Level of service (los) multilane hwys 02 (transportation engineering)

1. LOS Analysis of Multilane
Highways

2. Key Differences B/W Freeways and
Multilane Highways
Vehicles access; no full access control for
multilane highways
Multilane highways may or may not be
divided
Traffic signals may be present
Design standards, e.g. speeds are lower as
compared to freeways
More distraction along the multilane highway

3. Multilane Divided Highways

4. Multilane Undivided Highways

5. Base Conditions for Multilane Highways
LOS Analysis
12 ft lane width
12 ft min total lateral clearance from road
side objects (right shoulder and median)
Only passenger cars in traffic stream
No direct access points
Divided highways
Level terrain
Familiar drivers
FFS of 60 mph or more

6. FFS
• FFS = BFFS – fLW - fLC - fM - fA
• BFFS ;
– 7 mph + posted limit of 40 to 45 mph
– 5 mph + posted limit of 50 mph or higher
• fLW = Lane width adjustment factor (Same as
freeways)
• fLC = Lateral clearance adjustment factor

7. fLC Lateral clearance adjustment factor
• TLC = LCR + LCL
• TLC = Total Lateral Clearance
• LCR = Right side lateral clearance to obstruction
• LCL= Left side lateral clearance to obstruction
• For undivided highways: LCL= 6 ft
• If lateral clearance on any side exceeds 6 ft, it is
taken as 6 ft.

8. FFS and Capacity on Multilane Highways

9. Adjustment for Lateral Clearance - TLC

10. Adjustment for Median Clearance - fM

11. Two Way Left Turn Lane (TWLTL)

12. Adjustment for Access Point Frequency - fA

13. Example

14. Example
FFS = BFFS – fLW - fLC - fM - fA

15. FFS
• FFS = BFFS – fLW - fLC - fM - fA
• BFFS ;
– 7 mph + posted limit of 40 to 45 mph
– 5 mph + posted limit of 50 mph or higher
• fLW = Lane width adjustment factor (Same as
freeways)
• fLC = Lateral clearance adjustment factor

16. Example
FFS = BFFS – fLW - fLC - fM - fA

17. Example
fLW

18. Example
FFS = BFFS – fLW - fLC - fM - fA

19. Example

20. Adjustment for Lateral Clearance - TLC

21. Adjustment for Median Clearance - fM

22. Example
FFS = BFFS – fLW - fLC - fM - fA

23. Adjustment for Access Point Frequency - fA
2 access points per mile

24. Example
FFS = BFFS – fLW - fLC - fM - fA

25. Example

26. Determination of ET and ER

27. 52
1500.3
Figure 6.4

28. Density
D = vp / S
• FFS = 52 mph
• Flow Rate = 1500.3 pc/hr/ln
• Average Passenger Car Speed (S) = 52 mph
• Density (D) =
= Flow Rate (pc/h/ln) / Average Passenger Car
Speed = 1500.3/52 = 28.85 pc/mi/ln

29. 52
1500.3
LOS-D