Corridor Planning Guidebook

The questions in this section are intended to prompt input and discussion beyond the technical data considered below. People familiar with the study corridor can provide a depth of understanding that is not always captured in the technical analysis. Response themes or highlights from each should be summarized in the qualitative input section of the existing conditions report.

Agency Engagement

Coordinate with the project team to ask appropriate public agency staff questions such as these. Summarize responses as appropriate.

• Which intersections are known to have recurring delay and/or reliability issues? Which legs have the most queueing?
• Which segments are known to have recurring delay and/or reliability issues? Are there any known or assumed causes? Are the issues occurring at specific times of day or days of the week? Are delay or reliability issues related to weather events (snow, ice, rain, fog)?
• Is there recurring freeway interchange queuing or along entrance or exit ramps?
• Is there typically event-related congestion? How is MnDOT involved in event congestion management?
• If you are someone who travels along this corridor, what concerns you when it comes to critical connections for motor vehicles?
• Are there businesses along the corridor with known challenges related to deliveries or other freight concerns? Does the corridor have an Oversize/Overweight (OSOW) designation?
• Are there any planned or potential developments, particularly of a commercial, industrial, or freight nature, that we should be aware of?
• Do community members let you know about relay and/or reliability or other vehicle mobility concerns along this corridor? If so, where, and what issues are they experiencing?
• Are there any known geometric deficiencies that might affect motor vehicle connections, such as sight distance issues or turn lane lengths?
• Are there any issues today with emergency medical services getting where they need to go efficiently?

Public Engagement

Coordinate with the project team to incorporate questions such as these into public engagement activities. Summarize responses or themes as appropriate.

• Are there intersections or segments that are known to have recurring congestion issues? Can you describe the issues, and if there are particular times of day they occur?
• When you travel along the corridor, are travel times reliable? Or are there recurring days when it takes longer to travel through the corridor than expected?
• Do you ever avoid driving on this part of the road or avoid certain intersections? Why? What times of day?
• Do you ever have trouble getting where you need to go, or have trouble getting there on time when you drive?

The table below shows the technical topic measurements and data to be included in the existing and future conditions analysis for Critical Connections: Motor Vehicles and Freight. See Appendix C: Plan Type Data Matrix for direction on level of detail and items that may be optional based on corridor plan type. The items below also may be modified by the scope of work for an individual corridor plan. With respect to traffic data, this could include cases where the area of influence extends beyond the corridor and a network analysis may be needed.

Table 12. Critical Connections: Motor Vehicles and Freight Topics and Data

Topic	Measurement	Data Source
Volume Counts	Passenger vehicle turning movements, heavy vehicle turning movements, pedestrian and bicycle crossings at corridor intersections	Field counts or platform like StreetLight
Access Management	Compliance with MnDOT’s Access Management Manual	Aerial imagery & MnDOT Guidelines
Roadway Capacity, Travel Delay, and Reliability	Existing Volume-to-Capacity Ratio	AADT (MnDOT’s Traffic Mapping Application) Highway Capacity Manual
	Future Volume-to-Capacity Ratio	AADT (MnDOT’s Traffic Mapping Application) Highway Capacity Manual
	Vehicle Miles Traveled (VMT)	AADT
	Vehicle Travel Delay	ClearGuide (primary source) Other sources if appropriate, per guidance
	Vehicle Travel Time Reliability	ClearGuide (primary source) Other sources if appropriate, per guidance
	Truck Travel Time Reliability Index (TTTRI)	State Freight Plan (Chapter 3)
Transportation Systems Management and Operations (TSMO)	Existing TSMO Strategies and Activities	RTMC (for in-place ITS equipment statewide), staff input, aerial imagery
Freight and Intermodal	Highway Freight Routes and Tonnage	Minnesota Freight webpage maps
	Rail Crossings	Minnesota Rail Viewer Application
	Other Freight and Intermodal Characteristics	Minnesota Freight webpage maps

Data

Collect counts to document passenger vehicle turning movements, heavy vehicle turning movements, pedestrian and bicycle crossings at corridor intersections as outlined in the scope of work (number of intersections to count and length of time will vary by corridor). Volumes are typically collected using video at the intersection at the start of a corridor planning process but may be collected using StreetLight.

Documentation

Document the following:

• Peak periods (how long, time of day, whether there are special events)
• Percent heavy vehicles by time of day
• Volume profile charts by time of day
• Seasonality trends of volumes (some plans)
• Summarize counts using maps and tables, include full turning movement counts should be included as an appendix to the corridor plan.

MnDOT defines Access Management as the planning, design and implementation of land use and transportation strategies in an effort to maintain a safe flow of traffic while accommodating the access needs of adjacent development. For corridor planning purposes, the guidebook focuses on the locations of driveways and intersections, whether access spacing aligns with MnDOT’s Access Management Manual, and potential improvements or access closures to meet guidelines if they are not met under current conditions. Guidebook users may also document any difficult turning maneuvers determined during field evaluation or when obtaining qualitative input, and whether turn lanes are warranted. More information on whether turn lanes are warranted can be found in Chapter 4 of MnDOT’s Traffic Engineering Manual.

Data

Aerial imagery can be used to identify locations of driveways and intersections along the corridor and categorize as appropriate. Information on access types and spacing are included in Chapter 2 and Chapter 3 of MnDOT’s Access Management Manual, which can be found on the Access Management Resources webpage. Land Use Context Categories are also a key data element, collected in Step 2.

Documentation

Using aerial imagery, identify locations of driveways and intersections along the corridor and categorize as appropriate. Summarize corridor access characteristics and alignment with MnDOT guidelines using a map or tables as appropriate.

The sections below outline how to collect data and perform analyses for each Travel Delay and Reliability measurement.

Existing Volume-to-Capacity Ratio

The volume-to-capacity ratio (V/C) is the ratio of the flow rate to the theoretical maximum capacity and as described in this Guidebook is measured using daily volumes and capacities for a higher-level evaluation of the degree of utilization for a corridor. A V/C over 1 indicates a location is over capacity. It should be noted that because this is a high-level analysis, a V/C below 1 does not necessarily indicate that a corridor is under capacity, and may have other operational issues such as weaving, merging, etc., which may be understood through qualitative input from corridor users, or in more complex studies may require more detailed modeling efforts.

Data

The data needed to document the volume-to-capacity ratio includes the following, with instructions included below: 

• Annual Average Daily Traffic (AADT). Obtain the most recent daily vehicle volumes for each segment of the corridor using MnDOT’s Transportation Data Management System. (Note that the same AADT data is also requested in Step 2.)
• Capacity. Determine the capacity of the corridor by segment or intersection using the Highway Capacity Manual, published by the Transportation Research Board (TRB).

Documentation

Summarize corridor V/C using a table (or tables) that documents V/C by segment and/or intersection as applicable.

Future Volume-to-Capacity Ratio

The future V/C ratio estimates future V/C using forecasted volumes.

Data

The data needed to document the volume-to-capacity ratio includes the following, with instructions included below: 

• Forecast AADT. Forecasted volumes can be calculated or obtained using some or all these sources:
  • MnESAL Traffic Forecasting Tool on MnDOT’s Traffic Forecasting webpage
  • Regional travel demand model or other local agency forecasts, if available
  • Coordination with appropriate MnDOT point of contact for the project (usually the district traffic engineer)
  • Coordination with MnDOT’s Section Director for Traffic Forecasting & Analysis (TFA) - contact information available here
• Capacity. Utilize the same capacity identified above. There may be some exceptions to this, such as if the future “no build” condition will include known capacity changes within the corridor outside of what is being studied in this corridor plan.

Documentation

Summarize corridor V/C using a table that documents V/C by segment.

Vehicle Miles Traveled

The existing vehicle miles traveled (VMT) metric will serve as a baseline to understand existing usage and provide information for Step 4.

Data

The data needed to document the volume-to-capacity ratio includes AADT (described above) and corridor length, which should be known at this point in the evaluation. Multiplying the AADT and corridor length in miles will provide a VMT.

• Traffic Volumes. See above for obtaining AADT and use only values where the AADT Code is from an actual seasonally adjusted count (see the superscript code in the application).
• Segment Lengths. For each AADT segment, document the length. If only a portion of the AADT segment is included in the corridor, document that portion.

The equations below describe how to calculate VMT using AADT and segment lengths. To convert AADT by segment to VMT, use Equation 1. Use Equation 2 to calculate total VMT that is the sum of all segments.

• Equation 1: VMT for Segment X

VMTx=AADT(SL*PL)

Where:
AADT = AADT of segment
SL = Segment length used for traffic forecast
PL = Portion of length of segment within the corridor bounds (i.e., if a SL is fully encompassed within the corridor the value = 1; if only a portion of the SL is within the corridor bounds, then the project value will be between 0-1 representing the portion of the project length from the point of the last segment to the end of the project limits)

• Equation 2: Corridor VMT

VMT corridor=VMTa+VMTb+VMTd+VMTc+...

Where:
VMTX = Average Daily VMT output from each segment, with different sub-letters for each corresponding segment
VMTcorridor= Total Average Daily VMT forecasted in the affected area

Documentation

Create a table documenting corridor VMT.

​Corridor Segment Number	​TFA Location ID	​Segment Length (miles)	​Current Average Annual Daily Traffic (AADT)
​1	​	​	​
​2	​	​	​
​3	​	​	​
​4	​	​	​

Vehicle Travel Delay

According to MnDOT’s Traffic Engineering Manual (TEM), delay is defined as an interruption of normal travel involving a slowing or stopping. It is the difference between interrupted and uninterrupted travel times.

Data

ClearGuide, a traffic analysis tool developed by Iteris, is recommended as the primary, or initial, method for assessing vehicle travel delay in a corridor. ClearGuide allows MnDOT staff and consultants to access, analyze, and interpret traffic performance data across the state. MnDOT staff and consultants interested in using ClearGuide can request access through their MnDOT point of contact or apply online; access to ClearGuide requires MnDOT authorization. ClearGuide is only available for use on projects involving MnDOT roadways.

If there are more detailed traffic analysis needs, such as if the corridor study will contribute to an Intersection Control Evaluation (ICE) or other reasons mentioned in the table above, analysts can utilize other software, but guidance for that level of detail is not included here. Refer to the TEM linked above for more information on more detailed analysis methods and resources, such as Highway Capacity Model (HCM) and Highway Capacity Software (HCS), Synchro/SimTraffic, or Vissim, if determined to be appropriate for the corridor plan.

ClearGuide can be accessed at this link: https://mndot.iteris-clearguide.com/. Users not familiar with ClearGuide may need additional guidance for using this tool. Contact MnDOT’s RTMC for assistance, training, or more information.

Documentation

Summarize vehicle delay using tables, graphs, maps, or narratives as appropriate. Identify areas of concern.

Vehicle Travel Time Reliability

Similar to the Vehicle Travel Delay measurement above, the guidebook focuses on a high-level analysis of existing conditions using ClearGuide. If there are more detailed traffic analysis needs, refer to the TEM linked above for more information on other analysis methods and resources, such as HCS, Synchro/SimTraffic, or Vissim.

Data

Obtain vehicle travel time reliability information using ClearGuide (detail above).

Documentation

Summarize vehicle delay using tables, graphs, maps, or narratives as appropriate. Identify areas of concern.

Truck Travel Time Reliability

MnDOT routinely collects truck data using in-ground sensors and other tools. That data is used to calculate reliability through a Truck Travel Time Reliability Index (TTTRI), which is a federally defined measure calculated by the ratio between the 95th percentile travel times (slow vehicles) and 50th percentile (average truck travel times). A higher TTTRI represents conditions where truck travel time reliability is a concern.

Data

MnDOT publishes a Freight Bottleneck Report that includes a statewide map identifying the TTTRI for state highways. The report is updated every two years; use the most recent version available.

Documentation

Document the TTTRI for the corridor using the published map or table.

TSMO focuses on improved highway operations by improving safety, efficiency, and reliability through the use of technology or improved operational procedures. Examples of TSMO strategies include the following:

• Traffic Management Systems
• Traffic signal timing and coordination
• Transit advantages
• Special event management
• Managed lanes
• Road weather management

Data

Information from in-place ITS devised state-wide is available from MnDOT’s RTMC. Aerial imagery also may show TSMO related infrastructure, such as ramp meters, dynamic signage, cameras at signals, and high-occupancy vehicle lanes. Information on other TSMO strategies or activities should be gathered from MnDOT and local agency staff. MnDOT’s TSMO webpage will have the latest TSMO resources and contact information.

Documentation

Using aerial imagery, input from the MnDOT project team, identify any TSMO strategies or activities in use on the corridor. Existing TSMO strategies and infrastructure can typically be described using a narrative. If there are multiple tools in use along a corridor, or they are implemented at key locations but not others, a map may provide more complete documentation.

The sections below outline how to collect data and perform analyses for each freight and intermodal measurement.

Highway Freight Routes and Tonnage

According to the Minnesota State Freight Plan, nearly two thirds of all freight moved in the state is carried by truck. Trucks play a crucial role in connecting shippers with other transportation modes.

Data

Freight-related maps are available on the “Maps & Data” tab of MnDOT's Freight Webpage. Relevant maps for this topic include the following:

• Oversize/Overweight Superload Corridors
• Twin Trailer Network
• Truck Freight Tonnage
• Weigh Stations in Minnesota

Documentation

Identify any freight-related characteristics of the corridor, as described in the resources above, using a map or table. Relevant information includes inclusion of the corridor in Minnesota Twin Trailer Network, allowed tonnage, and restrictions related to height, width, or safety on Oversize/Overweight (OSOW) Superload Corridors. Also note if truck parking and weigh station facilities are present in the corridor.

Rail Crossings

At-grade rail crossings may impact a highway corridor either directly (the railroad crosses the highway at grade) or indirectly (the railroad crosses an intersecting roadway at grade in proximity to the highway and causes backups on the highway). It is important to understand these characteristics as they can impact safety and mobility along the corridor. Coordinate with the designated MnDOT Railroad Project Manager for the region if any work is planned along railroad corridors or near railroad at-grade crossings. Contacts for the railroad project management staff is available here.

Data

Information on public rail crossings in the state can be accessed using the Minnesota Rail Viewer Application. More detailed information is available as the map is zoomed in. If there are rail crossings present along the corridor, the crossing type icon can be clicked to access information for documentation.

Documentation

Document the following information in narrative, table, or map format:

• Date that you contacted the Railroad Project Manager assigned to your region
• Rail crossing location(s) and type(s)
• Rail route network name
• Information from the USDOT Crossing Inventory Form (including, but not limited to, estimated train movement counts, type and count of tracks, speed of train at crossing, detection and signals, control devices, signs, activated warning devices, illumination, and crossing angle)
• Summary of any incidents included in a USDOT Accident/Incident Report
• Description of characteristics based on aerial imagery or visual references linked in mapping application

Other Freight and Intermodal Characteristics

This measure can capture any additional characteristics for the corridor related to freight and intermodal features such as rail, airport or other transfer stations and ports and waterways, including freight generators, intermodal connectors, intermodal yards, airports, port facilities, and warehouses. (Airports are described in more detail as a subtopic in Section 3.7 Critical Connections: Other Topics.) Intermodal Freight Terminals can be identified using the Intermodal Terminals in Minnesota map on the “Maps & Data” tab of MnDOT's Freight Webpage. If there are truck-rail container intermodal facilities, seaport facilities, airport facilities on or near the corridor, or if the corridor is a key connection to any of these facilities, document them here. Any other relevant freight characteristics such as nearby truck stops or other hubs for freight traffic and parking can be documented here.

This section identifies topics that are typically relevant only to select corridors or locations. They should be considered and included if determined to be relevant by the project team.

Job Accessibility

Topic	Measurement	Potential Data Sources/Resources
Job Accessibility by Car	Number of jobs accessible within 30 minutes of driving	MnDOT Performance Dashboard: Average Jobs Accessible Within a 30 Minute Drive

 

Origin-Destination Data

An origin-destination analysis may be conducted using StreetLight for some studies, to determine route patterns, and understand volume trends over time. This analysis also may be done qualitatively by identifying major origins and destinations on a map.  

Vehicle Gap Analysis

An analysis of gaps between vehicles (or vehicle platoons) may be conducted to determine gap length and availability. This may be considered if there are known gap issues or if it comes up during qualitative input.

Multiple strategies may be used in an analysis of motor vehicles and freight aimed at fostering healthy and vibrant places that reduce disparities and promote healthy outcomes for people, the environment, and the economy. Guidebook users should prepare a summary of how healthy equitable communities were considered and include it in the memorandum or report that documents the motor vehicles and freight assessment.

Healthy Equitable Communities

Use a combination of demographic information (Step 2), technical input and input from community members and agency staff to provide responses or observations related to the questions below.

• Are there critical connections issues that prevent roadway users from shifting from motorized to non-motorized modes? Is congestion presenting air quality concerns in the corridor?
• Are there critical connections issues that make it challenging for people to get to jobs? For delivery vehicles to access businesses along the corridor, or any other issues that affect the movement of goods?
• Are freight movements creating issues that negatively impact any communities adjacent to or near the corridor?
• If traffic modeling was completed using Synchro or similar software, what level of fuel consumption and emissions does the corridor have?