CEE 764 – Fall 2010 Topic 6 Delay and Offset Delay and Offset

CEE 764 – Fall 2010 Delay  Delay: the most commonly used performance measure  Types of Intersection Delays Stopped delay Stopped delay Total delay (control delay) Total delay (control delay) Time in queue delay Time in queue delay

CEE 764 – Fall 2010 Delay Studies Stopped Delay Total Delay (Control Delay) DecelerationAcceleration Stop Line Time Distance

CEE 764 – Fall 2010 Time in Queue Delay Stopped Delay Time in Queue Delay Stop Line Time Distance

CEE 764 – Fall 2010 The HCM Delay Equation Uniform Delay

CEE 764 – Fall 2010 Uniform Delay Cumulative Departure r Cumulative Arrival g g0g0 V S C

CEE 764 – Fall 2010 Uniform Delay Cumulative Departure C Cumulative Arrival V S C S

CEE 764 – Fall 2010 Random and Over-saturation Delay Cumulative Departure C Cumulative Arrival V S C S

CEE 764 – Fall 2010 Delay with Initial Queue Cumulative Departure C Cumulative Arrival V S C S

CEE 764 – Fall 2010 Uniform Delay with Platoon Arrival (Platoon on Red) Cumulative Departure r Cumulative Arrival g V np S C VpVp N

CEE 764 – Fall 2010 Uniform Delay with Platoon Arrival (Platoon on Green) Cumulative Departure r Cumulative Arrival g V np S C VpVp N

CEE 764 – Fall 2010 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?

CEE 764 – Fall 2010 No Platoon Dispersion Time t0t0 Flow Rate gugu C s v ruru Time gdgd C s v rdrd T.T θ

CEE 764 – Fall 2010 Offset - 20 Delay = 3.7 sec/veh

CEE 764 – Fall 2010 Offset - 40 Delay = 13.6 sec/veh