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From page 31... ... NCHRP 07‐19(02) Final Report 31 Chapter 3: Combined Findings from Phases 1 and 2 A major component of the research involved field testing a variety of commercially available pedestrian and bicycle counting technologies by comparing the counts produced by the technologies with manual counts taken from video footage. Read the entire page →
From page 32... ... Figure 3‐ The graph example, adjusted intended multiuse tubes ove Figure 3‐ 1. Exam ical analysi the pneuma after the firs for a mixed path site. Pr rcounted, bu 2. Befor Adjus ple of a Gra s also shows tic tubes on t two days o traffic situat ior to the adj t overall cou e and After tment phical Displ patterns in the Midtown f data collect ion, which re ustment, the nt accuracy Comparison 32 ay of Count the data in te Greenway i ion during P quires diffe tubes unde improved. Read the entire page →
From page 33... ... NCHRP 07‐19(02) Final Report 33 Accuracy Calculations Four accuracy and precision measures were calculated for each technology. Read the entire page →
From page 34... ... NCHRP 07‐19(02) Final Report 34 By taking the absolute values, over and undercounts of the same magnitude no longer balance each other out, but rather both count toward the total accuracy. Read the entire page →
From page 35... ... NCHRP 07‐19(02) Final Report 35 ߤ௜ ൌ ܣ௜݁ఈ೔ାࢼࢄ࢏ ൌ ܣ௜݁ఈ೔Π௞݁ఉೖ௑ೖ೔ That is, the rate is assumed to vary linearly with the automated count. Read the entire page →
From page 36... ... overcoun eliminate Based on motor ve understa character the detec passes th either mo where th In additio repeater the repea Accuracy In Figure count of b truth to b encroach apparent One outli automate would be removing (a) Bicy Figure 3‐ t, when in fa these error this experie hicles are lik nding of the istics of the tion zone. Read the entire page →
From page 37... ... NCHRP 07‐19(02) Final Report 37 Table 3‐1. Accuracy and Consistency Values for Radar Sensor Dataset APD AAPD WAPD r N Average Hourly Volume Bicyclists 256% 261% 18% 0.89 32 70 Bicyclists (no outlier) Read the entire page →
From page 38... ... the direct the data c than the b bounding sources o differenti Accuracy The therm The obse r=0.912 w Figure 3‐ Regressi Based on with the c there app multiplic develope AIC, and h ion specified ollector to m icycle or pe boxes that w f error. Futu ate bicyclist and Consis al imaging rved accurac ith a sampl 4. Accur on Correctio visual inspe aveat that th ears to be li ative factor. Read the entire page →
From page 39... ... NCHRP 07‐19(02) Final Report 39 Table 3‐2. Correction Functions for Active Infrared Sensor Intercept Night Rain AIC ‐0.0263 (0.163) Read the entire page →
From page 40... ... NCHRP 07‐19(02) Final Report 40 sinking a wooden post into the ground adjacent to the facility being counted, as is common when used as part of a combination sensor unit. Read the entire page →
From page 41... ... Figure 3‐ The fact t technolog installatio However counts ov obtained correctio needed to correctio Device‐Sp Evaluatin these tech calculate 5. Accur hat the prod y plays an im n are impor , as can be in er a variety from any of n factor need adjust the o n factors. ecific Accur g accuracy a nologies, bu separate fac (a) Read the entire page →
From page 42... ... NCHRP 07‐19(02) Final Report 42 Table 3‐3. Accuracy and Consistency Metrics on a Site‐ and Device‐Specific Basis for Passive Infrared Sensors Site Product APD AAPD WAPD r N Average Hourly Volume Overall Average ‐ −10% 17% −11% 0.96 392 261 Overall Product A A −1% 12% −4% 0.98 238 284 L St A −2% 10% −3% 0.94 39 537 Four Mile Run A 2% 8% 3% 0.90 42 171 Fell Street A −5% 10% −3% 0.97 26 43 15th Avenue A −5% 5% −4% 0.99 16 367 Key Bridge A −12% 13% −13% 0.99 48 393 Berkeley A −14% 14% 14% 0.96 6 151 Sycamore A 14% 15% 12% 0.99 24 160 Loyola A −18% 19% −18% 0.86 12 64 Overall Product B B −26% 26% −27% 0.98 115 263 Midtown Greenway B −26% 26% −27% 0.97 24 436 Four Mile Run B −21% 22% −21% 0.91 42 171 Key Bridge B −29% 29% −30% 0.98 31 351 Sycamore B −33% 33% −31% 0.85 18 96 Overall Product C C −14% 14% −14% 0.99 39 113 Four Mile Run C −14% 14% −14% 0.99 39 113 Notes: APD = average percentage deviation, AAPD = average of the absolute percent difference, WAPD = weighted average percentage deviation, r = Pearson's Correlation Coefficient, N = number of detectors, Average volume = hourly average pedestrian and bicycle counts based on video observation. Correction Functions The various correction function forms that were tested for passive infrared counters are presented in Table 3‐4. Read the entire page →
From page 43... ... NCHRP 07‐19(02) Final Report 43 greater degrees of undercounting, as the adjustment factor is positive. Read the entire page →
From page 44... ... Worse pe distinguis There is m 3‐6, there than in th temperat problem most of th difficult t On the ot at very hi very cold attributed current r enough c recomme winter te Figure 3‐ Worse pe The data Figure 3‐ rformance at hing people f inimal evid are limited e overall da ures above 9 is that high t e data in th o conclusive her hand, th gh volumes. temperatur to heavily i esearch beca lothing to ha nded that pr mperatures 6. Passiv rformance in collected by 7. Read the entire page →
From page 45... ... Figure 3‐ However observed detection However undercou The testin whether operate b Active I Qualitati The testin device ap with prev The activ transmitt 7. Accur Range , during peri . On the surf s on passive , in the regre nting, as inc g was not a snow affects y detecting b nfrared ve Experien g only inclu peared to fu ious experie e infrared se er and recei acy Compar ods of rain, n ace, this wou infrared sen ssion analys luding the ex ble to captur device perfo ody heat. Read the entire page →
From page 46... ... Accuracy The activ 3‐8. In pa WAPD = ‐ hours of d Figure 3‐ Regressi Based on again wit finding, th simple m were test fit was w Table 3‐5 In 0.079 0.0 0.079 0.09 Notes: AI a 9 Ni and Consis e infrared se rticular, volu 7.62%, r = 0 ata. Read the entire page →
From page 47... ... NCHRP 07‐19(02) Final Report 47 Effects of Different Conditions Because only one active infrared sensor was tested in the research, there was not enough variation in the data to ascertain whether any site‐level factors have an impact on the accuracy. Read the entire page →
From page 48... ... two sets o tubes we longer pr inaccurat occasiona However counting. overall da Figure 3‐ Accuracy Figure 3‐ Figure 3‐ C with bic and site, a f pneumatic re damaged operly funct e counts is t lly occluded , this does no The data fro ta plot in Fi 9. Accur and Consis 10 plots accu 11 plots accu ycle‐specifi nd Table 3‐ tubes, one i during the p ional when t hat 15th Ave the camera t seem like t m these sen gure 3‐10) Read the entire page →
From page 49... ... Figure 3‐ The pneu counter t work. It c accuracy Universit were test tubes we sometime tubes or n crossed c 10. Accur matic tube d echnologies. Read the entire page →
From page 50... ... Figure 3‐11. Accuracy Plot for Pneumatic 50 Tubes by Pr N oduct CHRP 07‐19(02) Final Report Read the entire page →
From page 51... ... Figure 3‐12. Accuracy Plot for Pneumatic 51 Tubes by Pr N oduct and S CHRP 07‐19 ite (02) Final Report Read the entire page →
From page 52... ... NCHRP 07‐19(02) Final Report 52 Table 3‐6. Accuracy and Consistency Values for Pneumatic Tubes by Product and Site Site Product APD AAPD WAPD r N Average Volume Overall Average ‐ −14.0% 16.6% −14.1% 0.986 259 166 Bicycle‐specific tubes −14.0% 16.6% −14.0% 0.986 242 173 Overall Product A A −9.5% 10.8% −11.1% 0.993 172 203 University A 0.5% 1.2% 0.6% 0.998 17 206 Key Bridge A −11.1% 11.3% −12.4% 0.981 48 97 L Street A −6.7% 10.8% −10.4% 0.991 45 62 Fell Street A −20.2% 20.2% −23.1% 0.987 23 248 Clarendon A −21.1% 21.1% −22.9% 0.999 3 23 Milton A −7.7% 7.7% −9.2% 0.997 36 503 Overall Product B B −52.6% 52.6% 39.9% 0.970 28 99 University B −34.3% 34.3% −34.8% 0.805 11 199 Eastbank B −64.4% 64.4% 59.4% 0.781 17 34 Overall Product C C −7.3% 16.6% −9.4% 0.920 43 76 Four Mile C 8.9% 9.2% 7.6% 0.996 22 75 15th Street NW C −24.2% 24.2% −26.6% 0.976 20 81 Oakland C −28.6% 28.6% −28.6% 1 14 Standard Tubes C −15.2% 17.1% −17.9% 0.936 17 62 Oakland C −15.2% 17.1% −17.9% 0.936 17 62 Notes: APD = average percentage deviation, AAPD = average of the absolute percent difference, WAPD = weighted average percentage deviation, r = Pearson's Correlation Coefficient, N = number of detectors, Average volume = hourly average pedestrian and bicycle counts based on video observation. Effects of Environmental Conditions Frozen tubes The research team hypothesized that pneumatic tubes will become less sensitive in very cold temperatures, as the rubber in the tubes hardens. Read the entire page →
From page 53... ... NCHRP 07‐19(02) Final Report 53 specific tubes was left installed on the Midtown Greenway for the duration of the study (~5 months) Read the entire page →
From page 54... ... NCHRP 07‐19(02) Final Report 54 Radio Beam Qualitative Experience The research team faced significant difficulties evaluating the accuracy of one of the radio beam sensors. Read the entire page →
From page 55... ... Figure 3‐ Table 3‐8 Dataset Overall Average Four Mil Midtown 5th Aven Notes: AP de Effects of The prim as is the c lighting, a variation radio bea between 13. Accur . Accur Pro e Run ue D = average perc viation, r = Pearso Environme ary hypothe ase with all nd rain wer in the weath m sensors in modes. acy Plot for acy and Con duct AP ‐ −10 B −6. Read the entire page →
From page 56... ... Inductiv Qualitati Inductive Both perm When eva addresse always co which is l and insta eliminate First, con 14. The lo is located located in maneuve the loop s Fell Stree also be co Figure 3‐ Second, c Minneapo zones. Read the entire page →
From page 57... ... frequentl estimatin difficult t Finally, co Arlington The path path. Hen Figure 3‐ Accuracy Figure 3‐ volume a plots rep Midtown of nearly lower vol volume a slightly a y at high vol g the accura o determine nsider the e , Virginia, sh has a constr ce, this site 15. Induc and Consis 16 compares nd the overa resent two s Greenway d 800 bicyclis umes, the fa ppears to inc ffected. Read the entire page →
From page 58... ... Figure 3‐ Table 3‐9 (i.e., cons table, ind substanti Table 3‐9 Notes: AP de Dataset All data All surfa Loyola Universit All embe Sycamor Clarendo Key Fell (a) Detect 16. Accur provides the idering only uctive loop s al difference . Read the entire page →
From page 59... ... NCHRP 07‐19(02) Final Report 59 Table 3‐10 presents accuracy and consistency statistics for inductive loops when considering facility volumes (i.e., including bypasses) Read the entire page →
From page 60... ... NCHRP 07‐19(02) Final Report 60 For these installations, site‐specific correction factors should be developed to account for bypass errors and to improve the estimation of facility volumes. Read the entire page →
From page 61... ... Figure 3‐ Both of th consisten are some are prom Table 3‐1 Product Overall Product Product Notes: AP de co Effects of While the precipita condition Regressi As noted are neede tested bu 17. Accur e piezoelect cy over the r what limited ising for this 1. Accur AP −4.0 A −3.4 B −5.2 D = average perc viation, r = Pearso unts based on vid Environme re was limit tion on accur s. Read the entire page →
From page 62... ... NCHRP 07‐19(02) Final Report 62 have an intercept value of 0.0415 (95% CI: 0.024, 0.059) Read the entire page →
From page 63... ... Figure 3‐ Figure 3‐ The insta due to oc 18. Accur 19. Accur Count llation at the clusion effec acy Plot for acy and Con ers Compar Key Bridge ts) with a hi Pedestrian sistency Plo ing Two Pro site, on the o gh rate of co 63 Volumes Es ts for Pede ducts ther hand, s nsistency, as N timated fro strian Volum hows net un indicated in CHRP 07‐19 m Combina es from Co dercounting Table 3‐12. Read the entire page →
From page 64... ... NCHRP 07‐19(02) Final Report 64 Table 3‐12. Accuracy and Consistency Metrics for Pedestrian Volumes from Combination Counters Regression Corrections Table 3‐13 shows the correction functions developed for pedestrian volume estimates using combination counters. Read the entire page →
From page 65... ... NCHRP 07‐19(02) Final Report 65 SUMMARY Table 3‐14 provides a combined comparison of accuracy and consistency values by site, product, and counting technology. Read the entire page →
From page 66... ... NCHRP 07‐19(02) Final Report 66 Technology Subset APD AAPD WAPD r N Average Hourly Volume Inductive Loops All data 0.6% 8.9% 7.6% 0.994 108 128 Surface loops 0.3% 7.6% 5.7% 0.997 29 145 Embedded loops 0.6% 9.4% 8.4% 0.993 79 122 Sycamore 7.9% 8.2% 7.7% 0.973 18 81 Loyola 7.9% 10.8% 9.8% 0.974 12 51 Clarendon −27.4% 27.4% 29.7% 1.000 3 25 Key 8.0% 8.1% 6.0% 0.996 31 92 University −5.0% 5.3% 5.0% 0.988 17 211 Fell −9.5% 9.5% 9.5% 0.998 27 194 All data* Read the entire page →
From page 67... ... NCHRP 07‐19(02) Final Report 67 for the technologies tested. Read the entire page →

From page 31...

... NCHRP 07‐19(02) Final Report 31 Chapter 3: Combined Findings from Phases 1 and 2 A major component of the research involved field testing a variety of commercially available pedestrian and bicycle counting technologies by comparing the counts produced by the technologies with manual counts taken from video footage.