1. CE 578 Highway Traffic Operations Introduction to Freeway Facilities Analysis

2. Objectives Process of freeway facility analysis Limitations of methodology

3. Bringing it All Together A freeway facility is comprised of different sections Each section is broken down into one or more segments and the steps to do this are: Use the HCM methodologies

4. Bringing it All Together

5. Flow of Methodology

6. Time-Space Domain

7. Demand volume (d) (veh/hr) Capacity (c) (veh/hr) d/c ratio estimated speeds (S) estimated densities (D) LOS

8. Adjust Demand Input (observed or estimated) –Traffic counts at entrances –Traffic counts at exits Entrance volumes current demand volumes (O i ) Exit counts and demand volumes (E j and D j ) Estimate exit demands Segment demand

9. Limitations Maximum length (9 to 12 miles) Flexible analysis period but 15 minute time intervals Vehicles leaving before or after the analysis period Complex occurrence of interactive bottlenecks Must adjust demands to consider effects of demand responsive –Rerouting –Mode choice –Demand management

10. Limitations (cont.) Only local oversaturated flow First and last segments must be unsaturated for the duration of the analysis period All segments must be unsaturated at the beginning and ending time intervals of the analysis period Procedure not intended to implemented manually For heavy congestion may want to implement a simulation methodology