FINAL REPORT. City of Toronto. Contract Project No: B

Transcription

1 Cty of Toronto SAFETY IMPACTS AD REGULATIOS OF ELECTROIC STATIC ROADSIDE ADVERTISIG SIGS TECHICAL MEMORADUM #2C BEFORE/AFTER COLLISIO AALYSIS AT SIGALIZED ITERSECTIO FIAL REPORT 3027 Harvester Road, Sute 400 Burlngton Ontaro L7 3G7 Tel.: Fax: Contract Proect o: B /09/2013

2 Table of Contents 1 Introducton 1 2 Treatment and Comparson Stes 2 3 Study Approach 4 4 Results of the Before and After Analyss 9 5 Concluson 10 Tables Table 1: Treatment Stes 3 Table 2: Comparson Stes 4 Table 3: HSM Symbols Used for the Before/After Study 5 Table 4: Predcted umber of Collsons 5 Table 5: SPF Parameters for Group 3 Sgnalzed Intersectons 6 Table 6: Safety Effectveness at Indvdual Treatment Ste 9 Table 7: Overall Safety Effectveness and Its Precson 9 Fgures Fgure 1: Electronc Statc Sgn - Sheppard Ave E and Vctora Park Ave Intersecton 2 Fgure 2: Approaches Impacted by the Electronc Statc Sgn 2 Fgure 3: Locaton of the Study Intersectons 3 CITY OF TOROTO

3 1 Introducton Lke many other ndustres, the outdoor advertsng ndustry s embracng and applyng new technologes. As technology contnues to advance, the ndustry s takng advantage of electronc sgns, some of whch are Statc Electronc Sgns (SES). SES are electronc, or dgtal sgns that use an LED dsplay and have the ablty to automatcally change the message shown on the sgn at regular ntervals. The ablty to show multple advertsement copes on a sngle sgn, along wth ther brghtness, hgh-resoluton capactes and attenton-grabbng potental s appealng to the outdoor advertsng ndustry. These sgns are usually controlled remotely and some can even dsplay fullmoton vdeos. For the purpose of ths study, only electronc sgns showng statc copes are beng consdered, and vdeo advertsng sgns are not ncluded. The advertsng ndustry s, by nature, seekng people s attenton and roadsde SES can be hghly conspcuous and compete for drvers attenton. Whle studes have proven that electronc advertsng dsplays have mpacts on drver dstracton, the actual effects of ths sgn technology on collson experence have been dffcult to prove conclusvely. As a result, many government agences are adoptng gudelnes or regulatons for SES n response to an ever-ncreasng number of nstallaton requests. The obectve of these gudelnes s to control aspects of the placement and operaton of these sgns, such as brghtness, message duraton, and message change ntervals, whch can have mpacts on the surroundng envronment and traffc. In order to gan a better understandng of the safety mpacts of SES the Cty drected CIMA to undertake a 3-part revew of electronc statc advertsng sgns, whch ncluded the followng components: 1) Revew of current research lterature; 2) Before/after collson analyss of exstng electronc sgns, ncludng: a) Transt shelter scrollng advertsng sgns b) Electronc sgns at md-block locatons (expressways and arteral roads) c) Electronc sgns at sgnalzed ntersectons; 3) Revew of best practce gudelnes and regulatons n other ursdctons. Ths techncal memo addresses component 2c), a before/after collson analyss of the mpact of electronc statc advertsng sgns at sgnalzed ntersectons. The methodology used s smlar to the comparson-group safety effectveness evaluaton method outlned n the AASHTO Hghway Safety Manual (HSM), 1 st Edton, but also ncorporates the use of Safety Performance Functons. In the sectons that follow, ths memorandum dscusses the treatment and comparson stes analyzed, explans the analyss methodology step-by-step and presents the results. CITY OF TOROTO 1

4 2 Treatment and Comparson Stes CIMA was retaned by the Cty to evaluate the mpacts of an electronc sgn nstalled n 2007 at the north-east corner of Sheppard Avenue East and Vctora Park Avenue ntersecton (Fgure 1). o other sgn exsted at ths locaton before the nstallaton of ths SES. The sgn s made of two dgtal panels, one facng north-west and the other one facng south-west. Because of ts orentaton, the sgn s vsble from three of the four ntersecton Fgure 1: Electronc Statc Sgn - Sheppard Ave E and approaches: south, west and north Vctora Park Ave Intersecton approaches. Therefore, a total of three approaches are affected by the sgn and consdered as treatment stes (Fgure 2). Legend Locaton of the electronc statc sgn Approach from whch the sgn s vsble Fgure 2: Approaches Impacted by the Electronc Statc Sgn It s assumed that all other factors that mght mpact road safety (e.g. exposure, drver behavour, drver populaton, Cty's road safety programs, traffc regulatons, etc.) have equally affected all four approaches of the ntersecton. Ths s an deal scenaro for consderng the remanng east approach of the same ntersecton, not mpacted by electronc statc sgn, as a comparson ste for conductng a before/after study usng a comparson group. To ncrease the sze of our comparson group and better account for the dfferent condtons between the before and after perod, another sgnalzed ntersecton was ncluded to the comparson group. The ntersecton has smlar characterstcs and CITY OF TOROTO 2

5 no electronc sgn was nstalled between the before and after perod. Ths results n a total of 3 treatment stes from 3 approaches and 5 comparson stes for analyss. It should be noted that the proposed methodology s consstent wth the Cty's 2004 study evaluatng the traffc safety mpacts of dgtal vdeo advertsng sgns 1. The treatment and comparson stes are located at two ntersectons: Sheppard Ave E and Vctora Park, and Sheppard Ave E and Warden Ave. Locatons of these two ntersectons are shown n Fgure 3. Fgure 3: Locaton of the Study Intersectons The before and after perods consdered n ths study were dentcal for all stes. The before perod was from January 2004 to December 2006 and the after perod from January 2008 to December Table 1 and Table 2 summarze the vehcle and pedestran volumes and number of collsons n the before and after perods, for each treatment and comparson approach. Table 1: Treatment Stes Intersecton Approach Traffc Volume (8-hour Count) Observed umber of Collsons Pedestran Maor Mnor Before After South 4,481 19,526 18, Sheppard Ave E and Vctora Park orth 4,481 19,526 18, West 4,481 19,526 18, Smley, A., Persaud, B., Bahar, G., Mollett, C., Lyon, C., Smahel, T., & Kelman, W. L. (2005). Traffc safety evaluaton of vdeo advertsng sgns.transportaton Research Record: Journal of the Transportaton Research Board, 1937(1), CITY OF TOROTO 3

6 Table 2: Comparson Stes Intersecton Sheppard Ave E and Vctora Park Sheppard Ave E and Warden Ave Sheppard Ave E and Warden Ave Sheppard Ave E and Warden Ave Sheppard Ave E and Warden Ave Approach Traffc Volume (8-hour Count) Observed umber of Collsons Pedestran Maor Mnor Before After East 1,259 20,597 3, South 3,275 20,292 17, orth 3,275 20,292 17, West 3,275 20,292 17, East 3,275 20,292 17, To determne the frequency of collsons that occurred on each approach, two felds from the Motor Vehcle Accdent (MVA) reports were used: Apparent Drver Acton and Intal Drecton of Travel. If a drver had an attrbute dfferent than Drvng Properly for the collson feld Apparent Drver Acton, t was dentfed as the at-fault drver and ts drecton of travel was used. For each of these stes, the followng data was provded by the Cty: Intersecton type (type of traffc control and road classfcaton); 8-hour pedestran volumes and 8-hour vehcle volumes (obtaned from the Cty's 2013 Sgnalzed Intersectons and Arteral Roadways etwork Screenng study); Collson data for each ntersecton and the md-block sectons of each ntersecton approach for 3 years before and 3 years after the nstallaton date; and Current Safety Performance Functons (SPFs) for sgnalzed ntersectons. A revew of the collsons on the md-block sectons of each approach of each ntersecton was undertaken to determne f any were related to the sgnalzed ntersecton or the scrollng sgns and, therefore, need to be ncluded n the analyss. A feld vst was conducted on June 14, 2013, to verfy the nformaton provded by the Cty and dentfy the approaches or drectons from whch the sgn was vsble. 3 Study Approach To evaluate the safety mpacts of the electronc statc sgn, a "before/after comparson-group usng Safety Performance Functons" study was conducted. In before/after studes, an estmate of collson frequences n the after perod s compared wth a predcton of the collson frequences n the same perod f the treatment had not been mplemented. The before/after study wth comparson group methodology also uses SPFs to take nto account the non-lnear effects of changes n traffc volume on collson frequency. Table 3 provdes the symbols used for the observed number of collsons n accordance wth the HSM notaton. CITY OF TOROTO 4

7 Table 3: HSM Symbols Used for the Before/After Study Before Treatment After Treatment Treatment Ste observed T,B, observed T,A, Comparson Group observed C,B, observed C,A, The subscrpt denotes stes, =1,,n, where n s the number of treatment stes and the subscrpt denotes stes, =1,,m, where m s the number of comparson stes. Step 1 Predct the umber of Collsons The frst step s to estmate the predcted collson frequences usng the applcable SPFs for each treatment and comparson ste, and for both the before and the after perod. The predcted number of collsons s calculated for four dfferent groups. The HSM symbol notaton for predcted collsons s shown n Table 4. Table 4: Predcted umber of Collsons Before Treatment After Treatment Treatment Ste predcted T,B, predcted T,A, Comparson Group predcted C,B, predcted C,A, For ths analyss, each treatment and comparson ste corresponds to an ntersecton approach or drecton. However, because SPFs can only predct the total number of collsons at an ntersecton, the number of predcted collsons assocated wth each approach needs to be estmated. To estmate the number of collsons for each approach, collson dstrbutons at ntersectons (proporton of at-fault collsons assocated wth each approach) must be appled to the number of predcted collsons for each ntersecton. As a result, the followng three proportons are to be estmated: Proporton of collsons at each approach for the comparson and treatment stes n the before perod,p B,d ; Proporton of collsons at each approach for the comparson stes n the after perod,p C,A,d ; Proporton of collsons at each approach for the treatment stes n the after perod, P T,A,d. The subscrpt d denotes the approach drecton (eastbound, westbound, southbound and northbound). The Cty has recently updated ts SPFs for sgnalzed ntersectons, based on data, for ther network screenng. Table 5 present the SPF parameters for both Property Damage Only (PDO) and Fatal/Inury collsons for 4-legged Arteral/Arteral (Group 3) sgnalzed ntersectons. The functonal form of the SPF for ths group s: ( predcted ) ntersecton (Collson/Year)= exp (ntercept) (MaVOL) B1 (MnVOL)exp (B3*PEDVAR) Equaton 1 CITY OF TOROTO 5

8 Where, MaVOL = 8 hour traffc count on maor road; MnVOL = 8 hour traffc count on mnor road; PEDVAR = equal to 1 f 8 hour pedestran volume at ntersecton s greater than 1000; 0 otherwse; ntercept, B1, B2, B3, B4, B5 are estmated parameters; and k = the overdsperson parameter estmated durng SPF calbraton. Table 5: SPF Parameters for Group 3 Sgnalzed Intersectons Intercept B1 B2 B3 K PDO Fatal/Inury Once the predcted total number of collsons s calculated for each group of stes, the number of predcted collsons for each approach can be calculated for both the treatment and comparson stes. Ths can be performed by multplyng the number of predcted collsons at an ntersecton by the approprate proporton of collsons for each drecton, as follows: ( predcted T,B, ) approach= ( predcted,t,b, ) ntersecton x P B,d Equaton 2 ( predcted C,B, ) approach = ( predcted,c,b, ) ntersecton x P B,d Equaton 3 ( predcted T,A, ) approach = ( predcted,t,a, ) ntersecton x P T,A,d Equaton 4 ( predcted C,A, ) approach = ( predcted C,A, ) ntersecton x P C,A,d Equaton 5 Step 2 Calculate Adustment Factors The adustment factors are calculated to take nto account the dfferences n traffc volumes and number of years between the treatment and comparson stes durng the before and after perod. The equaton to calculate the adustment factors durng the before perod s as follows: Ad,,B Y,T,B B,T, predcted Equaton 6 predcted,c,b YB,C, Where, Y = duraton (years) of the before perod for each treatment ste ; and, B,T, Y = duraton (years) of the before perod for each comparson ste. B,T, The equaton to calculate the adustment factors durng the after perod s as follows: Ad Y predcted,t,a A,T, Equaton 7,,A predcted,c,a YA,C, Where, CITY OF TOROTO 6

9 Y = duraton (years) of the after perod for each treatment ste ; and, A,T, Y = duraton (years) of the after perod for each comparson ste. A,T, Step 3 - Calculate the Expected Collson Frequency at Each Comparson Ste In ths step, an expected average collson frequency at each comparson ste s calculated by multplyng the prevously calculated adustment factors (Step 2) by the observed number of collsons n the before and after perods. The equaton to estmate the expected number of collsons n the before perod s as follows: expected,c,b observed,c,b Ad Equaton 8,,B The equaton to estmate the expected number of collsons n the after perod s as follows: expected,c,a observed,c,a Ad Equaton 9,,A Step 4 - Calculate the Total Comparson-Group Expected Average Frequency After calculatng the expected collson frequency at each comparson ste, the total comparsongroup number of expected collsons n the before and after perods s evaluated. Ths s performed by summng the number of expected collsons at comparson stes n the before and after perod, as shown by the followng equatons. Equaton 10 m expected,c,b,total 1 m expected,c,a,total 1 expected,c,b Equaton 11 expected,c,a Step 5 - Calculate the Expected Collson Frequency for a Treatment Ste In ths step, the expected collson frequency for each treatment ste n the after perod, had no treatment been mplemented, s calculated. Ths s performed by multplyng the number of observed collsons at each treatment ste n the before perod by a comparson rato. The comparson rato s the rato of the comparson-group expected collson frequency n the after perod ( comparson-group expected average collson n the before perod ( followng equaton: expected,c,b, total expected,c,a, total ) to the ), as shown by the expected,c,a,total r Equaton 12,C expected,c,b,total Then, to obtan the expected collson frequency for each treatment ste n the after perod, the followng equaton s used: expected,t,a, r Equaton 13 observed,t,b,,c Step 6 - Calculate the Safety Effectveness for Each Treatment Ste Wth both the expected collson frequency of treatment stes and the expected collson frequency had no treatment been mplemented calculated, the safety effectveness at each treatment ste, CITY OF TOROTO 7

10 expressed as an odds rato, OR, can be estmated. The odds rato s obtaned from the followng equaton: observed,t,a, OR Equaton 14 expected,t,a, Step 7 - Calculate the Overall Safety Effectveness The overall safety effectveness of a treatment takes nto account the safety mpact observed at each treatment ste and provdes an ndcaton of whether the treatment has resulted n an ncrease or decrease n collson frequency. The overall safety effectveness s calculated as follows: Safety Effectveness = 100 (1 R) Equaton 15 Where, R = weghted average log odds rato across all n treatment stes The weghted average log odds rato s calculated usng the followng equaton: w ln(or ) R Equaton 16 w Where: w 1 observed, T, B, 1 observed, T, A, 1 1 expected, C, B, 1 Expected, C, A, Equaton 17 Step 8 Assess the Statstcal Sgnfcance The last step s to determne whether the safety mpact measured s statstcally sgnfcant. Ths s obtaned by calculatng the standard error, SE (Safety Effectveness), as follows: SE (SafetyEffectveness) 100 OR w n The rato of the standard error over the safety effectveness can then be compared to dfferent statstcal values. Dependng on the value of ths rato, one of the followng two conclusons can be drawn: If Abs [Safety Effectveness/SE(Safety Effectveness)] at the 95 percent confdence level < 2.0, the treatment effect s not sgnfcant If Abs[Safety Effectveness/SE(Safety Effectveness)] 2.0, the treatment effect s sgnfcant at the 95 percent confdence level CITY OF TOROTO 8

11 4 Results of the Before and After Analyss The results obtaned for the before/after study wth comparson-group are summarzed n Table 6 and Table 7. Table 6 provdes the results related to the safety effectveness at each treatment ste, and Table 7 presents the overall safety effectveness of nstallng an electronc statc sgn at the ntersecton of Sheppard Ave East and Vctora Park Avenue. Table 6: Safety Effectveness at Indvdual Treatment Ste Approach South orth West Predcted Collson n the After Perod Expected Collson Frequency n After Perod Wthout Treatment Observed Collson Frequency n After Perod Odds Rato Log Odds Rato Standard Error of Log Odds Rato Table 7: Overall Safety Effectveness and Its Precson Descrpton Result Weghted Average Log Odds Rato (R) 0.03 Overall Effectveness (OR) 1.03 Safety Effectveness 3.3% ncrease Standard Error (SE) Safety Effectveness / SE 0.3 Sgnfcant (at 95% confdence level) o - To be sgnfcant the Safety Effectveness / SE must be greater than 2.0 The results show that there was a 3.3% ncrease n the number of collsons after nstallng the electronc sgn and that the ncrease s statstcally nsgnfcant at the 95% confdence level. In other words, there s not enough evdence to suggest that ths sgn has any mpact on safety. Ths before/after study analyzed the mpact of an electronc statc sgn at only one ntersecton, whch consttutes a small sample sze. Despte the sample sze, the results are stll statstcally vald but should be treated wth cauton. CITY OF TOROTO 9

12 5 Concluson The Cty was nterested n evaluatng the mpacts of electronc statc advertsng sgns at sgnalzed ntersectons on road safety. A before/after study was conducted usng comparson groups and Safety Performance Functons, followng methods outlned n the AASHTO Hghway Safety Manual. An electronc statc sgn made of two panels was nstalled n 2007 at the ntersecton of Sheppard Ave E and Vctora Park Ave. The sgn s vsble from three of the four ntersecton approaches. Therefore, three approaches are affected by the sgn and consdered as treatment stes. Three years of before data, from January 2004 to December 2006, and 3 years of after data, from January 2008 to December 2010, were used. To ncrease the sample sze and better account for the dfferent condtons between the before and after perod, another sgnalzed ntersecton wth smlar characterstcs but where no electronc sgn was nstalled, was consdered as comparson ste. Ths resulted n a total of 3 treatment stes and 5 comparson stes for analyss The results of the before and after study shows that there s not enough evdence to suggest that ths electronc statc sgn has had any mpact on road safety at the sgnalzed ntersecton wth 95% confdence. Due to the fact that ths study analyzed the mpact of an electronc statc sgn at only one ntersecton, the results of the study should be treated wth cauton. CITY OF TOROTO 10