Work Zone - 3.03 Mobility Analysis Tools
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3.03 Mobility Analysis Tools
Understanding the anticipated type and extent of work zone impacts, aids the development of effective TMPs. Analysis may necessitate the use of software tools depending on the degree of analysis required. Some tools were designed for work zone analysis while other traffic analysis tools, not specifically designed for work zones, can also be useful for analyzing work zone situations. This section discusses various tools available to perform the analyses required to develop and implement TMPs. Contact the [https://www.michigan.gov/mdot/Business/work-zone-mobility WZMU; for assistance with items in this section or if utilizing tools not included herein.
3.03.01 Construction, Congestion, Cost (CO3)
(Updated 1/20/2020)
CO3 is a spreadsheet/software tool that estimates the magnitude and impacts of traffic congestion, including cost impacts on road users that can be expected during a construction project. CO3 measures congestion variables such as delay, diverted vehicles, and backup. In addition, a user can estimate and document project costs for alternative methods of maintaining traffic. The program allows for quantification of decreases to demand, such as diversions to alternate or detour routes. MDOT provides additional information regarding the CO3 software including the most recent spreadsheets, user manual, and updated user cost inputs. These resources are available on the MDOT website: CO3 Spreadsheets and User Manual.
CO3 is used in Michigan to estimate delay and user cost for work zones on uninterrupted flow facilities and traffic regulator operations. The program requires hourly traffic data inputs throughout the day which should be readily available at TDMS. The program allows the work zone capacity to be inputted for each hour of the day. An example summary view of the spreadsheet output is located in the Appendix B: Mobility Analysis Tools.
A. Important Notes Regarding CO3 Inputs
- The “method travel distance” and “normal travel distance” are usually the same for a work zone which is open part width or with a route around (i.e. crossovers on a freeway). The only exception to this rule, is a full closure.
- Inputs for “diversion” should be considered in context of a voluntary alternate route. The analyst should seek input from MDOT BTP, Region or TSC to determine an appropriate diversion rate.
- The “normal travel speed” should be the existing posted speed limit. Speed delay calculations are always made in comparison to this number.
- The speed delay threshold and range values should be entered for work zones that operate with a reduced speed limit at all times, and a lower speed limit during active work periods (i.e. 45 mph where workers present and 60 mph at all other times).
- If only speed delay threshold values are filled in, then any time period with a capacity above this threshold will operate at the normal travel speed (i.e. 60 mph during working periods and 70 mph at all other times).
- The speed when D~0, and speed, when D=C, values should be determined using the CO³ Common Inputs sheet.
- The adjusted capacity must be calculated using the method described in Section 3.01.01 A.
- For work zones with hourly lane closure restrictions, the capacity may be modified to accurately reflect the capacity for each time period.
- For training needs and additional questions please contact the WZMU.
- The MDOT website for C03 has a number of resources that provides additional information and details on the required inputs.
3.03.02 Synchro and SIM Traffic
Synchro and SIM Traffic programs are frequently utilized by MDOT for signal timing and geometric design evaluations. Many validated network models exist and may be utilized for work zone evaluation. Outputs include travel times, levels of service, and other measures of effectiveness.
3.03.03 Synchro
Synchro is a macroscopic capacity analysis and optimization model which performs a straight-forward analytical capacity analysis allowing users to get a measure of delays, queues, etc. based on equations.
Synchro also optimizes signals in a network and uses the intersection capacity utilization method to determine capacity for signalized and un-signalized intersections. It supports the HCM methodology and is recommended for determining the travel time on interrupted flow facilities.
A. Important Notes when using Synchro for Signalized Work Zones
- Between the existing scenario and the temporary configuration, the geometry must be updated to reflect the available lanes.
- Any adjustments to traffic volumes or signal phasing and timing should be documented and applied where appropriate.
- The Link Speed input should be set to represent the work zone posted speed limit. Synchro uses Link Distance and Link Speed to determine the Running Time.
- The Arterial LOS report can be used to summarize travel time for a work zone treated as an arterial street. The LOS analysis provides a high level analysis and maybe used for planning and scoping purposes. Several dummy nodes must be added to the network to represent the boundaries of the work zone, since running time is only reported between signalized intersections. The dummy nodes can be coded for 100% green time which represent the entrance and exit for the work zone.
- The summation of running time and signal (control) delay results in the Travel Time. This value should be compared with the existing scenario to determine the travel time increase predicted for the work zone.
3.03.04 SIMTraffic
SIMTraffic is a microscopic simulation model that simulates signalized and un-signalized intersections (including roundabouts) and the interaction that occurs between intersections.
A. Important Notes when using SIMTraffic for Signalized Work Zones
- The results of the SIMTraffic Arterial LOS report may differ from those presented in the Synchro report.
- The SIMTraffic analysis includes several parameters that should be adjusted to simulate the intersections.
- This microscopic Arterial LOS is recommended for significant and potential significant projects to identify operational issues.
- Information for calibrating the SIMTraffic model is provided in MDOT’s Electronic Traffic Control Device Guidelines.
3.03.05 Highway Capacity Manual (HCM) and Highway Capacity Software (HCS)
The Highway Capacity Manual (HCM) is a reference document that contains concepts, guidelines, and computational procedures for computing the capacity and LOS on various facility types. The HCM can be used for both planning and operational analyses. A planning analysis gives measures of effectiveness such as time delay, average travel speed, LOS and V/C ratios. An operational analysis allows for diagnosing, testing, and designing mitigation measures.
Highway Capacity Software (HCS 2010) is a package of modules to implement the HCM procedures to compute capacity for various facility elements such as intersections, segments, and ramps. The software is macroscopic in scope and provides outputs with limited data input.
This software is used in Michigan to evaluate capacity situations for independent facility elements such as an entrance ramp merge point, or a stand-alone intersection. For traffic signal evaluation, Synchro is recommended.
3.03.06 PTV-VISSIM (Planung Transport Verkehr) Vissim (Verkehr In Städten – SIMulationsmodell)
PTV-VISSIM is a microscopic, time-step and behavior based simulation model developed to analyze roadways and transit operations. VISSIM simulates urban and highway traffic including pedestrians, bicyclists, and motorized vehicles. VISSIM can model integrated roadway networks found in a typical corridor as well as various modes consisting of general-purpose traffic, buses, HOV lanes, high occupancy toll lanes, rail, trucks, pedestrians, and bicyclists. Changeable message signs, ramp metering, incident diversion, transit signal priority, lane control signals, and dynamic lane control signs can also be modeled with VISSIM.
Note: VISSIM is data intensive and requires special expertise. It should be limited to situations in urbanized areas where impacted roadways are typically at capacity. The model requires graphical coding of a network and calibration variables. Additional information regarding this program and variables can be obtained from the MDOT Congestion and Mobility Unit.
3.03.07 Travel Demand Models and Tools
A. TransCAD
TransCAD is a Geographic Information System (GIS) based software tool used to implement travel demand modeling. Using the four-step transportation modeling process and TransCAD software, travel demand models are used to identify existing and future highway capacity deficiencies and analyze potential improvements. Travel demand modeling refers to the development of a series of mathematical relationships, specifically designed to simulate existing and forecasted travel patterns.
Travel demand models have been developed for large urban areas in Michigan for the governing MPO. A statewide model has also been developed to evaluate alternatives outside of urban area boundaries. Travel demand models replicate existing traffic, the effects of impedance to that traffic, and where and when future congestion will occur. They can also estimate the impact of congestion in terms of changes in the LOS or the amount of delay saved from future transportation improvements. This allows a comparison of the benefits of various transportation projects.
In complex situations or for high impact projects, these models should be used to evaluate the diversion of traffic from work zones due to lane closures or other impedances as well as identify routes that will be impacted by the work zone. The output from the travel demand model can be used to justify diversion rates used for alternate routes.
B. DynaSmart-P
DynaSmart-P is a dynamic traffic assignment analysis tool that may be used for regional work zone management. This program combines dynamic network assignment models used primarily with demand forecasting procedures for planning applications, and traffic simulation models and are, used mainly for traffic operations studies.
Potential applications include; assessing the impacts of alternate traffic control strategies for work zones, incidents, and special event management, and assessing the impacts of ITS technologies on the transportation networks. In addition, DynaSmart-P can evaluate congestion-pricing schemes for toll roads and produce traffic operations data for air quality analyses.
C. Regional Integrated Transportation Information Systems (RITIS)
RITIS is a tool used to compile, analyze, and archive speed and travel time data. RITIS includes many performance measures, dashboards, and visual analytics tools that help agencies gain real-time situational awareness, measure performance, and communicate information between agencies and the public.
RITIS utilizes real-time data feeds and automatically compiles and standardizes data obtained from multiple agencies to provide an enhanced overall view of the transportation network. Users can filter information specific to their project, road, or regional area. The RITIS tools allow users to identify incident hot-spots, analyze queue lengths and traffic congestion/bottlenecks, monitor speed and delays caused by incidents, work zones, weather, events, and other causes, and evaluates the effectiveness of transportation operations strategies. Agencies are able to view transportation and related emergency management information and use it to improve operations and emergency preparedness.
Data within RITIS is archived and may be downloaded exported to perform independent analyses. MDOT uses RITIS for before and after analysis of construction projects to aid in determining the effectiveness of the project on traffic operations. RITIS may also be used to provide information to third parties, the media, and other traveler information resources. Information about the tools within RITIS is available at: https://www.ritis.org/tools
Access to RITIS may be requested through the MDOT Project Manager. MDOT employees may gain access at no cost by visiting https://www.ritis.org/register/. A login ID is NOT needed to view reports generated within RITIS.
