CEEn 662
Lab #4
Using Synchro and SimTraffic
For simulating freeway and ramp junctions
According to Trafficware, SimTraffic does not simulate ramp metering (See page 23-1 of the Synchro Studio 9 User Guide, which states “SimTraffic will not model ramp metering, bus stops, bus routes, bus and carpool lanes, light rail, on-street parking, and short-term events.”). Hence, we later use CORSIM (TSIS) in this class to simulate freeways with ramp metering. This lab’s goal is for you to get used to freeway simulation using Synchro Studio. We try to model a ramp areathat does not have ramp metering.
We create a freeway section with two onramps as shown in page 232 of May’s book, 8.2.1 Base Conditions using Synchro Studio to get a feel of freeway simulation. I would like you to see queue forming on a freeway segment that has a demand greater than the capacity of the facility—something like the one you see in Figure 8.8 on page 236. Note that the analysis done in Chapter 8 is a static analysis; hence, what you see in the simulation may be quite different from this one. Pay attention where you see queues. Create a network shown in Figure 8.4 (b) using Synchro. First, use the demand values for time slice 1 in Figure 8.4(b) then the demand values for time slice 2.
Today we will simply use one-interval simulation; so you need to simulate time slice 1 first, then change the demand values, and simulate time slice 2.To do multi-time period analysis, you need to create a UTDF (Universal Traffic Data Format) fileoutsideSynchro Studio for each extra interval you need. CORSIM allows you to create a multi-period analysis file within CORSIM and do a multi-period by simply selecting a multi-period analysis. In that sense, CORSIM is superior to SimTrafficbut the SimTraffic’s output presentation is much better than CORSIM. Synchro is the main tool of this software(signal optimization) and SimTraffic is to give the user a simple simulation analysis and animation that will help the user review the correctness of his or her input data and prepare a 3D animation for clients to understand what may happen with the cases you have analyzed.
Read pages 5-9 and 5-10 of the Synchro Studio 9 User Guide to learn how to make freeway links. First, follow exactly what the instructions on pages 5-9 and 5-10 to learn how to use “bend node” to create the acceleration lane. SimTraffic gather MOE statistics on bend nodes also; make sure you click the Bendnode statistics in the Select Report(s) window after selecting the Create report option (Beware that Synchro does not analyze bend nodes because they are not intersections.). Read a paragraph about the Headway Factor (Also, use the Find command to search through the Synchro Studio 9 User Guide for the Headway Factor). Sample screenshots of Synchro and SimTraffic models are presented in the pagesbelow.
This exercise will help you understand the concept presented in Chapter 8 of May’s textbook later on.
Report of Lab #4: Summarize MOE’s of each freeway link for time slice 1 and 2 from SimTraffic and comment (Make sure you make five15-min runs of each case. Usually making 10 runs is recommended but 10 runs will quickly fill up your account).Show means and standard deviations of the MOEs you chose. Maximum three single-spaced pages. Tables and figures are part of this page limit.
Sample of Time Slice 1
Sample of Time Slice 2