Measuring and Predicting Urban Street Operation

Section A. Pedestrian Delay

NCHRP Project 17-87: Enhancing Pedestrian Volume Estimation and Developing HCM Pedestrian Methodologies for Safe and Sustainable Communities.  One objective of this research was to recommend enhancements to the Highway Capacity Manual (HCM) 6th Edition methods for evaluating pedestrian level of service. The research undertaken to develop these enhancements were documented in the following three working papers.

• Working Paper 1 - Revised Model for Predicting Pedestrian Delay at Uncontrolled Crossings.  This working paper describes proposed revisions to the pedestrian delay prediction methodology in Chapter 20 of the HCM 6th. This methodology is used to predict pedestrian delay at two-way stop-controlled intersections and midblock crossings.  PAPER

• Working Paper 2 - Revised Model for Predicting the Influence of Mid-Segment Crossing Difficulty on Pedestrian Level of Service. This working paper describes proposed revisions to the pedestrian level of service (LOS) prediction methodology in Chapter 18 of the HCM. This methodology is used to predict pedestrian LOS for travel along and across an urban street segment.  PAPER

• Working Paper 3 - Model for Predicting the Pedestrian Delay at Signalized Intersections. This paper describes the development of a methodology for predicting the delay to pedestrians that cross one or more legs of a signalized intersection, where the crossing occurs during two signal phases.  PAPER

Section B. Vehicle Speed and Travel Time on Urban Streets

NCHRP Project 03-115: Production of a Major Update to the Highway Capacity Manual 2010. The objective of this project was to produce the HCM 6th Edition. This project developed updated content for the Urban Streets Methodology. This development is documented in the computational engine and three working papers listed below.

• Computational Engine. Project 03-115 produced an Excel-spreadsheet-based computational engine that automates the urban street facilities, urban street segments, and signalized intersections methodologies. SPREADSHEET

• Note: A 2022 security change by Microsoft prevents Excel files with macros (i.e., with the .xlsm extension) from running unless the analyst changes the file properties to unblock the file macros. Right-click on the filename, select Properties, select General, in the Security section (at the bottom) check the "Unblock" checkbox, and select OK.

The current version of the engine is 8.30 (updated March 2022). This paper documents the changes made for 8.30. PAPER

• Working Paper 10a - Evaluation of the Free‐Flow Speed Prediction Procedure in Chapter 17 of Highway Capacity Manual 2010. This paper describes the findings and recommendations from an evaluation of the free-flow speed prediction procedure described in Chapter 17 of the 2010 HCM. The motivation for this evaluation stemmed from the results of two research projects that identified some limitations of the speed prediction procedure. The paper describes the development of recommended changes to the procedure. These changes were subsequently incorporated in the Highway Capacity Manual, 6th Edition.  PAPER

• Working Paper 3 - Comparison of Urban Streets Methodologies in HCM 2000 and HCM 2010. This paper describes the findings from an examination of the urban streets methodology in Chapter 17 of the Highway Capacity Manual 2010. The objective of the research described in this paper was to determine if the predicted travel speed and level of service for common urban street facilities tend to be different among the two methodologies. The motivation for this evaluation stemmed from the result of a research project that suggested that the changes made to the methodology in HCM 2010 had systematically lowered the predicted level of service for a given street segment, relative to the level of service obtained using the methodology in HCM 2000.  PAPER

• Working Paper 1 - Free-Flow Speed Prediction for Urban Streets. The objective of this paper is to discuss issues related to the development of a free-flow speed prediction model. The development process is focused on the development of a model that explains the effect of various independent variables (e.g., driveway density) on the dependent variable (i.e., free-flow speed). Discussed are the pitfalls of developing a model using only statistics that assess overall predictive fit. The paper discusses the reasons why models that suggest free-flow speed can be estimated as equal to the speed limit + constant (e.g., 5 mph) are unlikely to provide a sound basis for agency infrastructure investment decisions.  PAPER

NCHRP Project 03-107: Work Zone Capacity Methods for the Highway Capacity Manual.   The objective of this project was to develop improved material on the capacity of work zones. Much of this material was subsequently incorporated in the HCM 6th Edition. All of the material is documented in the project final report. The material that addressed urban streets can be downloaded using the following link. REPORT

NCHRP Project 3-79 (Objective A):  Measuring the Performance of Automobile Traffic on Urban Streets.  J. Bonneson, A. Sharma, and D. Bullock.  The objective of this research was to develop techniques to measure the performance of automobile traffic on urban streets for a range of real-time applications, such as: real-time signal control, incident management, and traveler information. Three techniques were developed for measuring queue length and delay for the through movement at a signalized intersection.  One technique was developed for measuring segment running time. The algorithm associated with each technique is described and an implementation guide is provided to facilitate technique implementation.  REPORT

NCHRP Project 3-79 (Objective B):  Predicting the Performance of Automobile Traffic on Urban Streets.   J. Bonneson, M. Pratt, and M. Vandehey. The objective of this research was to revise the methodology in Chapter 15 of the Highway Capacity Manual (HCM) such that it can be used to more accurately predict the performance of automobile traffic on urban streets.  The proposed methodology was described in the form of recommended content for the next edition of the HCM.  REPORT 

• Working Paper No. B-9.3 - Urban Street Performance Prediction: Arrival Flow Profile Prediction  PAPER

SHRP 2 L08: Incorporation of Non-recurrent Congestion Factors into the Highway Capacity Manual Methods. The objective of this project is to determine how data and information on the impacts of the differing causes of non-recurrent congestion on highway capacity can be incorporated into the performance measure and level of service estimation procedures contained in the HCM. This project developed a procedure for predicting urban street travel time reliability that is incorporated into Chapter 17 of the HCM 6th edition.  PROCEDURE

Section C. Vehicle Operations at Signalized Intersections

NCHRP Project 03-29: Production of the Year 2010 Highway Capacity Manual. The objective of this research is to develop an up-to-date HCM that is directly relevant to the facility planning and design needs of engineers and planners in 2010. As part of this project, supplemental research was undertaken to fill knowledge gaps in the HCM 2000. A portion of this research focused on gaps associated with the Signalized Intersections methodology. The findings and recommendations from this research is documented in the following working papers:

• Working Paper No. 6.2 - Signalized Intersections: Procedure for Estimating Fully-Actuated Phase Duration  PAPER

• Working Paper No. 6.3 - Signalized Intersections: Procedure for Estimating Delay  PAPER

• Working Paper No. 6.4 - Signalized Intersections: Procedure for Estimating Back of Queue  PAPER

• Working Paper No. 6.5 - Signalized Intersections: Verification of Methodology  PAPER

FDOT Report D02319: Guidelines for Quantifying the Influence of Area Type and Other Factors on Saturation Flow Rate. J. Bonneson, B. Nevers, J. Zegeer, T. Nguyen, and T. Fong. Saturation flow adjustment factors reflecting the effect of population, traffic pressure, number of lanes, and speed limit were developed for this research. A procedure for using these adjustment factors was also developed. This procedure is intended to be used with the HCM or FDOT’s Quality/Level of Service Handbook to estimate the saturation flow rate for an intersection.  REPORT

Section D. Urban Street Access 

NCHRP Report 395: Capacity and Operational Effects of Midblock Left-Turn Lanes. J. Bonneson and P. McCoy. The objective of this research project was to develop a methodology for evaluating alternative midblock left-turn treatments on urban and suburban arterial streets. This methodology is applicable to three commonly found midblock left-turn treatments: the raised-curb median, the flush median with two-way left-turn lane (TWLTL) delineation, and the undivided cross section. The methodology can be used to evaluate the operational effects, safety effects, and the access impacts associated with a specific midblock left-turn treatment. The operations and safety models were used to develop midblock left-turn treatment selection guidelines based on a benefit-cost analysis approach.  REPORT