Priority Rating of Highway Routine Maintenance Activities

Transcription

1 54 TRANSPORTATION RESEARC.H RECORD 1246 Priority Rating of Highway Routin Maintnan Ativitis TIEN F. FwA, KuMAREs C. SINHA, AND JoHN D. N. R1vERSON This papr prsnts a produr for dtrmining priority ratings of highway routin maintnan ativitis by highway lass and distrss ondition. In ontrast to th ommon prati of assigning priority ratings basd on an aggrgatd pavmnt ondition indx, a shm that gnrats maintnan ativity spifi priority ratings was adoptd in this study. Sin thr xists a larg numbr of maintnan ativity-highway lass-distrss svrity ombinations to b ratd, a partitiond two-stag survy produr was adoptd to rdu th numbr of fators in ah rating phas to a siz managabl by ratrs. This rating produr was usd to obtain priority fators for routin maintnan ativitis in Indiana. Ths priority data hav bn inorporatd into an optimal routin maintnan programming modl proposd for us at th distrit and subdistrit lvls of th Indiana Dpartmnt of Highways. Using th appliation as an xampl, th papr dsribs th salint faturs of th produr and th stps involvd in omputing th final priority sors for individual maintnan ativitis. It also provids an analysis of th Indiana data to dmonstrat how othr usful information on routin maintnan prati ould b drivd from this form of study. Effiint programming and shduling of routin maintnan ativitis ar vital to th suss of pavmnt maintnan managmnt at both projt and ntwork lvls. Mor and mor agnis ar now using or looking into th possibility of using omputr mathmatial modls to prform th work of programming and shduling pavmnt maintnan ativitis (1-5). Whil mathmatial programming of routin maintnan ativitis using th omputr undoubtdly has grat potntial for improving ffiiny and rduing osts, th appliability and usfulnss of th rsults obtaind from suh an analysis dpnd on th auray and rasonablnss of input and onstraint fators (1, 5). Th priority ratings of various routin maintnan ativitis ar on of th most important input fators, with a grat impat on th final outom of a mathmatial programming analysis. Unfortunatly, th omplt priority information that is rquird for a maningful programming and shduling analysis is vry oftn not availabl. Baus of th lak of priority information on routin maintnan ativitis, a survy was rntly ondutd in Indiana to aquir th nssary data. This papr dsribs th rating produr adoptd and th stps involvd in arriving at th final priority ratings for diffrnt routin maintnan ativitis by highway lass and svrity lvl of road distrss ondition. Using th Indiana data, analyss wr prformd to T. F. Fwa, Dpartmnt of Civil Enginring, National Univrsity of Singapor, Knt Ridg, Singapor, 511. K. C. Sinha, Shool of Civil Enginring, Purdu Univrsity, Wst Lafaytt, Ind J. D. N. Rivrson, Infrastrutur Division, Thnial Dpartmnt, Th World Bank, 1818 H St., N.W., Washington, D.C illustrat how othr usful information on routin maintnan prati ould b drivd from this form of study. Finally, th nd for ah highway agny to stablish maintnan priority ratings appropriat for its own program is strssd. CONSIDERATIONS IN PRIORITY RATING ASSESSMENT A numbr of diffrnt priority assssmnt shms hav bn rportd in th litratur (1, 3, 6-8). Pratially all of ths shms rly on dfining rtain numri indis, suh as pavmnt ondition indx, maintnan nds indx, and dft rating valu, whih ar omputd using data obtaind from pavmnt ondition survys. Ths indis form th basis for priority assssmnt purposs. Th ky diffrn btwn ths shms and th shm proposd in this study is that, instad of using an aggrgat indx to rprsnt maintnan nds and to st prioritis, th prsnt study dvlopd maintnan-ativity-spifi priority ratings. In othr words, priority ratings ar assignd xpliitly to routin maintnan ativity typs. Advantags and Disadvantags of Prsnt Approah Th form of priority ratings gnratd by th shm dsribd in this study has bn inorporatd in a highway routin maintnan optimization programming modl (9). Th xprin shows that th advantags of this approah inlud th following: 1. Maintnan-ativity-spifi priority ratings hav a larut physial maning that is asily undrstood by both planning and fild maintnan prsonnl. In ontrast, using a numri indx to rprsnt diffrnt distrss onditions involvs data transformation and subjtiv judgmnt that may not b shard by th maintnan prsonnl at diffrnt lvls. 2. Spifi routin maintnan ativitis an b asily mathd with labor, matrial, quipmnt, onstrution produtivity, and tim rquirmnts. This link is partiularly usful in programming and shduling routin maintnan ativitis for agnis dirtly involvd with planning and xuting fild maintnan. Th stablishmnt of suh a link is not straightforward in shms whr aggrgat pavmnt onditions indis ar usd as th basis for priority rating. 3. Data olltd in th maintnan-ativity-spifi priority rating shm an b furthr prossd, as illustratd in a

2 Fwa t al. latr stion of this papr, to xtrat usful information on routin maintnan prati. Muh of this information would b lost if maintnan nds data ar aggrgatd into a ommon numri indx. Th disadvantag of th proposd approah is with th aquisition of priority rating data. Th numbr of ntris to b priority ratd is muh biggr and mor diffiult to handl, ompard with a singl indx variabl in most ondition-indxbasd priority-stting shms. on may hoos to produ diffrnt sts of priority lists for diffrnt sasons. In th prsnt study, Fators l, 2, and 3 wr onsidrd xpliitly. Fators 5 and 6 wr addrssd at th survy sampling stag, whn aras with diffrnt onditions in th two fators wr idntifid and sampld sparatly. Baus th survy was ondutd in th summr, th rsults may not b appliabl to wintr months du to sasonal ffts. Fator 7 was not inludd, but it is likly that misllanous fators inflund individual ratrs in arriving at thir priority sors. 55 Fators Affting Priority Ratings Th rlativ prioritis of various routin maintnan ativitis ar inflund by a numbr of fators. Th followinii; possibl fators wr idntifid in th prsnt study: 1. Routin maintnan ativity typ. Highway pavmnt routin maintnan nompasss ativitis undrtakn on a rgular or ontinual basis to srv as (a) prvntiv masurs against pavmnt dtrioration or as (b) orrtiv masurs to rpair minor pavmnt damags. Eah of ths ativitis has a diffrnt impat on rstoring pavmnt ondition and lngthning of pavmnt srvi lif. 2. Highway lass. Highways of diffrnt lassifiation riv diffrnt dgrs of attntion from highway agnis. A highway with a highr dgr of importan will riv maintnan arlir than anothr highway nding th sam typ of maintnan. 3. Road distrss ondition. A highway stion with a mor svr distrss would b rpaird soonr than on with a lss svr distrss ondition. 4. Sasonal fft. Not all maintnan ativitis an b prformd throughout th yar. For instan, rtain ativitis may hav to b suspndd in th wintr baus of ithr wathr onstraints or onsidrations of rpair fftivnss. Ths ativitis would thrfor b givn no priority during th wintr months, vn though thy might hav high prioritis in th othr sasons of th yar. 5. Climati and nvironmntal fators. Pavmnts in rgions with diffrnt limat and nvironmntal onditions bhav diffrntly. Th prvailing typs of pavmnt distrsss in diffrnt rgions ar not likly to b th sam. Th priority ratings for diffrnt maintnan ativitis would thrfor b diffrnt. 6. Maintnan prati and poliy. Highway agnis with diffrnt maintnan pratis and poliis pla diffrnt mphass on diffrnt aspts of maintnan. Thir priority ratings for various routin maintnan ativitis would not b th sam. 7. Misllanous fators. Priority ratings of maintnan ativitis may also b afftd by safty onsidration, nvironmntal onrn, politial influn, and othr fators. In thory, if nt> n 2, n 3, n 4, n 5, n 6, and n 7 rprsnt rsptivly th numbr of variabls in ah of th svn fators abov, on would hav to rat in priority ordr a total of (n 1 x n 2 X n 3 X n 4 X n 5 X n 6 X n 7 ) ombinations. This is, howvr, rarly th as in prati. For xampl, Fators 5 and 6 ar likly to b loation spifi and would not vary gratly ovr a rlativly larg ara. To aount for Fator 4, THE SURVEY PROCEDURES Th survy bgan with a statistial sampling of survyd units, followd by fild intrviws of maintnan prsonnl in th sltd units. Dtails of th two phass ar dsribd blow. Statistial Sampling Th survy units in this study wr sltd from a stratifid random sampling pross (1, 11). A stratifid random sampling is a rstritd randomization sampling dsign in whih th xprimntal units ar first sortd into homognous groups or bloks. Th rquird numbr of xprimntal units is thn randomly sltd within ah group. Thr ar thr lvls of maintnan managmnt in th Indiana Dpartmnt of Highways (IDOH): ntral offi lvl, distrit lvl, and subdistrit lvl. Figur 1 shows th distrit loations in Indiana. Th six distrits larly provid a logial LAPORTE DISTRICT VINCENNES DISTRICT FORT WAYNE DISTRICT SEYMOUR DISTRICT FIGURE 1 Highway distrits in Indiana as stratifiation basis for survy sampling.

3 56 basis for stratifiation. Two subdistrits wr randomly sltd from ah distrit to form th survy units. Th stratifiation by distrit also srvs wll to rprsnt two distint limati onditions found in Indiana. Past studis in Indiana (12,13,14) hav indiatd th prsn of two limati rgions: th oldr north rgion, rprsntd by th two northrnmost distrits; and th rlativly warmr south rgion, whih inluds th rmaining four distrits. A total of 36 rprsntativs of maintnan staff from th survy units wr survyd. Sixtn of th staff survyd wr from th north rgion and 2 from th south rgion. Priority Rating Produr Th fators inludd in th survy wr maintnan ativity typ, highway lass, and distrss svrity lvl of th road nding th ativity. Fourtn routin maintnan ativitis involving pavmnt, shouldr, and drainag wr invstigatd. Tabl 1 prsnts th list of maintnan ativitis invstigatd. Th highway lasss dfind wr (a) Intrstat and (b) othr stat highways (OSH). OSH was furthr brokn into two atgoris: high-traffi-volum OSH, with mor than 4 vhils pr day (vpd); and low-traffi-volum OSH, with lss than 4 vpd. Th traffi volum lassifiation was hosn to provid broad guidlins for diffrntiating maintnan prioritis of th various highways. For road onditions, thr TABLE 1 LIST OF HIGHWAY MAINTENANCE ACTIVITIES INVESTIGATED Cod 21 Shallow Pat.hing 22 Dp Pathing 23 Prmix Lvling Dsription 24 Full Width Shouldr Sal 25 Sal Coating ~ Chip Sal 26 Saling Longitudinal Craks and Joints?.7 Crak Saling 28 Sand Sal 21 Spot Rpair of Unpavd Shouldrs 211 Blading Unpavd Shouldrs 212 Clipping Unpavd Shouldrs 213 Ronditioning Unpavd Shouldrs 231 Clan and Rshap Diths 234 Motor Patrol Dithing TRANSPORTATION RESEARCH RECORD 1246 lvls of distrss svrity wr onsidrd-svr, modrat, and slight. A simpl alulation shows that thr ar 14 x 3 x 3 = 126 ntris to b priority ratd. Simultanous rating of all 126 ntris was out of th qustion. Pairwis omparison was thortially possibl but not pratial du to th larg numbr of possibl ombinations. To rdu th problm to a managabl siz, th ontributing fators wr partitiond into two atgoris and xamind indpndntly. Figur 2 shows th flow diagram of th survy. Part 1 of th survy dalt with assigning priority sors to individual routin maintnan ativitis in aordan with thir rlativ importan in prsrving highway pavmnt onditions at a dsird lvl. In Part 2, priority sors wr assignd to diffrnt pavmnts of various highway lasss by road distrss svrity lvl aording to th rlativ urgny of th nd for maintnan work. To aid ratrs in arriving at priority sors mor quikly and ffiintly, th following masurs wr takn: 1. A two-stag rating produr was adoptd. Ratrs wr first askd to rank th ntris with all potntial tis onsidrd. Kping th ordr of th ranks, th ratrs wr nxt askd to assign a priority sor to ah on a 1-point sal. 2. Instad of using tabls or forms, a st of ards with a diffrnt maintnan ativity writtn on ah was givn to ah ratr. By allowing ah ratr to pla th ards in rank ordr and thn mov thm into rlativ positions abov or blow ah othr along th 1-point sal, ralisti priority sors ould b assignd fairly quikly. Th xprin of th survy indiatd that this rating produr was wll rivd by ratrs, and satisfatory rsults wr obtaind in an unambiguous mannr. Figur 3 shows th priority rating sal along with ratr instrutions usd for Part 1 of th survy. An idntial sal and similar ratr instrutions wr usd for Part 2 of th survy. An altrnativ produr would hav bn to adopt a trlik survy strutur, as shown in Figur 4. Th ratrs would first rat all maintnan ativitis as in Part 1 of th survy in Figur 2, thn prod to rpat N 1 numbr of tims th Part 2 rating pross in Figur 2. Howvr, this produr is highly tim onsuming. Consquntly, th survy produr in Figur 2 was usd in this study. Th omputational and analyti thniqus disussd in th subsqunt stions of this papr ar, howvr, appliabl to both produrs. ANALYSIS OF SURVEY DATA This stion prsnts th rsults and omputs th final priority ratings of routin maintnan ativitis by highway lass and road ondition svrity lvl. In addition, this stion shows that th data gathrd in this form of study an b analyzd furthr to provid othr usful information on routin maintnan prati. As an illustration, an analysis is prsntd whih ompars th maintnan prati of th north and south rgions of Indiana.

4 Fwa t al. 57 (Part 1) (Part 2) Idntify Idntify Dfin routin maintnan highway lasss road distrss ativitis (Total N 1 numbrs) (Total N 2 numbrs) svrity lvls (Tota] N 3 numbrs) Stag I -- Rank N 1 ativitis in rlativ importan in prsrving highway pavmnts at a dsird lvl of srvi Stag I -- Rank (N 2 x N 3 ) onditions by thir rlativ urgny of nd for routin maintnan work Stag II - Assign priority sor Stag II -- Assign priority sor to ah of th N 1 ativitis to ah of th (N 2 x N 3 ) onditions I Comput priority rating of routin maintnan ativitis by highway lass and road distrss svrity lvl FIGURE 2 Ativity flow hart for th partitiond two-stag survy produr. Computation of Final Priority Ratings Th data olltd from Parts 1and2 of th survy (s Figur 2) ar pr ntd in Tabls 2 and 3. Lt/ 1 andf:z. rpr nt th priority sors obtaind from th tw parts. Th fina l priority ratings of au routin maintnan ativitis an b mputd as follows: F;jk = U1); x U2)jk i = 1, 2,, N 1, whr j = 1, 2,, N 2, k = 1, 2,, N 3 (1) F;jk priority rating for routin maintnan ativity i on highway lass j with distrs s vrity lvl k, 1 s Fijk::::; 1 (! 1 ); priority sor for routin maintnan ativity typ i in rlation to all othr routin maintnan ativity typs, 1 s (/ 1 ); s 1, (f 2 )jk = priority sor for ombination of highway lass j and distrss svrity lvl kin rlation to all othr ombinations of th two fators, 1 s (f 2 )ik ::::; 1, N 1 N 2 N 3 total numbr ofroutin maintnan ativity typs, total numbr of highway lasss, and total numbr of distrss svrity lvls. In Equation 1, th rating sor (f 2 )ik an b onsidrd to b a wighting fator applid to ah maintnan ativity. Th priority ratings thus omputd ar rordd in Tabl 4. Priority sors for both th north and south rgions ar prsntd in th sam tabl. Ths priority ratings provid th nssary information on th rlativ importan of various maintnan ativitis by highway lass and distrss svrity lvl. It should b mntiond that, instad of taking th produt of / 1 and f 2, a slightly diffrnt st of priority ratings, F;ik may b omputd by addingf 1 and/ 2 in th following mannr: i = 1,2,,N 1, j = 1,2,...,N 2, k = 1,2,,N 3 (2) whr W 1 and W 2 ar numri wighting fators and all othr symbols ar as dfind in Equation 1. Th fator 1 is inludd

5 58 TRANSPORTATION RESEARCH RECORD 1246 Priority Sor S1l Stp 1. Stp 2. Stp 3. Stp 4. Stp 5. Stp 6. You ar givn 14 routin mainlnan ativity typs, a.h writtn on a small ard. Go t.hrough and rad th ativity typs arfully. (Ra.nking Assignmnt) Hank tb ards on your ds k in aordan wit.h th importan of ah a~tivi y lyp in prsrving pavmnt. ondition at a dsird lvl. Put th most important ativi t.y at th top, followd by othr ativitis in th ordr of drasing importan. Tis ar allowd. Car fu lly rviw th ranking in Stp 2. Mak hangs if n ssary. Mov th top priority ard to th top (i.. a sor of 1) of th sal on this instrution sht. Nxt, mov on ard at a tim, in sn1un of dra ing importan, to th sor and a.ssign a sor to ah by om.paring with th ativity immdiatly abov it. Continu until all th ards ar plad on thp. sal. If th last ard dos not hav a sor of 1, adjust th sors (.~ pt th top sor) so that th lowst priority ativity has a sor of 1. Carfully rviw th priority sors assignd. Mak hangs if nssary. 3 2 FIGURE 3 Priority rating sal and ratr instrutions. so that F; 1 k will hav th sam rang as F, 1 k (i.., 1 ~ F{ k 1 ~ 1). In omparing th multipliation modl of Equation 1 and th addition modl of Equation 2, th absolut valus of individual priority ratings do not arry muh physial maning. It is thir rlativ magnituds in th ntir st of priority rating sors that maks th diffrn in routin maintnan programming and shduling analysis. It is thrfor of intrst to xamin th ability of th two modls to diffrntiat rlativ prioritis of routin maintnan ativitis. Considr two maintnan ativity-highway lass-distrss svrity ombinations, A and B. Ltfai andfa 2 b th priority sors of A from Parts 1 and 2 of th survy, rsptivly, fb 1 and fb2 th orrsponding priority sors of B, and FA, F8, F~, and F~ b th rsptiv final priority ratings for A and B omputd from th two modls. Th following rlationships an b shown (15): Cas 1. min(fal> fa2) 2 max(fbt> fb2), fa1 -=/:- faz or fb1 -=!:- fbz or both. W h<tv FA > F 8 <tnd F',.. > F~. Th two modls agr. Cast: ax(f"1'!az) ::s min(fb1, fbz),!a1 -=!:- fa2 or fb1 -=!:- fb2 or both. W hav FA < F 8 and F',.. < F~. Th two modls agr. Cas 3. fat = faz = fb 1 = fbz W hav FA = F8 and F',.. = F~. Th two modls agr. Cas 4. max(fa1,fa 2 ) 2 max(fb1,fb 2 ) 2 min(fa1,fa 2 ) 2 min(fb 1, fb 2 ). W hav FA 2 F 8 and F',.. 2 F~ Th two modls agr. Cas 5. max(fb1,fb2) 2 max(faijaz) 2 min(fb1,fb 2 ) 2 min(f" 1, [.2). W hav FA ~ F 8 <1nrl F',.. ~ F'y Th two modls agr.

6 .-- M'"r'-=a"Oin'-'t""'n"'a'i-'n""'" -----<1 Condut Part '.l Survy of, LIVlty l Figur 2 for Ativity 1, M~~a~i n~t~ n_n~n Condut Part 2 Survy of "! LIVlty '.. Figur 2 for Ativity 2 Coudut Part 1 Survy of Figur 2 for N 1 numbrs of maintnan ativitis Comput priority ratings of routin i maintnan ativitis by highway lass and road distrss svrity lvl._---'m;,..:;..;., a'"'in'- t.;..;n;;.;a:;;;n;.,;;..;.. Condut Part 2 Survy of, L1v1 y N, Figur 2 for Ativity N 2 FIGURE 4 Ativity flow hart for altrnativ survy produr. TABLE 2 RESULTS FROM PART 1 OF PRIORITY RATING SURVEY Haintnan North Rgion South Rgion Ativity Avrag Priority Sor Avrag Priority Sor Cod Rank Avrag 95% Conf. Intrval Rank Avrag 95% Conf. Intrval , , , ,9-8.4

7 TABLE 3 RESULTS FROM PART 2 OF PRIORITY RATING SURVEY Highway Distrss Svrity Avrag North Rgion Priority Sor Avrag South Rgion Priority Sor Class Lvl Rank Avrag 95% Conf. Intrval Rank Avrag 95~ Conf. Intrval Svr Intrstat Modrat Slight High Svr ,9-9, Volum 'Modrat ' OSH Slight Low Svr Volum 'Modrat OSH Slight TABLE 4 PRIORITY RATINGS OF ROUTINE MAINTENANCE ACTIVITIES BY HIGHWAY CLASS AND DISTRESS SEVERITY LEVEL lntntt Higll Volu.,_ OSH Low Volum OSH Rout in Maintnan D11tr11 Svrity Lv. Di1tr11 Svrity Lv. Distrn Svrity Lv. Ativity Cod Svr Modrat Slight Svr Modrat Slight Svr Modrat Slight ~ot: 99 (N) 86 (N) 62 (N) 93 (N) 71 (N) 43 (N) 73 (N) 49 (N) 1 (N) 94 (S) 76 (S) 39 ( S) 9 (S) 7 (S) 35 (S) 71 (S) 36 (S) 9 (S) 96 (N) 84 (N) 6 (N) 9 (N) 75 (N) 41 (N) 71 (N) 47 (N) 1 (N) 96 (S) 78 ( S) 4 (S) 92 (S) 7 (S) 36 (S) 73 (S) 35 (S) 1 (S) 72 (N) 63 (N) 45 (N) 68 (N) 56 (N) 31 (N) 53 (N) 35 (N) 7 (N) 54 (S) 44 (S) 22 (S) 52 (S) 39 (S) 2 (S) 38 (S) 21 (S) s (S) 49 (N) 43 (N) 31 (N) 46 (N) 38 (N) 21 (N) 36 (N) 24 (N) 5 (N) 35 ( S) 28 (S) 14 (S) 34 (S) 26 (S) 13 (S) 27 (S) 13 ( S) 4 (S) 64 (N) 56 (N) 4 (N) 6 (N) SO (N) 28 (N) 47 (N) 31 (N) 6 (N) 44 (S) 36 ( S) l~ (S) 42 (S) 32 (S) 16 (S) 33 (S) 16 (S) I 4 (S) 67 (N) 58 (N) 42 (N) 63 (N) 52 (N) 29 (N) 5 (N) 33 (N) 7 (N) 57 (S) 46 (S) 23 ( S) 55 (S) 42 (S) 21 (S) 43 (S) 22 (S) 6 (S) 68 (N) 59 (N) 43 (N) 64 (N) 53 (N) 29 (N) 5 (N) 33 (N) 7 (S) 65 (S) 53 ( S) 27 (S) 62 (S) 47 (S) 24 (S) 5 (S) 25 (S) 7 ( s) 56 (N) 49 (N) 35 (N) 53 (N) 44 (N) 24 (N) 41 (N) 27 (N) 6 (N) 29 (S) 23 (S) 12 ( S) 28 (S) 21 (S) 11 (S) 22 (S) 11 (S) 3 (S) 78 (N) 68 (N) 49 (N) 73 (N) 61 (N) 34 (N) 58 (N) 38 (N) 8 (!;) 71 (S) 58 (S) 29 (S) 68 (S) 52 (S) 26 (S) 54 (S) 27 (S) 7 (S) 7 (N) 61 (N) 44 (N) 67 (N) 55 (N) 3. (N) 52 (N) 34 (N) 7 (N) 59 (S) 48 (S) 24 (S) 57 (S) 43 (S) 22 (S) 46 (S) 12 ( S) 6 (S) 46 (N) 4 (N) 29 (N) 43 (N) 36 (N) 2 (N) 34 (N) 23 (N) S (N) 58 (S) 46 (S) 23 (S) 55 (S) 42 (S) 21 (S) 43 (S) 22 (Sl 6 (S) 42 (N) 37 (N) 26 (N) 39 (N) 33 (N) 18 (N) 31 (N) 21 (N) I 4 (N) I 65 (S) 53 (S) 27 (S) 62 (S) 47 (S) 24 (S) 5n s> 25 (S), 7 (S) 37 (N) 32 (N) 23 (N) 35 (N) 29 (N) 16 (N) 27 (N) IA (N) 4 (N) 78 (S) 63 (S) 32 (S) 75 (S) 57 (S) 29 (S) 59 (S) 3 (S) 8 (S) 19 (N) 17 (N) 12 (N) 18 (N) 15 (N) 8 (N) 14 (N) 9 (N) 2 "'I 66 (S) 53 (S) 27 (S) 63 (S) 48 (S) 24 (S) 5 (S) 32 (S) 7 < s l I (N) stands for North Rgion, and (S) stands for South Rgion.

8 Fwa t al. Cas 6. max(fa1ja2) 2: max(fb1,fb2) 2: min(faija 2 ) 2: min(fb 1, fbz), or max(fb1jb2) 2: max(fb1jb2) 2: min(fa1ja2) 2: min(fb1' fb2). Th two modls may agr or diffr, dpnding on th magnituds of fa1, f 2, fb 1, and fb2, and th rlativ valus of W 1 and W 2 in Equation 2. Th two modls produ th sam ordr of rlativ magnitud in priority ratings for Cass 1 through 5, but disrpanis ar found in Cas 6. This mans that (a) rgardlss of th omputation mthod usd, th top and bottom portions of th priority rating list ar likly to stay unhangd; and (b) th disrpanis would lad to som diffrns in th ordr of priority ratings in th middl portion of th list. In th ontxt of th prsnt study, th omputation sltd is unlikly to afft muh th rlativ priority ratings of important maintnan ativitis on Intrstat or high-volum OSH with high distrss svrity lvls. Ths ar th ativitis that ar of major onrn in a routin maintnan programming analysis. To quantitativly assss th diffrn btwn th modls, a statistial orrlation analysis was prformd (1) to ompar th st of priority ratings in Tabl 4 and on omputd from Equation 2 with W 1 = W 2. Th offiint of orrlation found was.966, showing an xllnt positiv assoiation btwn th priority ratings obtaind from th two mthods. Th impat of th hoi of omputation mthod is, thrfor, not likly to b grat on priority ratings usd for routin maintnan planning purposs. Whil th multipliation modl is usd in this study, on should not ovrlook th potntial usfulnss of th addition modl. A highway agny may to som xtnt influn th rsults in favor of rtain poliy prfrns through th us of wighting fators W 1 and W 2 Th valus of W 1 and W 2 ar, howvr, not xptd to b vry diffrnt from th simpl as of W 1 = W 2 in normal onditions. Analysis of Priority Rating Data An analysis was ondutd to ompar th maintnan prati of th north and south rgions of Indiana. Plottd in Figurs 5, 6, and 7 ar data obtaind from Tabl 4 for routin maintnan ativitis on Intrstat, high-traffi-volum OSH, and low-traffi-volum OSH, rsptivly. Baus of th larg numbr of data points in th tabl, thr plots instad of on wr prpard for larity of prsntation. In a priority rating omparison analysis, as mntiond in th prding stion, on is intrstd in th rlativ magnituds of priority valus within ah st of ratings. For instan, 61 ~ 1 a: LEGEND FOR s::. CONDITION SEVERITY: - 9 z SEVERE >. Q MODERATE > 8 SLIGHT -u < 7 Q) u I'll 6 Q) - I'll ::!: 5 Q). -:l 4 a: - 3 Cl -I'll 2 a: >. 1 a ~ 5 Lin of Equallty ~ Priority Rating of Routin Maintnan Ativity <South Rgion) FIGURE 5 Comparison of north and south rgion priority ratings for maintnan ativitis on Intrstat.

9 62 TRANSPORTATION RESEARCH RECORD 1246 O> 1 CD a:. - 9 z >- 8 > - < 7 CD I'll 6 CD - I'll 5 :E Q) -:::J a: - O> -I'll a: LEGEND FOR CONDITION SEVERITY: SEVERE Q MODERATE SLIGHT Q 8 Q Q Q Lin of Equallty ll Priority Rating of Routin Maintnan Ativity (South Rgion) FIGURE 6 Comparison of north and south rgion priority ratings for maintnan ativitis on high-volum OSH. Rating Panl A may award priority valus of 2, 3, 4, and 5 to four diffrnt maintnan ativitis, whil Rating Panl B awards 4, 5, 6, and 7, and Panl C awards 3, 2, 5, and 4 to th sam ativitis. It is lar that thr is no diffrn btwn th Panl A and B sors for th purpos of routin maintnan programming, but that th Panl C sors ar quit diffrnt from thos of th othr two. Th statistial offiint of orrlation, r, would again b an appropriat paramtr to masur this diffrn (1). Panls A and B would giv a r valu of 1., whih mans a prft linar assoiation btwn th two sts of priority sors. Panls A and C or B and C produ a muh lowr r valu of.6, indiating a rlativly poor assoiation btwn th two sts ompard. Using all th 126 pairs of priority sors in Tabl 4, omputation givs a valu of r qual to.74. This shows that th agrmnt btwn th priority ratings of th north and south rgions was only fair. Howvr, a losr xamination of th plots in Figurs 5, 6, and 7 shows that (a) all th points that li blow th lin of quality blong to four maintnan ativitis (212, 213, 231, and 234) and (b) all othr data points tnd to lustr rlativly losly within a straight band. A rvisd omputation onfirms th abov obsrvation. Th rsults ar indiatd in Tabl 5. Considring only th first 1 maintnan ativitis in Tabl 4, a r valu of.95 was obtaind. For th last four maintnan ativitis (i.., Ativitis 212, 213, 231, and 234) th r valu omputd was.69. Ths rsults rval that th north and south maintnan prsonnl wr in xllnt agrmnt ovr th priority ratings of most maintnan ativitis, xpt for th four ativitis mntiond abov. Ths four ativitis ar mainly drainag-rlatd maintnan work. Th south rgion prsonnl plad mor priority on ths ativitis ompard with thir ountrpart in th north rgion. This is possibly du to limati and topographial diffrns btwn th two rgions. Th south has stpr and mor rolling to hilly trrain. It also has mor rainfall, with an annual avrag of mor than 4 in. ompard with about 35 in. in th north. A study of th priority rankings in Tabl 2 indiats that both th north and south rgion maintnan prsonnl gav highst prioritis to pavmnt-rlatd ativitis suh as shallow and dp pathing, prmix lvling, and rak saling. Th main disrpany aros whn th south rgion maintnan prsonnl assignd appriably highr prioritis to th last four drainag-rlatd ativitis. If ths four ativitis ar st asid, th two groups of maintnan prsonnl agrd losly on th rlativ priority rankings of th rmaining ativitis. Ths obsrvations onur with ommnts mad in th prding paragraph. Th pattrn of th omparison plot sn in Figur.) for Intrstat is rpatd vry losly in th plot in Figur 6 for high-volum OSH and again in Figur 7 for low-volum OSH.

10 Fwa t al. 63 ~ 1 a:.s:; - 9 z LEGEND FOR CONDITION SEVERITY: >. 8 > - SEVERE MODERATE () SLIGHT ( 7 Cl> () I'll 6 Cl> - I'll 5 :!: Cl> 4 -::::J a: 3 Cl 9-2 -I'll a: >. 1 a.. Lin of Equallty Priority Rating of Routin Maintnan Ativity (South Rgion) FIGURE 7 Comparison of north and south rgion priority ratings for maintnan ativitis on low-volum OSH. This rflts indirtly a masur of onsistny in th rating rsults. Th partitioning thniqu and th two-stag produr usd in th survy pross appard to hav produd logial, ralisti ratings from th ratrs. Th thr plots also show a progrssiv shift in th position of gnral data points toward th low-priority ara (at th lowr lft-hand ornr of th plots) as on movs from Intrstat to high-volum OSH and thn to low-volum OSH. This roughly rflts th priority rankings of various highway lasss dpitd in Tabl 3. Summary of Findings Th main findings of th Indiana study ar summarizd blow: 1. Th partitiond two-stag survy produr was wll rivd by ratrs. Th pross was found to b quik, asily undrstood, and asily implmntd by maintnan prsonnl with diffrnt lvls of knowldg and xprin. Analyss of th data showd that logial ralisti ratings wr obtaind from ratrs. Th rsults providd a onsnsus viw of th unwrittn but important daily dision-making pross govrning routin maintnan pratis of th highway maintnan agnis in Indiana. 2. Th priority ratings from th north and south rgions of Indiana showd, ovrall, a fair dgr of agrmnt, although th south rgion maintnan prsonnl plad signifiantly highr prioritis on drainag-rlatd ativitis ompard with thir north rgion ountrparts. Th two groups showd xllnt agrmnt on th rlativ prioritis of othr routin maintnan ativitis. Both assignd highst prioritis to pavmnt-rlatd ativitis on Intrstat and high-volum OSH, and lowst prioritis to ativitis on low-volum OSH with modrat and low distrss svrity lvls. 3. Th diffrn in th priority ratings btwn th two rgions is blivd to b rlatd to th diffrns in thir limati and topographial onditions. On would thrfor xpt variations in priority ratings of maintnan ativitis arriong rgions with diffrnt limati and nvironmntal onditions. CONCLUSION A partitiond two-stag survy shm was implmntd and found to b fftiv in assssing priority ratings of routin maintnan ativitis by highway lass and road distrss svrity. Th maintnan-ativity-spifi priority data wr

11 64 TRANSPORTATION RESEARCH RECORD 1246 TABLE 5 COEFFICIENTS OF CORRELATION BETWEEN PRIORITY SCORES OF ROUTINE MAINTENANCE ACTIVITIES OBTAINED FOR THE NORTH AND SOUTH REGIONS OF INDIANA Croup of Maintnan <1SH with High OSfl with Low I All Highways I I Ativitis \ Intrstat Traffi Volum Traffi Volum Combind First 1 Ativitis in Tabl 4 Ativitis 212, 213, and 234 All 14 Ativitis ' in Tabl 4 informativ and usful in providing maningful insight into th routin maintnan pratis of highway agnis. Sin th priority ratings ar inflund by sasonal fators, limati and nvironmntal onditions, highway maintnan poliy mphasis, and pavmnt maintnan and rpair thnology, thr is a nd for ah highway agny to dvlop its own st of routin maintnan priority ratings and to priodially updat ths ratings as a part of th ontinuing pross of highway pavmnt maintnan managmnt. REFERENCES 1. A. Stin, T. Sullion, D. R. Smith, and S. Cox. A Miroomputr-Basd Pavmnt Rhabilitation and Maintnan Managmnt Systm. Pro., Sond North Amrian Confrn on Managing Pavmnts, Toronto, Canada, Vol. 2, 1987, pp C. A. Burk. Trnds and Countrtrnds in Maintnan Managmnt Systms. Transportation Rsarh Rord 951, TRB, National Rsarh Counil, Washington, D.C., 1984, pp P. E. Thbrg. Dvlopmnt of Mathmatial Modls to Assss Highway Maintnan Nds and Establish Rhabilitation Thrshold Lvls. Transportation Rsarh Rord 119, TRB, National Rsarh Counil, Washington, D.C., 1987, pp J. V. Carnahav, W. J. Davis, M. Y. Shahin, P. L. Kan, and M. Z. Wu. Optimal Maintnan Disions for Pavmnt Managmnt. ASCE Journal of Transportation Enginring, Vol. 113, No. 5, Spt. 1987, pp L. C. Bll. Maintnan Managmnt Systm Evaluation. Transportation Rsarh Rord 951, TRB, National Rsarh Counil, Washington, D.C., 1984, pp W. P. Kilarski and C. J. Churilla. Pavmnt Managmnt for Larg Highway Ntworks. ASCE Journal of Transportation Enginring, Vol. 19, No. 1, Jan. 1983, pp G. Shonbrgr. A Pavmnt Managmnt Information Systm for Evaluating Pavmnts and Stting Prioritis for Maintnan. Transportation Rsarh Rord 951, TRB, National Rsarh Counil, Washington, D.C., 1984, pp M. S. Snaith and J. C. Burrow. Priority Assssmnt. Transportation Rsarh Rord 951, TRB, National Rsarh Counil, Washington, D.C., 1984, pp T. F. Fwa, K. C. Sinha, and J. N. D. Rivrson. Highway Routin Maintnan Programming at Ntwork Lvl. Aptd for publiation in ASCE Journal of Transportation Enginring, J. Ntr, W. Wassrman, and M. H. Kutnr. Applid Linar Statistial Modls, 2nd d. Rihard D. Irwin, In., Homwood, Ill., F. M. Montngro and K. C. Sinha. Dvlopmnt of a Produr to Assss Highway Routin Maintnan Nds. Rport FHWA/ IN/JHRP-86/4. Joint Highway Rsarh Projt, Purdu Univrsity, E. J. Yodr and B. Colui-Rios. Truk Siz and Wight Issus. Pro., 66th Purdu Road Shool, Purdu Univrsity, Marh E. A. Sharaf. Analysis of Highway Routin Maintnan Costs. Ph.D. Thsis. Shool of Civil Enginring, Purdu Univrsity, T. F. Fwa and K. C. Sinha. A Study of th Effts of Routin Pavmnt Maintnan. Transportation Rsarh Rord 112, TRB, National Rsarh Counil, Washington, D.C., T. F. Fwa, J. D. N. Rivrson, and K. C. Sinha. Priority Assssmnt of Routin Maintnan Nds and Optimal Programming. Rport FHWA/IN/JHRP-88/6. Joint Highway Rsarh Projt, Purdu Univrsity, Publiation of this papr sponsord by Committ on Maintnan and Oprations Managmnt.