CHAPTER 10URBAN STREET CONCEPTSCONT

CHAPTER 10
URBAN STREET CONCEPTS
CONTENTS
I. INTRODUCTION ............................................................................................10-1
II. URBAN STREETS .........................................................................................10-1
Flow Characteristics .........................................................................................10-3
Free-Flow Speed ..............................................................................................10-3
Running Speed ................................................................................................10-3
Travel Speed ....................................................................................................10-4
Time-Space Trajectory ......................................................................................10-4
Levels of Service ..............................................................................................10-4
Required Input Data and Estimated Values .....................................................10-5
Urban Street Class ...........................................................................................10-5
Length ..............................................................................................................10-7
Free-Flow Speed ..............................................................................................10-7
Signal Density ..................................................................................................10-8
Peak-Hour Factor .............................................................................................10-8
Length of Analysis Period ................................................................................10-8
Service Volume Table ......................................................................................10-9
III. SIGNALIZED INTERSECTIONS .................................................................10-9
Signalized Intersection Flow Characteristics ....................................................10-9
Traffic Signal Characteristics ..........................................................................10-14
Saturation Flow Rate ......................................................................................10-15
Signalized Intersection Capacity ....................................................................10-15
Level of Service ..............................................................................................10-15
Required Input Data and Estimated Values ...................................................10-17
Lane Additions and Drops at Intersections .....................................................10-17
Exclusive Turn Lanes .....................................................................................10-17
Exclusive Left-Turn Lanes .............................................................................10-18
Exclusive Right-Turn Lanes ...........................................................................10-18
Number of Lanes ............................................................................................10-18
Other Features ...............................................................................................10-18
Intersection Turning Movements ....................................................................10-19
Default Values in Absence of Turning Movement Data .................................10-19
Turning Movement Estimation .......................................................................10-19
Peak-Hour Factor ...........................................................................................10-21
Length of Analysis Period ..............................................................................10-21
Intersection Control Type ..............................................................................10-21
Cycle Length .................................................................................................10-21
Lost Time and Estimation of Signal Phasing .................................................10-22
Effective Green Ratio ...................................................................................10-23
Arrival Type ...................................................................................................10-23
Progression Adjustment Factor ....................................................................10-23
Incremental Delay Adjustment ......................................................................10-24
Upstream Filtering/Metering Adjustment Factor ...........................................10-24
Base Saturation Flow Rate ..........................................................................10-24
Adjusted Saturation Flow Rates ..................................................................10-24
Lane Widths ................................................................................................10-24
Heavy Vehicles ............................................................................................10-25
Grades .........................................................................................................10-25