Highway Design and Traffic Safety
Highway Design and Traffic Safety CE 576
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This 24 page Class Notes was uploaded by Savanna Cruickshank on Friday October 23, 2015. The Class Notes belongs to CE 576 at University of Idaho taught by Ahmed Abdel-Rahim in Fall. Since its upload, it has received 36 views. For similar materials see /class/227777/ce-576-university-of-idaho in Civil Engineering at University of Idaho.
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Date Created: 10/23/15
Ahmed AbdelRahim PhD PE Horizontal Alignment 0 Kinetics of vehicles moving on a circular path 72in w roadway upnraiwznon 9mm ma mm mm Vacnr Wm WM m gummmnai barman u A m Wm WM mm mm mm mun x whichnumbilmmnumxuimlcmllvun mm nnxnmiyruimuwilcluml mm mm horizontal curves sight distance 390 nsiderations mm SSD at Horizontal Curves k orizontal Curves Distribution ofquote a 1d quotf5quot Over a range of Curves C For a given design speed five methods for sustaining an by using e and S lt7 Method e and H directly proportionate linear to IIR 6 Method 2 First then e lt7 Method 3 First e then Method 4 Same as 3 using running speed instead of design speeds lt7 Method 5 e and H in curvelinear relationship with IIR l orizontal Curves Distribution ofquotequot a 1d Over a range of Curves mmnmn m Swerdzvnuan Sn erckwahon mkx c c a Horizontal Curves Distribution of fxquot and Over a range ofCurves Design Speed 5 Hanan em 7 Dnrmxpunding y e dcaigr vuc H C orizontzl Curves Distribution of fsquot and ver a range of Curves Running Speed Zo c yonding r y mnmng gem H o orizontal Curve Design Consideration Maximum Superelevation Weather snow and ice 9 Terrain Area type 9 Speed change slow vehiclescongestion Design Consistency 0 maximum I2 in gravel roads 8 maximum for areas with snow and ice AASHTO considers maximum e from 4 to 2 Horizontal Curve Design Consideration 0 Minimum Radius Based on maximum Value for super elevation and side friction coef cient I Mama I us cusmmarv l 7 km r um unmmum 7m bifurlum A 1 Design Inr Rural Highways Urban Fveeways and Hignspeed Urban 5mm and Traf c Safety H rizontal Curve Maximum Values for f m an 21w mm Exlnmi Ha sun Fn mll Yumn fur Rum mm gunm Illglln pn39d l nmu Siml mum um l39mnAuu m nndulmmn m h mm mm I o 39izontal Curve Transi ion Curve De ign TangenttoCurveTransition n i pmim on mnoff with mom to PC a Location of the Supemlevz on runoff with mom to PT I Spiral CurveTransition r Length of the Spiml minimulm maximum2nd desirable aximum Radiu ength of xupemlevztion runoff Compound Curve Transition Hol ilontal Curve Tru 39k Offtracking Tra39 eledWay on Hot ilontal Curves min un nnmnnonmny on o non v uivxi rm n um no quotomquot 0 CE576 Highway Design and Traf c Safety Spring 2008 Lecture 14 Ahmed AbdelRahim PhD PE Civil Engineering Department University of Idaho National Institute for Advanced Transportation Technology Crash Types Collision Diagrams Intersection Design Safety 0 Improvements 0 In rsection crashes as a percentage of total crashe 50 in urban areas 30 in rural areas 0 Fatal intersection crashes as a percentage of total fatal crashes 12 at signalized intersections 9 at unsignalized intersections 0 Crash frequency 15 per year at rural unsignalized intersections 25 per ear at urban unsi naIized intersections 46 per year at signalized intersections ntersection Design Safety Improvements 0 HTO Strategic Highway Safety Plan goal Reduce fatalities b 5000 to 7000 per year by the period from 200 to 2005 o 22 emphasis areas 0 Goal 17 lmprovingthe Design and Operation of Highway Intersections 17A Use automated methods to mo 39tor and enforce intersection traf c control 178 Upgrade signalized intersection controls that smooth tra lc ow 170 Utilize new technologies 17D Implement more effective access management policies Strategies for Improving Intersection 0 Safety 0 lrn rove access management nearrntersectrons close or relocate drlvevvays nearrntersectrons v rtdrlvevvays to rlghtrlrlrlghtroutoperatlon 0 Reduce frequency verlty oflntersectlon confllcts lnstalllmprove rntersectronturn lanes provlde shoulderbypass lanes at rntersectrons on tworlane hlghways restnctorelrn urns provlde excluslve turn olrases alrgn skewed rntersectron aooroacnes 0 Improve srgnt drstance on rntersectron approacnes removll39lg roadsrde srgnt oostructrons regradrng roadsrde areas Strate ies for Improving Intersection Safety 0 lrnor e drlver awareness orrntersectrons as vlevved from tne lnter ctron approacn ennanced srgnrng and delrneatron rntersectron ll ntrn splrtterrslands on rntersectron approacnes rurnole stnos on approacnes cnoose aooroonate trafflc control to rnrnrrnrze crasn frequency and severl y avold srgnalrzrng tnrougn roads use alternatlvesto srgnalrzatron rncludrng allrway STOPrcontrol 0 Improve drlver cornolrance Wlth trafflc control devlces and trafflc laws at rntersectrons eted enforcement Educatron 0 Reduce speeds on rntersectron approacnes targeted enforcement o Innovative Treatments offset leftturn lanes 0 0 set leftturn lanes laterally so that the view of a leftturning driver is not blocked by an opposing leftturning vehicle 0 can be used effectively at dividedhighway intersections 0 included in AASHTO Green Book 0 safety review in NCHRP Report 375 lnnovatIve Treatments e OFF ET RlGH VTURN LANES e sei Vlthum iahe iaieiaiivW 5e ihanhe VlEW mi 3 dllVEl EMEllng eii Elusslng ihe highway iiemi e mihei ieae l5 hm blacked by a vehicle in he majulrluad Vlthum iahe e MEDlAN ACCELERATlON LANES eah lmplqu iemiiih upeiaiieh at dividedrhighway lnlElSEElanS besl suned lei eiieeiiehai median DpEmngS hm eah W lk eiieemeiy ai hem upehhge alel Vle in NCHR P Pep Inn vative Treatments 0 CU N DABOUTS have great otential as an alternative to hi her volume ST Pcontrolled intersections whi e avoiding signalization 0 recent research indicates crash reduction effectiveness of 40 for total accidents 50 to 80 for fatal and injury accidents 0 concerns exist for visually impaired pedestrians use of roundabouts on school routes lnn vative Treatments 0 Indir ct Ie turn treatments reduces con ict points and increases operational ef ciency forthrough traf c 0 Geometric alternativesjughandle loop median Indirect Le Tum Movemenl Via Jughandle Roadway Indirecl Le Tum Movemenl via Loop Ruadvmy J Lndimct LeftTum Movement I via Median Crossovei l Inn atlve Treatments 0 TR TMENTS TO ASS ST DRWERS N JUDG NG GAPS AT UN GNAUZED NTERSECT ONS avementmarkmgs uf fuadsfde pdsfs at xed dfstanee uf ffavef ume fumthe mtefsectmn aefwe devmes e g ashmg beaennsnu feH dHVErS when ff fs nut safe m pm eed o TRAFF C CALM NG Ch 2 j ewe Reddee speeds un mtErSEEUDn apprnaches meddf added fumement z dpwenevs mmHuundabums nanuwmg Wfdm feduendn by cuvbs uvs1npmg 0 Emerging Issues sfgnafs un rura and mgher speed mghvvays Radfdad grade Erussmgs adjacenttu mtersectmns TS mpruvementsr ddanufy safety eff s Better genmem desfgnsmfdd h dfagnusncrevfewsr FHWA nfefsemdn Dfagndsffe Rewew M dddfe w mtg waw fhrc govsaf Qub502045 0 CE576 Highway Design and Traf c Safety Spring 2008 Lecture 23 Ahmed AbdelRahim PhD PE Civil Engineering Department University of Idaho National Institute for Advanced Transportation Technology 0 METAA NALYSIS Metaanalysis can be viewed as an extension of traditional narrative literature reviews It is based on a systematic review of relevant studies dealing with a the target topic It includes a comprehensive and critical review of studies It employs a standard approach to study retrieval and analysis N 0 4 39 Meta Analysis KEY ELEMENTS 0F SYSTEMATIC REVIEWS INCLUDE A systematic and extensive search for relevant studies with the objective of including all studies hat have been made even those unpublished Data extraction from each study according to a standardized procedure and Formula ion of clear study inclusion criteria with assessment of study quality PRELIMINARY DATA ANALYSIS A Defining the MetaAnalysis Topic B Systematic Literature Search C Study Inclusion Criteria 1 A signi cant period of performance for both the before and after periods to Before and after crash data in he form of crash frequency and crash rate 5quot Crash rate is calculated considering the length of road segment and AADT as exposure measure 0 DATA EXTRACTION MAIN STAGES OF META ANALYSIS 1 EXPLORATORYANALYSIS 2 MAIN ANALYSIS A FIXED EFFECT MODEL B RANDOM EFFECT MODEL 3 SENSITIVITYANALYSIS PRELIMINARY DATA ANALYSIS mu n9 I Mum u mu an my mum mum anus animuunu PRELIMINARY DATA 39 ANALYSIS peuem Ra lvnlon u and mines rim uediuueu u no mu ins euteiuue mum mun nuznvllmmn MAIN ANALYSIS FIXED EFFECT MODEL Consideration only wimin study variability Assumption Studies use identical methods treatment and measurements i i within study variation Quesuou Did d1 treatment produce bene t on average in due studies at hand RANDOM EFFECT MODEL Consideration Both between study and wimin study variability Assumption Studies are random sample from Ike universe ofall possible studies Quesuou Vill the treatment produce bene t on average 0 MAIN ANLYSISMODEL 39I a c amp quotF I If e m 33 l m INITIAL OUTLIERS OUTLIERS man or cumin l WEIENTED mm mm mi umsol maimm mne 4 StzusuzaI misinr ussii reruns mm run in EIqudziIm run 21 SEW FUNNEL GRAPH muzm FDEWRMAUQA mm Wisp wimm i smmmiwzim 2 a Fxglnr 39E sro rueuunrnuui sixin onzhtv39vbruhzy afkokuaxtrx SENSITIVITY ANALYSIS EIThe potential presence ofpublication bias EIThe Choice ofesiirnaior of e ect EIThe possible presence of outlier bias EIStatistica weighting of individual esiirnaies of e ect and DAssessment ofstudy quality SENSITIVITY ANALYSIS CONT I IIIowned IIIzu Im Iobu on cm39cw39 cm I man ch II I39oIIowS m 100 7 cIy rubu 7 01107010 Rubw NcIIII39III H mm MM w mymsmxc Avalue ofl Indicates that the results ofameta analysis are very Robust meaning that they are not at all a ected by the choices made by the analyst SENSITIVITY ANALYSIS CONT Mum mm mlmmnIhdthWhh l CE576 Highway Design and Traffic Safety Ahmed AbdelRahim PhD PE Civil Engineering Department University ofldaho National institute forAdvanced Transportation Technology Highway Design and Traffic Safety Introd uctio n Federal nghmyAdmlnlxtrztlon mm mlunn xtatement 5geand ef cient national transportation systemquot AmerlunAuoclatlon ofStat thweyenornnxoomnon omcah MSH I O munon mtement people and goods on the nation transportation systemquot loshomniooranon Department iTD munon xtatemem quotunproye the sazeg aua mooility on the state39s roadway system The city oi Moxcow imeihgemTrznxporutlen Syxtem main oblectlv an integrated tra ie signal system that improves the sum and e1 eieney1or all road user types Highway design and Traf c safety the challenge Interaction between V The users human faLtol39s r TheVelllt39le vehicle tierectemtitl Th Roadway highway design r The tonnol highway operations Our Mlsslon SaferTranspomtlon System through Better Designquot How to improve Traffic Safety 7 The Driver licensingenforcement in s HTO gm 7 The control traf c control standards 7 MUTCD Enforcement ystems 7 e Roadway highway design standards 7 ASS n book Human Factars The driving Task Three Levels i 7 A sdebasedcamml includes ssssndwsssmd 2x hang af mfamiahm and annual mpuls hawzen dds driver and ms Velma Mast mam achvmes neperfamied aummauca y mud hm smssms e m Safelmeblems U af a safe speed mdplwpd psdd Mauve ta madway and lame elements dymms mpms i i 7 A hwwledgtbasedbehawm Raul pimng and gudsnss while an mus Human Factars Driver Perfarmance o Percepdmkespnnse Time 0 Central anement Time 7 Enl39 1 dis 7 5mm mm 0 Res nnsetn Traf c Cnntrnl Devices Time and Dismiss o Respnnsetn cum Vdmicle Dynamic 7 11 value Am 7 The was a o Hzxarrl Detectinn Recugniu39nn and Identi cztinn Human Factors Individual Differences in Driver Performance 0 Gender 0 A e r LdYS Vmualtlruitv 5 and Starting in quir Tmin o D iver Impairmen 7 DnlgAlmhaluse 7 aligue r Dixrnu y39an Vehicle Characteristics 1 Brake conditions Tire conditions Crash avoidance systems Passenger survivability SUV Good and bad7 Highway Operation and Design Vertical and horizontal curves I Sight distance stopping and passing SignaITiming design Minimum green e hase Detector placement to minimize dilemma zone Approach to Safer Roads Is it an accident or a crash I Approach objectives a Redutlng actldent occurrence 39 Reduzvng accvdsnt seventy Improving crash suwwablllty Multiagency effort transportation PD CE576 Highway Design and Traf c Safety Spring 2008 Lecture 15 Ahmed AbdelRahim PhD PE Civil Engineering Department University of Idaho National Institute for Advanced Transportation Technology Innovative Treatments 0 TREATMENTS To ASSiST DRWERS N JUDGiNG GAPS AT UNSiGNALiZED iNTERSECTiONS adside posts atfixed distanee di travel time active devices e g flashing beacuriSJtu teii drivers when it is not safe td pmeeed o TRAFFiC CALMiNG obieetive Reduce speeds dn interseetidn approaches With ut added enforcement Types of strategies ve umps idNenevs mmHuundabuuts naiiuwmg Width ieducliun by Clubs di sniping Innovative Treatments 0 Emerging Issues Signals on rural and higher speed highways Railroad grade crossings adjacent to intersections ITS improvements quantify safety effects Better geometric designs through diagnostic reviews FHWA Signalized intersection information guide FHWA Intersection Diagnostic Review Module ml ht p tfnrcgovsafeg hsdmpubs02045 0 Approach to Traffic Safety o Is it an accident or a crash 19039 mu WM WM 1934 1mm Mmumm mu mmwmsmw Emlnlmndzmrhwry Synmunlicmy Behu iwxel lmxy 0 Crash Reporting 0 Who is responsible for accident reports 0 Issues to consider Consistency of de nitions Bias 7 Manual en39or Colliswn diagram Accident Reporting 0 Unreported accidents 2530 of accidents and 60 of auto involvements PD below legal reporting Should be reported but unsureunable o Collision Diagram Very reliable but can not be coded to the database Crash Reporting Bias Factors Affecting Traffic Safety Taxonomy ummumumn pummmmuumwmrm z 0 Type of Mode mum Fliurrru arm n mum
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