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Publication Number: FHWA-RD-03-040
Date: July 2002

Researcher's Guide to The LTPP Layer Thickness Data

Figure 1: Layer Thickness Measurements Along the Section for AC surface and Binder Layer for the SPS-1 Section 55-0118.

Mean Standard Deviation bin bin Frequency   Expected Normal Field Observations
65.48582 6.959354666
50
50
1
46 - 50
0.716899032
1
1663.34 176.7676085
55
55
2
51 - 55
2.90984998
2
   
60
60
6
56 - 60
8.213138758
6
   
65
65
17
61 - 65
14.12963799
17
   
70
70
13
66 - 70
14.82494145
13
   
75
75
12
71 - 75
9.486755134
12
   
80
80
3
76 - 80
3.70078331
3
    More More 1 More
1.017994351
1
       
55
 
53.98200565
55

Figure 2: Example Distribution of Layer Thickness measurements along the section for PCC surface layer for the SPS-8 Section 39-0809.

Mean Standard Deviation index bin bin Frequency   Expected Normal Field Observations
199.517
7.618923653
1
181
181
1
177 - 181
0.452470252
1
5067.7318
193.5206608
2
186
186
3
182 - 186
1.828750939
3
3
191
191
3
187 - 191
5.627400247
3
4
196
196
13
192 - 196
11.42212919
13
5
201
201
19
197 - 201
15.29916715
19
6
206
206
10
202 - 206
13.5254647
10
7
211
211
7
207 - 211
7.891590078
7
8
216
216
4
212 - 216
3.037784637
4
8
More
More
0
More
0.771028733
0
60
56.04697256
60

Figure 3: Example of Normally distributed Thickness deviations.

(-44.5) - (-38.1)0
(-38.1) - (-31.8)0
(-31.8) - (-25.4)0
(-25.4) - (-19.1)1
(-19.1) - (-12.7)0
(-12.7) - (-6.4)1
(-6.4) - 03
0 - 6.47
6.4 - 12.715
12.7 - 19.110
19.1 - 25.47
25.4 - 31.82
31.8 - 38.11
38.1 - 44.51
44.5 - 50.80

Figure 4: Example of a Skewed Distribution for Layer thickness deviation.

  Frequency   
-3.750(-101.6) - (-95.3)0
-3.53(-95.3) - (-88.9)3
-3.250(-88.9) - (-82.6)0
-34(-82.6) - (-76.2)4
-2.750(-76.2) - (-69.9)0
-2.50(-69.9) - (-63.5)0
-2.250(-63.5) - (-57.2)0
-20(-57.2) - (-50.8)0
-1.751(-50.8) - (-44.5)1
-1.50(-44.5) - (-38.1)0
-1.251(-38.1) - (-31.8)1
-10(-31.8) - (-25.4)0
-0.750(-25.4) - (-19.1)0
-0.50(-19.1) - (-12.7)0
-0.251(-12.7) - (-6.4)1
012(-6.4) - 012
0.25170 - 6.417
0.5146.4 - 12.714
0.75912.7 - 19.19
1719.1 - 25.47
1.25425.4 - 31.84
1.5031.8 - 38.10
1.75038.1 - 44.50
2044.5 - 50.80
More0