Topic 6 Delay and Offset

1. Topic 6 DelayandOffset

2. Delay • Delay: the most commonly used performance measure • Types of Intersection Delays • Stopped delay • Total delay (control delay) • Time in queue delay

3. Delay Studies Distance Total Delay (Control Delay) Stopped Delay Stop Line Deceleration Acceleration Time

4. Time in Queue Delay Distance Stopped Delay Stop Line Time in Queue Delay Time

5. The HCM Delay Equation Uniform Delay

6. Uniform Delay Cumulative Arrival V S r g0 Cumulative Departure g C

7. Uniform Delay V Cumulative Arrival S S C Cumulative Departure C

8. Random and Over-saturation Delay V S Cumulative Arrival S C Cumulative Departure C

9. Delay with Initial Queue V S Cumulative Arrival S C Cumulative Departure C

10. Uniform Delay with Platoon Arrival(Platoon on Red) N Vnp Cumulative Arrival Vp S r g Cumulative Departure C

11. Uniform Delay with Platoon Arrival(Platoon on Green) N Vp Cumulative Arrival Vnp S r g Cumulative Departure C

12. Example Assume a two-lane one-way street links two intersections i and j, which is 800 feet apart. The one-way link flow is all through traffic and has a volume of 1000 vph. Saturation flow rate is all 1800 vphpl. Assume vehicle travel speed is 25 mph. The system cycle is 70 sec, and the effective arterial through greens for the upstream (i) and downstream (j) intersections are 35 sec and 30 sec, respectively. The offsets are 0 and 20 sec for the two intersections, referencing to the start of green of the arterial phases (i.e., arterial phase green at j starts 20 sec later after i). Calculate the uniform delay at intersection j considering (1) no platoon dispersion; (2) with platoon dispersion (α=0.35, β=0.80); (3) What if the offset is 40 sec?

13. No Platoon Dispersion s Flow Rate v t0 ru Time gu C s T.T θ v Time rd gd C

14. Offset - 20 Delay = 3.7 sec/veh

15. Offset - 40 Delay = 13.6 sec/veh