Table 2: Accuracy and precision of experimentations of some direct APC technologies.

Authors Location APC Technology Transit mode Vehicles Tested [#] Boarding/alighting stop-level data [#] Accuracy (Precision) evaluation method Accuracy (Precision) main results
Deibel and Wood [27] USA I, U, P, M and A Bus 2 n/a Error rate of counting (n/a) Generally, APC undercount boarding and alighting passengers; M provided an accuracy better than 98 % of passengers’ volumes; however, the maximum load is significantly less than I;
Poirier and Hobbs [28] USA I and M Bus 9 8,600 Cross tabulation of error rate of counting errors for classes (n/a) APCs are accurate i.e., no count’s errors, for 79% of the observations
Attanuccci and Vozzolo [13] USA I and M Bus n/a n/a Review of 12 case studies (n/a) M APCs are accurate, i.e., no count’s errors, for about 91.5% of the observations; Undercount boarding and alighting passengers; Boarding more accurate than alighting
Strathman [29]; [30] and Strathman and Hopper [31] USA I Bus 46 3,768 Confidence intervals and mean test (n/a) Overcount boarding and alighting passengers with statistical accuracy
Kimpel et al. [32, 33] USA I Bus n/a 2,921 Error rate of counting, Confidence intervals and mean test (Direct and Reverse regression models and t-test) Overcount boarding, alighting and loads; Boarding and alighting passengers are measured with statistical accuracy for low-floor buses. (The amount of measurement error due to APC is statistically significant)
Strathman et al. [34] USA I Rail n/a 722 Confidence intervals and mean test (n/a) Undercount boarding and overcount alighting passengers
Barabino et al. [5] Europe I Bus 1 950 Confidence intervals and mean test, mean absolute error, Root Mean Squared Error; (n/a) Undercount boarding and alighting, unlike boarding, alighting passengers are measured with statistical accuracy; low magnate errors

Representative, but not comprehensive references’ list related. APC Technology: I= Infrared beam; U = Ultrasonic beam; P = Pressure sensitive mat; M = Multi-switch treadle; A = Acoustic echo ranging system; EWE = Electronic Weighing Equipment.