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24 researchers have derived the factors by statistically fitting Where models of level of service to the bicyclist-reported level of Vol 15 = volume of directional traffic in 15-minute time service. Some researchers have used both methods. period Many researchers have fitted models that predict the mean L = total number of through lanes level of service that would be reported by bicyclists. Some SPt = effective speed limit (see below) have fitted ordered cumulative logit models that predict the = 1.12ln(SPP -20) + 0.81 percentage of bicyclists who will report a given LOS grade. And SPP = Posted speed limit (mi/h) The final LOS grade is then the one for which at least 50% of HV = percentage of heavy vehicles the responses were equal to or greater than that LOS grade. PC5 = FHWA's five point surface condition rating Some researchers (particularly the FDOT-sponsored We = average effective width of outside through lane research--See Landis for example) have defined LOS A as Petritsch [36] documented the video laboratory portion of being the best and LOS F as being the worst. Others have de- the research. Seventy-five volunteers were shown video of fined LOS A as being "very satisfied" and LOS F as being "very eleven sections. The total viewing time for the video was unsatisfied" (see the Danish research reported by Jensen, 47 minutes. Comparison of the 615 LOS ratings by the video below). Zolnick and Cromley [34] developed a bicycle LOS and the field participants found that the null hypothesis that model based on the probability of bicycle/motor vehicle there was no difference in the mean ratings between the field collision frequency and severity. One pair of researchers (see and video lab participants could not be rejected at the 5% Stinson and Bhat below) sought to obtain measures of bicy- probability of a Type I error (rejecting the null hypothesis cle perceptions of quality of service by asking route choice when it is really true). questions. Their theory was that bicyclists will select the route that gives them the greatest satisfaction. Most of the research has focused on predicting bicycle level Segment LOS Models Based of service for street segments between signalized intersec- on Field Surveys or Video Lab tions. A few research projects have focused on predicting the overall arterial street level of service. Jensen [37] showed 407 people video clips of 56 roadway segments (38 rural, 18 urban) in Denmark. A total of 7,724 An Arterial LOS Model Based LOS ratings were obtained for pedestrian LOS. Another 7,596 on Field Surveys and Video Lab LOS ratings were obtained for bicycle LOS. A 6-point satis- faction scale was used (very satisfied, moderately satisfied, a Petritsch et al. [35] developed an arterial LOS model for bi- little satisfied, a little dissatisfied, moderately dissatisfied, very cyclists based on a mix of video laboratory and field surveys. dissatisfied). Jensen noted that walking against traffic, sounds LOS observations were obtained from 63 volunteers who rode other than traffic, weather, and pavement quality all affected the 20-mile course in Tampa, Florida, in November 2005. An perceptions of either bicycle or pedestrian LOS, but these LOS rating was obtained for each of the 12 sections of the variables were dropped from the model because they were not course. A total of 700 LOS ratings were obtained. The average considered useful to the road administrators who would ratings for each section rated in the field ranged from LOS B apply the models. Cumulative logit model forms were se- to LOS E. lected for both the bicycle and pedestrian LOS models. These The volunteers identified bike lanes, traffic volume, pave- models predicted the percentage of responses for each of the ment condition, and available space for bicyclists as their 6 levels of service. The single letter grade LOS for the facility most important factors for rating section LOS. The recom- was determined by the worst letter grade accounting for over mended arterial LOS model for bicyclists is as follows: 50% of the predicted responses for that letter grade and BLOS Arterial = 0.797 (SegLOS) better (For example, if over 50% responded LOS B or better + 0.131 (unsig/mile) + 1.370 (Eq. 5) and less than 50% responded LOS A, then the segment LOS was B). Where Landis et al. [38] documented a field survey of 60 bicy- SegLOS = the segment level of service numerical rating clist volunteers riding a 27-km (17-mi) course, in Orlando, (A 1.5, B 2.5, C 3.5, D 4.5, E 5.5) Florida. The course included 21 intersections, of which 19 Unsig/mile = Number of two-way stop controlled intersec- were signal controlled, 1 stop controlled, and 1 a roundabout. tions per mile (arterial does not stop). The volunteers ranged from 14 to 71 years of age (individuals SegLOS = 0.507 * ln(Vol15/lane) 13 years and under were prohibited from participating + 0.199 SPt (1 + 10.38 HV)2 + 7.066 (1/PC5)2 because of safety concerns); 34 percent of the volunteers were + -0.005 (We)2 + 0.760 (Eq. 6) female. Most of the volunteers were "experienced" bicycle

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25 riders (i.e., those riding more than 200 miles per year). Riders Wt = total width of outside through lane and bike lane (if with over 1,000 miles per year of riding experience represented present). a disproportionate share of the volunteers. CD = crossing distance, the width of the side street (in- The course consisted of roadways ranging from two to six cluding auxiliary lanes and median) lanes with average daily traffic (ADT) from 800 to 38,000 ve- Vol15 = volume of directional traffic during a 15-minute hicles per day on the day of the survey. The percentage of time period. trucks ranged from zero to 8.1. The posted speed limits L = total number of through lanes on the approach to the ranged from 25 to 55 mph. intersection. Participants were given a score card to carry with them and The researchers reported a correlation coefficient (R-square) instructed to "circle the number that best describes how com- of 0.83 against the average repored LOS for each of 18 signal- fortable you feel traveling through the intersection" immedi- ized intersections. The table below shows the author's pro- ately after crossing each subject intersection. The researchers posed correspondence between LOS letter grade and the defined Level A for the participants as "the most safe or com- scores reported by the volunteers. The authors selected the fortable." Level F was defined for the participants as "the most breakpoints. They are not based on an analysis of the reported unsafe or uncomfortable (or most hazardous)." scores. Videocameras were used to record (1) participant numbers The lowest possible score that an individual could report and time at each intersection and (2) traffic conditions at the was 1.00, so a preponderance of 1.00 responses was required actual moment when the rider crossed the intersection. Ma- for the average response to be less than 1.5. It was harder to chine road tube counters were used to collect volumes at the get LOS A or LOS F than the other levels of service, because time of the survey. Turn-move counts were also collected on A and F require more agreement among the respondents than the day of the survey. for the other levels of service. Participant starts were spaced so that bicycle-to-bicycle in- Harkey, Reinfurt, and Knuiman [39] developed a model terference would not influence the LOS ratings. for estimating bicycle level of service, based on users' percep- The letter grades were converted to numerical values (e.g., tions. The model, known as the Bicycle Compatibility Index A = 1, F = 6) (see Exhibit 32) and a hypothesis test was per- (BCI), was designed to evaluate the ability of urban and sub- formed to determine if sex had a significant effect on the urban roadways to accommodate both motor vehicles and mean LOS ratings. The mean rating for the 20 female partic- bicyclists. The study included 202 participants, ranging from ipants was 2.86. For the 39 male participants, the mean rating 19 to 74 years of age; approximately 60 percent were male. was slightly lower--2.83 (The lower rating implies better The expertise level of the participants ranged from daily com- perceived LOS). A t-test indicated that this difference was not muters to occasional recreational riders. The participants significant at the 5% Type I error level. were surveyed in Olympia, Washington; Austin, Texas; and A second hypothesis test was made for delay. The 26 riders Chapel Hill, North Carolina. The study consisted of showing having to stop for the signal gave the intersections an average participants a series of stationary camera video clips taken 2.93 rating, while the 33 not stopping rated the intersections from 67 sites in 2.94 (the higher rating implied worse perceived LOS). This dif- ference was also insignificant at the 5% Type I error level. Those Eugene and Corvallis, Oregon; stopping at a signal were delayed an average of 40 seconds. Cupertino, Palo Alto, Santa Clara, and San Jose, California; A third test was for the effect of rider experience. The Gainesville, Florida; 55 experienced bicyclists reported an average LOS rating of Madison, Wisconsin; and 2.80. The four inexperienced cyclists reported an average LOS Raleigh and Durham, North Carolina. rating of 3.42 (the higher rating implied worse perceived LOS). This difference was found to be statistically significant. Exhibit 32. However, the four inexperienced cyclists' results were in- Correspondence cluded with the experienced cyclists' results for the purpose Between LOS Grade of model development. and LOS Numerical The level of service model is as follows: Score (Landis). LOS = -0.2144Wt + 0.0153CD LOS Model Score A 1.5 + 0.0066(Vol15/L) + 4.1324 (Eq. 7) B > 1.5 and 2.5 C > 2.5 and 3.5 Where D > 3.5 and 4.5 LOS = perceived hazard of shared-roadway environment E > 4.5 and 5.5 for bicyclists moving through the intersection. F > 5.5