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model results. The x axis of the figure represents a specific road segment and a
time period. It can be seen from the figure that the number of positive and negative
deviations are almost same for both weekday and weekend models. The maximum
deviations for weekday and weekend are 57.63% and 81.44%, respectively. This re-
sults in higher average deviation for weekend (19.65% for weekend compared to
14.90% for weekday).
Figure 6 also shows that the number of residuals with values of 15% or less
represent 62.5% and 75% of all the residuals for weekday and weekend, respectively.
It can be said that both models estimate the 85
th
percentile speed to a reasonable level
for such limited number of sample size.
The estimated values of the 85
th
percentile speed were classified according to their
corresponding current posted speed limits. A comparative descriptive analysis of the
estimated (model results) and actual (field data) values of the grouped data for both
weekday and weekend models are presented in Table 5.
It is evident in Table 5 that the mean, median, minimum, maximum and stan-
dard deviations of the estimated model results are very close to those of the actual
data in case of lower posted speed limit (40 km/hr) for both weekday and weekend
models. On the other hand, some variations on these values can be observed in
both models' results for road segments with higher posted speed limits (60 km/hr
and 80 km/hr).
40
30
20
10
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
-10
-20
-30
-40
-50
-60
-70
-80
-90
Weekday
Weekend
Fig. 6.
Percentages of deviations for both weekday and weekend FLMs
