VOL. 5, NO. 12, December 2015 ISSN ARPN Journal of Science and Technology All rights reserved.

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1 0-05. All rights reserve. Gp Acceptnce Stuy t T-Intersection with on-street Prking Minho Prk, Chunjoo Yoon*, 3 Young Rok Kim Senior Resercher, Kore Institute of Civil Engineering n Builing Technology, Kore Resercher, Kore Institute of Civil Engineering n Builing Technology, Kore (* Corresponing Author) Ph.D. Stuent, Deprtment of Trnsporttion Engineering, University of Seoul, Kore 3 Senior Resercher, Kore Institute of Civil Engineering n Builing Technology, Kore Professor, University of Science & Technology, Kore minhoprk@kict.re.kr, cjyoon@kict.re.kr, 3 kict.re.kr ABSTRACT The sight istnce t unsignlize intersections is one of the funmentl geometric esign elements n cn enhnce sfety n opertions. Fctors of ISD (Intersection Sight Distnce) moel in the AASHTO Policy on Geometric Design for Streets n Highwys, i.e. the Green book (00, 004) re ifferent from those prior to 00. The most ifferent thing is criticl gp tht hs been use from Green book 00. An lthough one type (All-Wy Stop Controlle intersection) of intersection hs been e to Green book 00, ISD on the ro with on-street prking is not consiere. Also, it is expecte tht sight istnce t intersection with on-street prking might be inclue in esign criteri becuse it hs one importnt restriction other thn stop controlle intersections tht prke crs coul be n obstruction preventing the sight istnce to rivers on the minor street. However, there is no consiertion of on-street prking in the intersection sight istnce criteri. Therefore, we hve compre the fctors which re chnge in the equtions, minly Green book (994 vs. 00 n 004), stuy the methos to fin criticl gp n pply those to T-intersection with on-street prking (site nlyze is one intersection in Stte College owntown, Pennsylvni, USA). Hopefully, this reserch coul be cornerstone of the future ro environment for utonomous vehicle which will be reche soon. Keywors: Criticl gp, intersection sight istnce, on-street prking. INTRODUCTION In generl, riving t n intersection requires greter ttention thn other situtions becuse there re numerous conflict points (e.g. 3 conflict points t intersection with 4 pproches), so creful plnning is neee to consier river s recting behvior, ccepting bility n sense to enhnce efficiency n sfety t the intersection. The river s bilities consist of perceptionrection time, jugment time, informtion processing time n ccelertion time of cr. Intersection sight istnce is one fctor mong ro plnning fctors tht reflect those chrcters well. The fctors n concepts t the intersections re ifferent between Green book (994) n 00. The most notble ifferences cn be ivie into two clsses; ing the AWSC (All-Wy Stop Control) to the previous five types of intersections n introuction of the criticl gp, which will be iscusse in the next section. However, there is no consiertion of on-street prking. Street-prke crs cn be clssifie s obstcle s they re locte closes the intersection n cn obstruct the view of the rivers on the minor ro who re looking for proper gp. So this pper contins the ifferent fctors in the Green book history bout criticl gp n the methos tht hve been use to nlyze fiel t n efines the vlue of the criticl gp. The efine reserch scope follows more etil. - Conucting literture reviews relte to the criticl gp, the theory, n iscussions of vrious spects of gp moeling. - Ientifying stuy site tht fits the escription of stnr intersection with on-street prking. - Collecting rejecte n ccepte gp t in the fiel. - Fining gp cceptnce vlues bse on number of moels from the literture reviews. - Reporting criticl gp vlues n the future stuy.. LITERATURE REVIEW. Intersection Control Cses in Green book The first thing ws fining the ifferent concepts of the ISD in the Green book. Prior to tht, the types of intersections re chnge from Green book (994) to 00 n this will be presente first, which is efine n ientifie in the Green book. AASHTO (994) AASHTO (00) Tble : Intersection types CseⅠ. Uncontrolle Intersection CseⅡ. Yiel Controlle Intersection Crossing mneuver from Minor Left or Right turn from Minor CseⅢ. Stop Controlle Intersection Crossing mneuver from Minor Left-turn from Minor Right-turn from Minor CseⅣ. Signl Controlle Intersection CseⅤ. Left Turn from Mjor Highwy CseⅥ. All-Wy Stop Controlle Intersection. History of Criticl Gp Severl stuies hve estimte gp-cceptnce t intersections with stop control on the minor ro. In the 940s, Green shiel reporte the verge minimum gp cceptnce ws 6.sec. Rff suggeste criticl lg n gp ws 5.9 n 6. sec, respectively. Bissell ccomplishe the stuy t two intersections n foun 5.8 sec s gp intervl. Solberg n Oppenlner suggeste 7.36, 7.8 n 7.8 sec s mein gp of right, left turn n through movements using probit nlysis. In the stuy of 65

2 0-05. All rights reserve. Rwn et l., they use the logit moel to etermine gp ccepte by 50 percent of rivers with vrious objects such s multilne, ivie highwys, n six intersections. Polus foun 7.47 sec t two intersections in Isrel. Kyte et l., conucte n nlysis for inclusion in the Highwy Cpcity Mnul (HCM Chpter on Unsignlize Intersection). He i the stuy with 30 Tble : Gp vlues from mjor gp-cceptnce stuies three-leg intersections n 4 four-leg intersections in five ifferent regions n use the mximum likelihoo metho, which Trout beck use. Drzents et l., collecte gp t t one loction in 0 ys in the Unite Kingom n reporte the mein ccepte gps is 6.58 sec in ylight n 5.6 sec in rk conitions. Stuy (Anlysis Metho) Object Mesure Gp Green shiel, 947 (Green shiel Metho) Rff, 950 (Rff Metho) Bissell, 960 (Bissell Metho) Solberg & Oppenlner,, 966 (Probit Anlysis) Rwn et l., 980 (Logit Moel) - Crossing - Crossing Avg. minimum cceptble time gp = 6. sec Criticl lg = 5.9 sec Criticl gp = 6. sec intersections Crossing Criticl gp = 5.8 sec 4 intersections Multilne Divie highwys 6 intersections Right Turn Left Turn Through Right Turn Through, one mneuver Through, two mneuvers Left Turn, one mneuver Left Turn, two mneuvers Trucks, ll mneuvers 7.36 sec 7.8 sec 7.8 sec Gp ccepte by 50% of rivers 6.73 sec 7.90 sec 7.0 sec 6.3 sec 6.60 sec 8.40 sec Polus, 983 (Rff Metho) Drzents, Holms, McDowell, 980 (Probit Anlysis) intersections in Isrel intersection in UK Right Turn from minor to mjor, Yiel Right Turn from minor to mjor, Stop Left Turn Criticl Gp Criticl lg 5.0 sec 5.0 sec 7.47 sec 7.55 sec 6.58 sec ylight 6.3 sec twilight 5.6 sec rkness 3. METHODS 3. Green Shiel Metho Green shiels et l. me moel using histogrms to fin the time gp. In this moel, the horizontl xis(x) represents gp length (sec) n the number of gps ccepte or rejecte per time gp is represente on the verticl xis(y) ccoring to the efinition, verge minimum cceptble time gp, s the minimum time gp tht is ccepte by more thn 50 percent of the rivers. 3. Rff Metho This metho ws propose by Rff n Hrt (950) to estimte the criticl gp. Rff et l. efine criticl gp (L) s the size gp for which the number of ccepte gps shorter thn L is the sme s the number of rejecte gps longer thn L. This efinition tkes the form of the intersection of gp-rnge grph versus the two cumultive curves on number-of-cceptnces. Two cumultive curves tht consist of cceptnces ginst gp rnge grph re use. The cceptnce curve is represente by cumultive ccepte gp with gp size less thn the given gp size n the rejection is the sme wy with gp size lrger thn the given gp size. Accoring to the lter stuies, becuse the cceptnce of lgs is not significntly ifferent from gp cceptnce, two lterntive pproches re use to solve it. The first pproch is using seprte lg n gp t n the other is combintion of the gp n lg t which ssume tht there is no sttisticl significnce between two t (lg n gp). The criticl gp is etermine t the point where the two curves re crosse. t c q () Where, t c : criticl gp(sec), µ : men vlue of ccepte gp istribution, q : volume of mjor ro(veh/sec), n σ : stnr evition of ccepte gp istribution 653

3 0-05. All rights reserve. 3.3 Logit Metho Fitzptrick (99) use the logit metho to estimte the criticl gp t unsignlize intersections. The logit is liner eqution tht is chnge from logistic, when epenent vribles cn be expresse by cceptnce or rejection gp. Logistic regression cn fin the probbility tht gp cceptnce (event) will hppen or not. Logistic function eqution cn be expresse by Eqution, which cn be chnge to the liner form s shown in Eqution 3. P exp{ ( 0 X )} () Where, P : probbility of ccepting gp, X : vrible relte to the gp cceptnce ecision, gp length, n Β 0, β : regression coefficients. P P' log e 0 X P Where P equls the trnsforme probbility. 3.4 Mximum Likelihoo Metho (Trout beck Metho) The mximum likelihoo metho ssumes tht the istribution of criticl gp follows log-norml istribution n fins the probbility tht the criticl gp woul be between the lrgest reject n ccepte gp(eq(4)). (3) 3.5 Ashworth Metho Ashworth (968) prove tht there ws bise gp istribution ue to trffic volume on mjor ro n fter removing it, he suggeste the consistent criticl gp metho of volumes on ll mjor ros. In orer to clculte it esily, he ssume trffic volume on the mjor ro follows negtive exponentil istribution n the minimum criticl gp of the cr on the minor ro follows norml istribution. In this cse, criticl gp istribution is bise to s q in cceptnce gp istribution. Ashworth suggeste the following Eqution0 to compute the criticl gp vlue. t c m s q Where, m : men of cceptnce gp, S : stnr istribution of cceptnce gp, n q : trffic volume on the mjor ro(veh/sec). 4. FIELD STUDY 4. Collecting Dt Metho The tritionl metho to exmine the gp is presente in Figure. The most importnt thing is tht vieo cmer shoul be locte in the plce where it cn cpture the length of the ro without ny brrier. (8) L n [ F ( ) F ( r )] r (4) Then, the log of this function is expresse s LL n ln[ F ( ) F ( r )] r Where, F n F r : the cumultive istribution for the norml istribution of gp ccepte n rejecte, respectively, : the gp ccepte by the river, n r : the gp rejecte by the river. Through the fining the mximum vlue of the mximum likelihoo function, the men ( ) n vrince ( ) re estimte. 0.5 E( t c ) e (6) Vr( t c ) E( tc ) ( e ) (7) (5) Figure : Typicl wy for collecting t Site selection ws conucte by pre-observtion in Downtown re of Stte college where one-wy ro with two trveling lnes n on-street prking is instlle. The intersections in re re presente in Figure. There re three types of intersections: Signlize (Burrowes, S.Frser, Allen, Pugh n Grner), Unsignlize without on-street prking (McAllister n Hetzer) n Unsignlize with on-street prking (Locust, Hiester n Sower). The Hiester intersection ws selecte s stuy re becuse loction of on-street prking on Sower n Locust intersections is more fr wy from intersection s curb thn Hiester intersection, lso the istnce between intersections is closer, which mens there is possibility tht trffic queue in jcent intersection cn ffect the criticl gp vlue. 654

4 0-05. All rights reserve. Figure : Intersections in stte college re 4. Dt Gp t were collecte uring 8hr n 45min in 3 ys; totl ccepte gps re 03 n rejecte gps re Tble 3: Percentge of vehicle n river type 498. More etil informtion is shown in Tble 3. Dt were collecte by 3 ctegories for the vehicle types(s : SUV, P : Pssenger cr, n T : Truck) n by rivers gener(m : Mle, n F : Femle) bse on the ssumption tht ech vehicle type n rivers gener hve ifferent gp vlue. However, totl number of t ws not enough to nlyze gp by types of vehicle n river so tht vlues for ech vehicle n river type coul not be conucte in this pper. Vehicle Type # of Dt Percentge Driver Type # of Dt Percentge SUV 0 9.4% Mle Driver % Pssenger Cr % Femle Driver 0.39% Truck % Totl % Totl % 5. COMPARISON OF FINDINGS 5. Green Shiel Metho When using the Green shiel metho, the verge minimum cceptble time gp occurs t 6.5 sec (seven rivers ccepte n three rivers rejecte the gps between 6.0 n 6.5 sec). Figure 4: Rff metho Figure 3: Greenshiel metho 5. Rff Metho The Rff metho involves etermintion of the cumultive istribution of the number (percentge) of rejecte gps n the complement of the cumultive istribution of the number (percentge) of ccepte gps. The criticl gp coul be consiere to occur t the point where the two istributions cross; in this stuy, the criticl gp occurs 6.5 secon, s shown in Figure Logit Metho The curve of Logit metho is shown in Figure 5. An the probbility of cceptnce gp is clculte by solving Eqution 3. The time gps for 50 n 85 percent probbility cn be erive by substituting 0.5 n 0.85 for P in Eqution 9: 0.5 P' log e 7.8. X % 0.85 X 50% 6.46sec P' log e 7.8. X 85% 0.85, X sec % Fifty percent of the rivers ccepte gp of 6.46, n 85 percent ccepte gp of 7.89 sec., 655

5 0-05. All rights reserve : : : : : Figure 5: Logit metho 5.4 Trout Beck Metho Tble 4 shows the result of Trout beck metho. Men vlue of the log Criticl gp is.90 n the stnr evition of the log Criticl gp is 0.. Accoring to eqution 6, secon is the criticl gp for Trout beck metho. Tble 4: Percentge of vehicle n river type i ccept reject log ccept log reject : : : : : Ashworth Metho In this pper, the cceptnce vlue for Ashworth metho ws not ble to erive. In orer to compute the vlue using Ashworth metho, trffic volume on the mjor ro shoul be known mentione in 3.5 Ashworth Metho. Also, the t ws collecte by mnully so tht collecting the trffic volume on the mjor ro ws impossible. 5.6 Comprison of Vlues We hve use 3-types of methos to fin the criticl gps on the intersection with on-street prking: Green shie Rff, n Logit metho. The result is shown below with the vlues in Green book n previous reserches for comprison. Tble 5: Comprison of the result Green book Left-turn Literture Left -turn This Stuy Left-turn Pssenger Solberg & 7.5sec 7.8 sec Green shiel 6.75 sec Cr Oppenlner Rff 6.50 sec Single-unit One 9.5sec 6.3 sec Truck mneuver sec Rwn Percent Logit Combintion et l sec Truck Two 7.89 sec 6.60 sec percent mneuver HCM 7. sec Trout beck 6.85 sec The criticl gp vlues for left-turn in Green book n previous litertures re between 6.3 n.50 secon. On the other hn, this stuy foun the criticl gp vlues between 6.5 to 7.89 secon. In ition, when compring with the criticl gp for right-turn uner the similr behvior of right turns on regulr intersection n left turns on one-wy ro of site nlyze, similr vlues from the previous stuies(6.5~7.47sec) re erive. Although irect comprison is impossible becuse this stuy i not ivie t into vehicle type, previous stuies were conucte t the intersection without on-street prking, n vlues in Literture were conucte in erlier er, this results re little ifferent from the first expecttion tht the criticl gp on the street with on-street prking is much longer thn the vlues on the street without on-street prking becuse prking cr coul be n obstcle to prevent river s sight istnce. However, when consiering the chrcteristic of the stuy site, these vlues coul be hppening. The spee limit on the mjor ro (5mph) is lower thn the site in literture. This mkes rivers on the mjor control cr quickly in response to the cr from minor ro. In ition, the intersections in Downtown consist of signlize n unsignlize intersections. An the istnce mong ech intersection is so close tht the trffic sitution t ech intersection cn ffect tht t ech intersection. Also, there is time gp in signlize 656

6 0-05. All rights reserve. intersection between phsing chnge. So every cr tht wnts left-turn cn mke left turn when phse chnge. 6. CONCLUSIONS AND FUTURE STUDY This stuy ws conucte to fin criticl gp for left-turning movement on the ro with on-street prking. Totl time for collecting t ws spent uring 8hr n 45min in 3 ys t Hiester Intersection (Unsignlize intersection of the Downtown in Stte College). 03 ccepte gps n 498 rejecte gps were collecte n use to nlyze the criticl gp in this stuy. Although t ws collecte bse on vehicle type (SUV, Pssenger Cr, n Truck) n river s gener (Mle n Femle), the number of t ws not enough to nlyze the criticl gp by ech type. The use methos for fining criticl gp were Greenshiels, Rff, n Logit metho. The vlue with Ashworth metho ws not ble to compute ue to the lck of trffic volumes on the mjor ro. The criticl gp ws clculte by ech metho (Green shiel: 6.5 sec, Rff : 6.50 sec, n Logit : 6.46 sec(50%), 7.89 sec(85%)). Although irect comprison to the vlues in the previous stuies is impossible, vlues re little shorter thn the expecte result n this is expline by the chrcter of the stuy site. When strting this stuy, longer criticl gp ws expecte becuse of the prking cr tht coul be n obstcle. However, the results re ifferent from the expecttion. When consiering the results, future stuies shoul be conucte in the re where there re no effects of jcent signlize intersection. An one thing tht this stuy i not nlyze is criticl gp on the ro without on-street prking in Stte College re. If this vlue is lso shorter, the result tht criticl gp vlues with on-street prking in Stte College Are re short coul be expline more obviously. Also, if more t on vehicle n river type coul be collecte in the future, more exct n rel criticl gp coul be foun. In ition, this kin of effort to fin gp woul be necessry to increse the ro sfety for utonomous vehicle s reucing the likelihoo of conflicts between vehicles. ACKNOWLEDGEMENTS This reserch ws supporte by grnt from n Inustril Innovtion Reserch Project (Stnr open DB estblishment n evlution system for intelligent vehicle wreness technology support, No.00594) fune by the Ministry of Tre, Inustry n Energy of Kore. REFERENCES [] A Policy on Geometric Design of Highwys n Streets, Americn Assocition of Stte Highwy n Trnsporttion Officils, Wshington, D.C. 994, 00, n 004. [] Hrwoo, D. W., J. M. Mson, R. E. Bryi, M. T. Pietruch, n G. L Gittings. NCHRP Report 383: Intersection Sight Distnce, TRB, Ntionl Reserch Council, Wshington, D.C., 996. [3] Ky Fitzptrick (99). Gps Accepte t Stop- Controlle Intersections. Trnsporttion Reserch Recor 303, pp.03~. [4] Hrwoo, D. W., J. M. Mson, R. E. Bryi (000). Sight Distnce for Stop-Controlle Intersections Bse on Gp Acceptnce. Trnsporttion Reserch Recor 70, pp.3~4. [5] J. L. Gttis, Ph.D., P.E., n Sonny T. Low, Gp Acceptnce t Nonstnr Stop-Controlle Intersection, MBTC FR 059. [6] Illinois Deprtment of Trnsporttion (006), Bureu of Locl Ros & Streets Mnul Eition, chpter 8. AUTHOR PROFILES Minho Prk hve complete PhD egree t the Pennsylvni Stte University in the U.S. Currently, he is working s senior resercher t the Kore Institute of Civil Engineering n Builing Technology. Chunjoo Yoon receive his mster s egree in geoinformtics engineering t the Inh University in Kore. Currently, he is resercher t the Kore Institute of Civil Engineering n Builing Technology s well s PhD stuent in trnsporttion engineering t the University of Seoul in Kore. Young Rok Kim hs complete PhD egree in the University of Seoul in Kore. Currently, he is working s senior resercher t the Kore Institute of Civil Engineering n Builing Technology s well s professor t the University of Science & Technology. 657