Trafficware is excited to announce an update to the background image feature for Bing Maps in Synchro 10. Similar updates will be coming to Synchro 9 soon. This feature allows users to download a background image from Bing Maps without exiting Synchro.
Synchro should alert you that the update is available next time you open the software, or you search for it using the 'Check for Updates' button on the Help tab.
Trafficware is excited to announce the upcoming release of Synchro 10, supporting the latest edition of the Highway Capacity Manual (HCM) 6th Edition methodology for signalized and unsignalized intersections, two-way-stop-control intersections, all-way-stop-control intersections, and roundabouts.
Synchro 10's user interface was updated, introducing a new look and feel with easy-to-use ribbon bar controls.
Today we are continuing with the series of posts about calibrating SimTraffic. Travel times are often collected in the field and compared to the SimTraffic arterial report. If needed, speed can be calibrated either with the Link Speed in Synchro or the Speed Factor in SimTraffic.
Adding to our series about SimTraffic calibration, today's post focuses on the Turning Speed. Turning Speed is a simple item to code, but it can make a noticeable difference when modeling intersections with large turning radii or freeway ramps. This setting is a great place to start calibrating your SimTraffic model.
Make sure to read rest of the series; we have discussed Link OD Volumes, Lane Alignment, and the Positioning & Mandatory Distances.
We will be focusing on the westbound right turn of the intersection shown below. As you can see, it is a free-flowing channelized right-turn. With this type of geometry, drivers typically turn right at speeds approximately 5 to 8 mph higher than a typical non-channelized right turn (NCHRP 208).
Today's post is a continues our series on calibrating SimTraffic. Along with the Lane Alignment and Positioning Distances, the Link OD Volumes determine lane utilization in SimTraffic.
Located in the Volume Settings window, the Link OD Volumes window allows control over the origin and destination of two adjacent intersections. Link OD Volumes can be used to reduce or eliminate certain turn combinations, such as preventing vehicles from turning left twice at a freeway or wide median arterial.
Lane Alignment is a simple, but important, calibration parameter for SimTraffic. This setting controls how the approach lane(s) align with the receiving lanes at an intersection, and is particularly important for locations with more receiving lanes than approach lane(s). Edit this setting in Synchro's Simulation Settings window; there are four possible choices:
When modeling a roadway with a large median, it can sometimes be difficult to determine if it should be modeled as one intersection with median or as two separate intersections. Ask yourself this question: 'Do drivers ever stop in the median?' If they do, then it should be modeled as two separate intersections. Let's look at a real life example...
Here you can see two nearby intersections that are geometrically similar, but drivers are treating the median differently.
On the northern intersection, there are vehicles stopped in the median waiting to turn. You may also notice there are stop lines in the median, encouraging this behavior.
In contrast, drivers travel through the southern intersection with a single maneuver. There are no stop lines, and no vehicles stopped in the median.
In order to model this behavior in SimTraffic, the southern intersection should be modeled as one intersection with a median. The northern intersection should be modeled as two separate intersections, that may operate on a single controller using the Cluster Editor.
Applying weighting factors is a great way to customize the optimization routine in Synchro 9. If you haven't tried this new feature yet, this post will get you started. Weighting factors allow you to favor specific movement(s) at some or all of the intersections in the network. There are two choices to apply weighting factors, to specific phase(s) or there is a shortcut to apply a single weighting factor to all of the coordinated phases. Choose which method to use in the Optimize Cycle Lengths window.
One of the best ways to calibrate the lane utilization in SimTraffic is using the Positioning and Mandatory Distances. This post will give you a good idea on when and how to use these settings to calibrate your model.
Traffic flow in SimTraffic is based on a series lane changing and car following algorithms. There are ten different driver types to provide various driver behaviors, including both aggressive and passive drivers. As vehicles are added to the network, they have a pre-determined path and already know several of their upcoming movements. This pre-determined path and the driver type will influence each driver’s lane change behaviors.
The decision on when a vehicle change lanes is based on two key parameters. The first is the Mandatory Distance and is defined as the distance from an intersection that a vehicle must have changed lanes to complete a required movement. If the vehicle has not changed lanes by this point, the vehicle will stop and wait for a gap. The second parameter is the Positioning Distance and is defined as the distance from the location of the Mandatory Distances that a vehicle will attempt to make a lane change to avoid being forced to complete a mandatory lane change. The figure below highlights the relationship of these parameters.
Both of these parameters can be adjusted at the local link or global network level.
The 2010 Highway Capacity Manual (HCM) procedures may be used to analyze coordinated intersections, but there are some unique settings such as the Platoon Ratio required for accurate results. Chapter 18 in HCM 2010 highlights the procedures related to isolated signalized intersections, while Chapter 17 focuses on the procedures associated with coordinated intersections. The Platoon Ratio describes the quality of progression for a platoon of vehicles arriving on green. As described in HCM 2010, the user should select a Platoon Ratio based on field observations and their knowledge of the corridor.
Table 1: Traffic Flow Along Coordinated Arterials