumes, I-Iowever~ ,due to the limited experience with modern roundabouts in 1•Torth America, and little or no experience with roundabouts with similar traftc characteristics as projected on Quorum eve, we do not recommend a roundabout at this location. The introduction of significantly different roadway characteristics in this segment ofthe roadway is not consistent with the Baal of providing consistent design standards along a particular roadway or roadway type. It would seem that amore appropriate place for roundabouts would be at the intersection oaf residential streets within the development (similar design characteristics) rather than on tl'ie arterial. The limited experience of roundabouts in the US would make the construction of a roundabout on Quonim Drive an experiment, rather that a design decision based an creating desirable operational characteristics. ~- Mildred Drive will remain a minor collector with relatively low volumes, especially west of Quorum 17rive. 1VIUDERN ROXINAABOUT~ There has laeen much written lately about modern roundabouts. 11~Iost of these articles have focused on "modern roundabouts" rather than traffic circles. Modern rouz~dabauts differ afxom traffic circles in their design and operational characteristics. The primary advantage presented for modern roundabouts is their ability to replace signalized intersections while achieving a reduction in delay and accidents. The disad~rar~tages of modern z~oundabauts and a~ee also presented in many of the articles. Several are specifically related to the proposed roundabout at Quorum ]]rive and Mildred Drive. These include operational characteristics when the Mizzor Street (Mildred Drive) has significantly less volume than the Major Street (Quorum Drive), In this case, the roundabout essentially operates as a "T "intersection. Modern roundabouts also present a less friendly pedestrian environment, require mare land, and are less familiar to U.S. drivers. CONCIrLTSION~ ANlI RECONIlI'IEN]~ATIONS Based on our analysis, the following conclusions have been drawn: ^ It appears from the literature presented that modern roundabouts carA function effectively both for low volume and high volume locations provided that they are designed to accommodate the projected volumes and traffic characteristics are conducive to this type of control. ^ The proposed roundabout, if approved should be considered a Pugh volume roundabout, designed accordingly, and. its design analytically developed and documented. Roundabout diameters in the range of 300 feet worxld be expected. ^ The success of the modern roundabout hinges an slower speeds and yield at entry. These will be an unexpected roadway characteristic to many drivers and may initially result in driver confusion and increased conflicts between vehicles. Other segments of Quorum 17rive do not have similar characteristics. ^ The roundabout is proposed to replace signalization of this intersection. The need to signalize the Quorum T]rive/ Mildred Drive intersection is yet undetez~xained. ^ The roundabout will negatively impact the ability to provide progression for vehicles along Quorum Dri~'e. ^ The development of alternative access routes for the South Quaruzn area. ^ Traff"ic management actions to protect neighborhoods fxarn "cut-tlxrough" ixa£c. These actions have been initiated in the ongoing eiozt to create and maintain an effective transportation system to serve the citizens of the Town. ~unruaLDx~'ve Quorum Drive is currently a narth/sauth four lane divided arterial located approximately one-quarter mile west of the Dallas North Tollway. The Town a£ Addison Thoroughfare plan designates Quorum Drive as a nxinar arterial. The roadway provides access to Belt Line Road, a six lane, eastlwest regional arterial, and the Dallas North Tollway, a six lane, controlled access tall facility serving narth/sauth travel needs for the area. Quorum Drive will provide access for adjacent pz'aperties along its route. currently, the majority of this praperiy is undeveloped, but medium and high density land uses are proposed far the area. These type uses are projected to generate traffic that will utilize all of the available capacity of Quon~m Drive. PROPOSED DEVELOPMENT The proposed development includes approximately 40 acres of residential development containing approximately 3,500 multi-family dwelling units and 3U0,000 square feet of retaiUaffice development. As part of the master planning e$'arts of the development, the construction of a modern rau~xdabaut at the intersection of Quorum Drive and Mildred Drive has been proposed. Tr~it~ Generafion Based on, trip generation rates for these type land uses, the development would generate approximately 33,00 vehicle trips per day. Of the daily trips, appraxirnately ten percent would occur during the P.M. peals lxour. Based on the preliminary site plan furnished by the developer, it is assumed that the xnajanity ofthe trips generated by the development would use Quorum Drive to access the area. The capacity of Quorum Drive is approximately 30,000 vehicles per day. The pxopased development and additional development potential in the area will generate demand to completely utilize this capacity. Therefore, all analysis concerning the zoundabaut should utilize the capacity of Quorum as the projected tra~ffio volume. 2 B~~T ~~+I~a~tl~~a~=°r. n P~,R$Oy$ Tn,"-.1~;SPOr~TNiltN GR47UP 4,Qt:1P?,h.Y Barton-aschman Associates. Ina. 585 Bak Line ROed, Suite 198 • Rallas. Texas 75244 • ;? ~4) 991.19D~ • Fax: (214) 499.9201 MEMORANDUM TO: Jahn Baumgartner Tawas of Addison FROM: Crary Jost DATL: December 1, 1994 UDJECT: Quorum Drive I~aundabout A zz~odern raundabaut has been proposed, as part afthe Addison Town Center development, for the intersection of Quorum Drive and Mildred Drive in the Town of Addison. The development i~xciudes mid-rise aparkments and retail and would be located an bath side of Quorum Drive between the railroad and Airpork Boulevard. The proposed roundabout would serve as the focal point of the development. This memorandum presents the findings and conclasions an evaluation, ofthe impact o£the proposed roundabout an the transportation system serving the area. BACT~GRO'C]'Nb Transportation has Iong been a high priority in the 'T'own of Addison. The town has initiated several efforts over the recent years to create an effective transportation system `T'hese efforts include the fallowing: ^ The development of a comprehensive program of intersection improvements to increase capacity and efficiency of the existing roadtivay system. ~ Izr,.pleax~entation of txa~xsportation management actions to preserve :roadway capacity ^ Ongoing traffic signal timing optimization to improve operational efficiency. # The development of the Addison Thoroughfare Plan. ^ The funding and design of the Arapaho road extension. 1 ^ PARSi~AES • L~,. 1 b 1 1. l 1~ L ,U V l~ G~ ' L t ~! 1 l L ~~~~ ~ ~~ . 1[ntersectipn of Residential Street with A4e~i•s -,,.-. ,.r,_s_ ..... ~, ~~: ~~~ 5treec lamp at I00' a.c- Red brick accents ~;;';:: ~`~ f~~ ole mounted 2'-6" Pram P =-,`_ , ~ 6.a.c. ar wall mounted Antique Krick ar - -~~ ~~ equivalent unit paving 3. _~,:~- 24' fire lane 5treec lamp with attached - : street sign and slap sign. ~;'~" ,~, ~. 25' radius at intersection ~' ~ '. 20' tangent with anrique `s`'~'~"'- ~ brick avin ar r ;. ~ ~ - - { ~ --.~.w~ ~~ Ls ~~~F~ 1 ~ .~.~- ~.. ~.~ c-a~h•; rt, wa. - .~` '~ ~ ,- - 10' crosswalk -- Z' from °' {' ` extended face of curh_ Concrete curb pad with -~.- "..:.~; _ _ ._~ ~ = red brick pavers step at beginning of ~ _ ~' ,.,. - mews .,~F ~~ `~~~:' Antique brick intersection ~,~x ~r: ~: ~w insert ornamental trees at 25' a.c. average with tree ~*~~ ~ rz ~~ Tree grate with two bol- i hi d , ~ l t t t grates w t n mews an ~~. _ f ar s co pro ec rees 5' x 5' tree wells on resi- ~~ ~~~ ~ ~,~;~,.•_ .._.~ , dential streets. ~-~~~~ l ~: R ,~ , r ~` ~ ~~ Placement of trees in mews should compliment -~~=~~=~~~~--••-- design of adjacent build- ings. 3.~ ~n'I'FRSI~CTI_QN_~F,5i6N. ~TA~1'!]~RDS v~ t- ~ ~~ c z ~~ y ~uvrurre Speciall7istrict ~1~~'~~rJ Developr~xent Guidelines "`. 1'~esign Guidelines for the Street Framework INTERS,ECTIpN DL~'SIGN STANDA,R,L]S: hfA,JQK 1G'Or1R-WAY INI'ERSECTI~N PAVERS SAND BLASTED CONCREYE STREET LAMP ~a 100' O.C. LOCATED 2'-b" FROIvi B.O.C. STREET LAMP 1NCfH ATTACHED STOP 5[CN, & STRE~f SIGNS r BARRIER FRFE ACCESS C CURB STREET ,71~ @ 25' O.G, LOC.ATLU 2'~" FROM B.O.C. WfTH TREE GRATE ~~~ "~ ~~. 40' FAC'~ x0 FACE Off' CURB 2 7RAFF[C LAt~tES 2 PARECING LAt~'ES ~- 26 'FACE 70 FACE OF CLUE - 2 TRAFE{C LANES ^-- 25' RADIUS @ ~TT~ 2Q' TANGBVC "IQ' CROSSWAL(C 2 ' FROM E7CTET~~ FACE O~ C~JRB 16` SQUARE J?AVER II~ISERT _~r ,. ~~ ~ 1lOrlll`tl Spectnll]iStrtGt ~~~~~~~ Deveioomerxt Guidelines ~ ~-~=' t- Design Guidelines for the Street .Frame work I, INTERSECTION DESIGN STAN,~]ARDS: TH14EE-WAY INTER$EC'TIQN WITH NECKDQWN fry "f~ - 1 ~ f..' .~fi~ - - SAND Bi.ASTEf~ CONCRETE 26 ' FACF TO FACE OF CURB 2 7R-AF~~[C LANES BARRIER FREE ACCESS @ CURB 57}2E~f LAMP WC!'H .,4T7AC:F-~ .. STOP SiCN & STREFf SK.TIS ~~$~3 •r„.~ -t ~,-- o ~. `,, ~;, -- - -,~ _- -- ~a C~OSStiuA~c . .- _ .- 2 : FROM IXTENDE~ FACE C-F CURB _ t _. .. 1 _... ~. ~ J ~; - ~ , - bF; 'rx ~o' r NC~M~ ~. .. . A >r ki~ ' ~~= "~ PA1fFJt5 ' FA[.E TO FACE OF CUR$ . 3~ ;: ''~ 2 TRAFFfC LANES • - 2 FARtCWG LANES, `` K r LAMP ]QB' p_C. - LOCATS~ 2'-6" FROM B.O.C. - p S7REET~ TREE G~ 25' O.C. - . LOCATED~~'-6" FROM B_O_C. W1TH TREE C.RA7~ +4' ,- 1)l ~ L