When the Planning Department and

Transcription

1 Traffic Study fr a Z BY PANG HO, ROBERT N. GREEN, AND ABBAS BEHMANESH When the Planning Department and the Transprtatin and Public Wrks Department fr the City f Frt Wrth, Texas, were asked t cnduct a traffic study fr the prpsed expansin f the Frt Wrth Z, they faced three majr bstacles. First, trip generatin rates fr zs were nt available. Secnd, z parking rates were limited and varied frm ne surce t anther. Third, a recmmendatin had t be made amid a majr cntrversy between the Zlgical Assciatin, the Parks and Recreatin Department (prpnent f the expansin plan), and varius ppsitin grups that invlved neighbrhd rganizatins and even sme cuncil members. The purpse f this article is t demnstrate hw t develp trip generatin data and parking needs data fr a z. Backgrund The Frt Wrth Z is lcated n University Drive in the suthwest part f twn, apprximately a mile nrth f Texas Christian University and 2 miles suthwest f dwntwn. The z currently ccupies apprximately 40 acres inside Frest Park, a majr city park that ffers a variety f recreatinal facilities, such as a swimming pl, sccer field, baseball diamnd, picnic area, and pen space. The park is extremely ppular during the spring and summer mnths. The z is als surrunded by relatively wealthy neighbrhds and the prestigius Clnial Cuntry Club (see Figure 1). Based n admissin recrds, the z generated apprximately 750,000 visitrs in The z has tw entrances ne near the intersectinf University Drive and Clnial cility frm 40 acres t apprximately 100 Parkway that has a parking lt f 300 spaces, acres. The plan als calls fr the eliminaand anther further inside the park that has tin f the smaller parking lt near Univera parking lt with 410spaces. The z master sity Drive, while the secnd lt is t be plan calls fr an expansin f the present fa- expanded t 1,100parking spaces. As a result llonlfl L PRRK HLL OR H-30UJ UCKERY BLUO. HEJGHT FOREST PRRK ~ mq >1 COLONRL PKUY (2-LN) l-s - - \ u a PfRKNG LOT w ~:: ~&!!! Figure 1. Existing lcatin f Frt Wrth Z. 1) \\ \ TE JOURNAL. MARCH

2 f this expansin, mst existing recreatinal facilities and pen space wuld be eliminated. Study Objectives The bjectives f this study fllw: 1. T determine the extent f traffic impact ver the adjacent street netwrk and the surrunding neighbrhds. 2. T determine whether the prpsed 1,100 parking spaces wuld be adequate, and if nt, hw many spaces wuld be needed. Prblems Encuntered Because the z is a very unique land use, its trip generatin and parking characteristics may be very different frm ther land uses. Trip generatin and parking generatin rates fr zs are nt listed in TE s Trip Generatin r Parking Generatin. z T develp thse rates fr study, varius transprtatin research centers at majr universities and a number f zs f similar size were cntacted. Unfrtunately, the rates btained shwed a large range f variatin. As a result, it was decided t develp ur wn trip and parking data fr the Frt Wrth Z. We Step L Obtained past daily visitr recrds and visitr prjectins fr the design year frm the z and the cnsulting firm preparing the expansin plan. Past daily admissin recrds were carefully examined t identify the mnthly trend and a day-f-the-week trend. Figure 2 shws the mnthly trend indicating the peak mnths f the year. Figure 3 illustrates the daily attendance trend representative f an average week. Step 2. Cnducted aut ccupancy surveys at the z n Thursdays, Fridays, Saturdays, and Sundays. These days were chsen t help identify any difference in aut ccupancy rate between weekdays and weekends. Surveyrs at the parking lt entrances checked and tallied at L5-minute intervals the number f passengers and vehicles. The aut ccupancy rate was then btained by dividing the ttal number f passengers by the ttal number f vehicles. The survey result shwed that aut ccupancy rates vary frm weekdays t weekends, with a 3.1 ccupancy rate during the week and 3.7 n the weekend. Step 3. Cmputed trips generated fr each day by dividing the prjected daily number f visitrs by the aut ccupancy rate. 140 Step 4: Determined trips in and trips ut fr the peak perid, using the data btained frm the aut ccupancy survey. These trips were then translated int percentages and multiplied by the expected number f visitrs arriving n the peak day and during the peak hur trip generatin. Step 5. Perfrmed trip distributin and assignment with the added backgrund traffic and cnducted capacity analysis fr the selected intersectins. Parking Generatin T develp parking generatin data, the fllwing steps were taken: Step 1: Cnducted suwey at the entrances t bth parking lts, as well as bth entry pints t the park at Clnial Parkway. The license plate numbers f the vehicles entering and exiting frm the tw parking lts and the park were recrded during the z hurs Z traffic during the weekends frm nn 3 p.m. peaks and t believedthat with a reliable visitatin prjectin and accurate field surveys n aut ccupancy, we culd generate reasnable trip generatin and parking generatin data. Generating Mp Generatin Data T generate trip generatin data, the fllwing steps were taken: 0 N Ott Nu Dec Jan Feb Mar ftpr May Jun Jut Rug Sep Mnth Figure 2. Mnthly attendance: FY ste JOURNAL MARCH 1989

3 and tallied at 15-minuteintervals. The license plate check was later used t identify thrugh traffic and vehicles that had t turn away after finding n parking space. Step 2. The entering and exiting vehicle data, as well as the parked vehicle data (the accumulated differences between entering and exiting vehicles), were then pltted n a graph t determine parking accumulatin and peaking characteristics (see Figure 4). hicles data were pltted n a graph, as shwn in Figure 5. The figure als shws the existing limit (i.e., existing parking supply), maximum limit (including all vehicles parked illegally inside the park, such as n the grass median r lawn), and the prpsed legal limit (i.e., prpsed parking supply f 1,100 parking spaces). Vkitr attendance fr that particular day was btained frm the z and related t the number f vehicles parked that day. Based n these figures, the current 710 spaces is insufficient t meet the demand, as will be the prpsed 1,100 spaces. The z master plan calls fr an Step 4. T estimate parking needs at the varius levels f attendance, a parking factr was develped. by. dividing the number expansin f the present facility f parked vehicles during the peak hur (1,026)by the number f visitrs fr the same frm 40 acres t day (7,300). A parking factr f 0.14was bapprximately tained. This factr can be multiplied by any level f attendance t determine parking 100 acres. - needs. Step 3. Similar surveys were cnducted n the Sunday and Saturday during the spring Findings break hliday. This time nly the parked ve- The study revealed that additinal traffic des nt have a significant impact n the existing street netwrk and surrunding neighbrhds. This is mainly because z traffic peaks during the weekends and frm nn t 3 p.m. and therefre has little effect n the street system during the nrmal rush hur. Althugh parking is sufficient fr the weekdays, the study als revealed that a significant shrtage ccurred during the Pang H received a master s degree in transprtatin planning ji-m the University f Kmsas in 1982.At the time this article was written, he was an assciate tmnsprtatin planner with the City f Frt W5rthPlanning Department. He is nw wrking with H.W Mre Assciates f Bstn, Massachusetts, as a transprtatin prject planner L A.@ m 100% Rbert N. Grven is sectin head in charge f dwelpment activities in the Tmnspflatin and Public Wrks Department f the City f Frt Wrth. His respnsibilities include trafic impact studies, subdivisin review, radway and drainage design, and jld plain review Green has a B.C.E.S. (engineering science) and an M.S.C. E. (transprtatin) frm New Jersey nstitute f 72chnlgy. He is a registered prfessinal engineer in T~s and Ohi. Green is an Assciate Member f TE Mn Tue Wed Thur Fri Sat Sun Day f Week Figure 3. Daily attendance trend. Abbas Behntunesh is a ttunsp~atin engineer with the City f Frt Wrth. He received a B.S.C. E. and an M.S.C. E. frm the Universityf T= at Arlingtn. He has been with the City f Frt Wrthsince 198S.Behrnanesh is an assciate member f the T-s Sectin f L% He is a registeredprfessinal engineer in T-. TE JOURNAL s MARCH

4 weekends and public hlidays during the spring and summer mnths. The existing 710 parking spaces can nly accmmdate apprximately 5,050 visitrs a day. The z attendance recrds shwed there were 33 days during 1986 when the z had ver 5,050 visitrs, while an averagepeak day had abut 6,000 t 7,000 visitrs. Attendance reached its peak at 9,700 n the July 4 hliday. Attendance recrds als indicated that days when the number f visitrs reached abve 5,000 were weekends and hlidays during the spring and summer mnths. Prjectins shw that attendance may reach 19,000 by the year 2000 when the expansin is cmplete. T prvide parking fr 100% f the z visitrs all year rund, the parking lt will have t have abut 2,700 spaces. The prpsed parking lt f 1,100spaces will be 1,600 spaces shrt. 50 Parked Uehicles Out-ging LJehicles Cnclusin Based n ur analyses, the street netwrk has sufficient capacity t handle the added traffic. The intersectins analyzed will be perating at levels-f-service B and C. Parking, hwever, is significantly inadequate. After studying these analyses and examining the plitical aspects f the situatin, it was decided that it wuld nt be apprpriate fr us t recmmend the size f the parking lt. We believed such a decisin had t be made by the neighbrhd grups, city cuncil, and the Zlgical Assciatin. nstead, we develped a nmgraph t shw parking needs at varius levels f attendance and the number f days that these needs culd be served in the z sparking lts and the number f days the lts wuld be inadequate (see Figure 6). Because the z is a very unique land use, its trip generatin and parking charac= teristics maybe very different frm ther land uses. ~ Hur f The Day Figure 4. Hurly pattern f entering, exiting, and parked vehicles during an nnpeak day &,: 700 E : : 600 t ~ % 500 g prpsed Legal Limit Ma~imum Limit Legal Limit v H flttendance 1,345 At the time this article was written, the city cuncil had decided t allw fr the z t expand t apprximately 57 acres instead f the prpsed 100 acres. City staff was asked t develp a parking plan with the ~me f Day Figure 5. Parking accumulatin analysis. 38. TE JOURNAL MARCH 1989

5 Subscribe t TE Jurnal Yur nfrmatin Surce t s tugh keeping current with new advancesand techniques in transprtatin engineering. But TE Jurnal, the mnthly magazine written and edited fr transprtatin engineers, makes that jb easier. Each mnth, it brings yu articles and departments cvering the latest develpments, practices, techniques, and prducts in the field f transprtatin engineering. Fr nly $40 ($55 utside the U.S., Canada, and Mexic), yu can get yur wn subscriptin t TE Jurnal. All it takes is a phne call tday: call the TE Bkstre at (please have yur MasterCard r Visa number handy). Or send yur rder with payment (check r credit card infrmatin) t nstitute f Transprtatin Engineers 525 Schl St., S.W., Suite 410 Washingtn, D.C Cable,Wire supplies and equipment 24-hr shipments frm stck! *Traffic Signal and Cntrl Cable *ntercnnect and Cmmunicatin System Cable *Fire and Plice Alarm Cable *Fiber Optic Cable *Clsures & Supprt Hardware Call tday fr quick qutatins! cllect PAX: CLFFORD OF VERMONT, NC P O Bx 51, Bethel,Vermnt050S2 guideline f preserving the existing pen space and recreatinal facilities in the park. Putting additinal parking spaces inside the park was t be avided as much as pssible. Althugh the staff has nt yet develped a final parking plan, ne f the likely alternativesis tlease a parking lt frm an ftice building cmplex acrss frm the Trinity River frzvisitr use during the weekends and public hlidays. The lt has mre than 400 spaces and is abut nequarter f a mile frm the new entrance t the z. The remaining bstacle is t find sme acceptable frm f shuttle service between the parking lt and the z. Trip generatin and parking generatin data used in this study are specific t the Frt Wrth h. Such rates shuld nt be applied t ther zs. Hwever, a similar methd fr cllecting trip and parking generatin rates may be applied t ther land uses where rates are nt available. References 1. nstitute f Transprtatin Engineers. Trip Gene@ n,4th ed. Washingtn,D.C.: TE, nstitute f Transprtatin Engineers. Parking Generatin, 2d ed. Washingtn,D.C.: TE, % *_ 95% 90% 85% F *E *O k flttendance Leuel * c Parking Spaces Needed (yr..2ooo) Fl=t9,400 Ekample [pint B) 6=16,400 C=12,4W 2,300 parking spaces will result in 0=9,700 4 dayslgear parking de fiencg E=8,300 r 99.0% al the yew haue sufficient F=7.900 parking space Figure 6 Nmgraph fr dcmerminingparking needs. R TE JOURNAL. MARCH 4989s 39