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CAPACITY AND LOS in traffic

this paper explains about capacity and los of traffic movement specially in indonesian country.

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CAPACITY AND LOS in traffic

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  1. CAPACITY AND LEVEL-OF-SERVICE CONCEPTS

  2. CAPACITY The capacity of a facility is the maximum hourly rate at which persons or vehicles reasonably can be expected to traverse a point or a uniform section of a lane or roadway during a given time period under prevailing roadway, traffic, and control conditions. Vehicle capacity is the maximum number of vehicles that can pass a given point during a specified period under prevailing roadway, traffic, and control conditions. This assumes that there is no influence from downstream traffic operation, such as the backing up of traffic into the analysis point. Person capacity is the maximum number of persons that can pass a given point during a specified period under prevailing conditions. Person capacity is commonly used to evaluate public transit services, high-occupancy vehicle lanes, and pedestrian facilities.

  3. Prevailing roadway, traffic, and control conditions define capacity; these conditions should be reasonably uniform for any section of facility analyzed. Any change in the prevailing conditions changes the capacity of the facility. Capacity analysis examines segments or points (such as signalized intersections) of a facility under uniform traffic, roadway, and control conditions. These conditions determine capacity; therefore, segments with different prevailing conditions will have different capacities.

  4. In the HCM 2000, demand is the principal measure of the amount of traffic using a given facility. • Demand relates to vehicles arriving; volume relates to vehicles discharging. If there is no queue, demand is equivalent to the traffic volume at a given point on the roadway. • Throughout this manual, the term volume generally is used for operating conditions below the threshold of capacity.

  5. LEVEL-OF-SERVICE CONCEPTS Level of service (LOS) is a quality measure describing operational conditions within a traffic stream, generally in terms of such service measures as speed and travel time, freedom to maneuver, traffic interruptions, comfort and convenience

  6. FACTORS AFFECTING CAPACITY AND LOS IHCM 1995

  7. MKJI 1997

  8. CALCULATION PROCEDURE FOR URBAN ROADS STEP A : GENERAL DATA STEP B : GEOMETRIC CONDITIONS STEP C : TRAFFIC CONDITIONS STEP D : ANALYSIS STEP E : RE-ANALYSIS (optional)

  9. STEP A : GENERAL DATA

  10. STEP B : GEOMETRIC CONDITIONS

  11. STEP C : TRAFFIC CONDITIONS

  12. STEP D : ANALYSIS STEP E-2 STEP E-3 STEP E-4 STEP E-1 STEP E-5 STEP E-6

  13. 4 + 6 + 3 = 13

  14. DATA

  15. This is part of data that different from example 1

  16. STEP C : TRAFFIC CONDITIONS (STEP A AND STEP B ARE SAME WITH EXAMPLE 1) FROM THE MANUAL DATA

  17. See Example 1 DS = Q/C

  18. EXERCISE • Road type : Four lane two-way traffic • Geometry : 10,0 m effective carriageway width 1,5 m effective shoulder on right side (level with road) 1,5 m distance obstruction from the curb on left side • Traffic : Directional split of 65 - 35 • Environment : City size 1.200.000 inh. Many minibus, some pedestrians some traffic using roadside accesses. • A peak hour volume is determined from below data and, but for LV only times with your last ID Number Q (LV = 150; HV = 80; MC = 1800; and UM = 40) veh/hr for example: ID D100 013 002  New QLV = 300 veh/hr QUESTION • Please determine what is the flow/capacity ratio, and what is the travel speed can be operated at the location? • If the DS is calculated each direction traffic, then please recalculate each DS.

  19. Level of Service Analysis • Generally, Indonesian Highway Capacity Manual (IHCM) is produced by referring to the US HCM. Nevertheless, what is used or applied in the US HCM, it does not apply in the IHCM. This relates to the differences condition between both countries that can be clearly seen in the traffic movement system, and type with composition of vehicles in the field. One of analysis that not used exactly same as the US manual is the analysis of level of service.

  20. IHCM is used degree of saturation and speed of light vehicle as standard vehicle. • Although the classification level of service does not clearly show in the IHCM, but this manual has provided the limits value of degree of saturation. • The example of figures provided by DGoH (1997) can be seen in the next page.

  21. It is found that there are four degree of saturation limit values, i.e. 0.25, 0.5, 0.75, and 1.00. • If these values are used to classify the performance of traffic flow and refers to the explanation of each level in US HCM, then the classification of LOS can be seen in the next table.

  22. Range and Description Each Class of Level of Service (LOS)

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