MTO TRAFFIC MODEL
The following presentation contains references to Figures 6.02 and
6.03, Tables 6.01 and 6.04, all of which are posted under
subsection 2.6 of the course notes on the instructor’s website.
Viewer discretion is advised as some scenes contain material of a
graphic, tabular and mathematical nature and are intended for
mature audiences.
MTO TRAFFIC MODEL
What does it do?
Enables you to estimate the number of passes
of a standard unit (ESAL) over a pavement
during a specific design period.
What information do you need?
Analysis Period, Ap
AADT in first year of Ap
Annual Percent Traffic Growth Rate
Number of Traffic Lanes & Directions
Percent Trucks in Initial & Final Year of Ap
Total ESAL’s, Nf Over Analysis Period
ESAL’s/day
The MTO uses a trapezoidal representation of
the total accumulated ESAL’s over the analysis
period
Initial
ESAL’s/day
Final
ESAL’s/day
Average ESAL’s/day
or DTN
Nf is the area of the trapezoid =
number of days in Ap x DTN
Time
Analysis Period, Ap
Initial Year
Middle Year
Final Year
Accumulated ESAL’s, N
The MTO uses a parabolic model to determine
the accumulated ESAL’s after Y years of the
analysis period
The Equations
Factor days out of equation 2
N f  Ap  days 
AADT  0.5  T  LDF  TF  AADT
i
i
i
i
f
 0.5  T f  LDF f  TF f 
2
N f  Ap  days  DTN
EXAMPLE
The initial AADT for a 4-lane road is
12500 vpd and is expected to grow
over the next 20 years at the rate of
3.5%/year. If the percent trucks is
expected to increase from 10%
initially to 15% at the end of the
analysis period. Find the
accumulated ESAL’s after 12 years
of traffic.
Truck Factor, TF
40% HCT
OK, now pull out your copy
of
Table
6.04
30% HCT
1.5
TABLE 6.01
Parameter/Calculation
MTO LANE DISTRIBUTION FACTORS
Description
0.97
Lane Distribution
Analysis
Period
Highway Type
2 lanes
0.5
AADT (vpd)
Factor, LDF
Traffic
All Growth Rate (%/year)
1.00
Final
0.85
4 lanes
15000 - 25000
> 25000


4
20
4
3.5 
? .36
24,872
 24,872.36
100 
0.5
8000
T
0.10
0.15
LDF
0.80
?
?
0.75
TF
?
0.77
?
0.97
ESAL/day
385
?
1357.098
?
0.70
FIGURE
- MTO TRUCK FACTORS:0.55
4-LANE HIGHWAYS
150006.03b
- 25000
Daily Total ESAL's/day
0.45
= AADT x DF x T x LDF x TF
3.5%
0.5
Traffic/Lane
(= AADT/4 for 4-Lane 0.60
Highways)
< 15000
> 40000
TGR
DF
3000
4000
5000Total Traffic
6000
7000
Truck Fraction
of
6 Truck
lanes
Factor: ESAL's/truck (Figure 6.03)
25000 - 40000
0.50
20
AADT
12,500
AADT
f  12,500  1 
0.75Split
Directional
Lane Distribution Factor (Table 6.01)
AP
Lanes
Number of Traffic Lanes
< 5000
- 15000
0.80
Average Annual5000
Daily
Traffic, two directions
0.0
2000
Initial
(After: "Pavement Design and Rehabilitation Manual", 1990)
1.0
0.77
Parameter
10% HCT
Designation
20% HCT
12
24
,
,
500
872
.
36
ESAL
 24,872.36  0.05.3125
0.015

0.097
1357
ESAL
5
.10 0.0.75
.80
.77 
385.098
AADT
/ lane
6218
09
f /i day
i / day 12,500 
44
Bring it on home!
Parameter/Calculation
Description
Daily Total ESAL's/day
= AADT x DF x T x LDF x TF
Parameter
Designation
Initial
Final
ESAL/day
385
1357.098
Days per year for truck traffic
days
300
Design Traffic Number for Design Period =
[(ESAL/day)i + (ESAL/day)f]/2
Total ESAL's over Analysis Period, Ap
= DTN x Days x Ap
DTN
871.0490929
?
Nf
5,226,295
?
Design Period, years
Y
12
Total ESAL's over Design Period,
Equation 1, Figure 6.02
N
2,720,529
?

 2
5,226,295 
2  12,500
24,872.36  12,500


Y 
N
Y  

20
 20  12,500  24,872.36  
 12,500  24,872.36 
N


385  1357.098
DTN 
 871.0490929




2
N

871
.
0490929

20

300

5
,
226
,
294
.
55735706

5
,
226
,
295
f
 261,314.75 0.668943558
Y  0.016552822 Y
2
N  174,804.819Y  4,325.49657Y 2
N  174,804.81912  4,325.4965712  2,720,529
2
