HCM 2010

SIDRA INTERSECTION software complements Highway Capacity Manual (HCM 2010) as an advanced intersection analysis tool. Using SIDRA INTERSECTION, you can evaluate alternative treatments involving signalized intersections, roundabouts, two-way stop and give-way (yield) sign-control, all-way stop sign control, single-point urban interchanges, signalized midblock crossings for pedestrians, all in one package. Intersections with up to 8 legs, each as a two-way road, one-way approach or one-way exit. The Highway Capacity Manual version of SIDRA INTERSECTION offers options for US Customary and Metric units.

The Highway Capacity Manual is prepared by the Transportation Research Board (TRB) Committee on Highway Capacity and Quality of Service. It can be ordered by visiting the Publications section of the Transportation Research Board website.

SIDRA INTERSECTION is compatible with the US Highway Capacity Manual (HCM). However, unlike some software packages available in the USA, the HCM version of SIDRA INTERSECTION does not claim to be a simple replication of the HCM procedures. This means that:

• Generally (for all types of intersection), SIDRA INTERSECTION uses more advanced models and methods, including lane-by-lane analysis rather than analysis by lane groups, modeling of short lanes, detailed modeling of geometric delays, and the use of drive cycles (cruise, acceleration, deceleration and idling) for detailed modelling of delay and travel time components as well as operating cost, fuel consumption and emission estimation.
• The HCM version of SIDRA INTERSECTION is based on the calibration of most model parameters using the HCM defaults as applicable.
• SIDRA INTERSECTION includes various configuration options to allow the user to choose between the HCM and standard SIDRA model options, e.g. the HCM Delay and Queue model options.
• The HCM 2010 roundabout capacity model is fully integrated in SIDRA INTERSECTION with significant extensions (see below).
• For signalised intersections, in addition to the general features mentioned above, advanced signal timing methods are available, and the use of two green periods for modeling slip lanes, RTOR and permitted-protected left-turns provides more accurate capacity estimates.
• Some HCM models or methods are used in all versions of SIDRA INTERSECTION, including the HCM Level of Service method and criteria, the delay and queue progression factors, and All-Way Stop Control (AWSC) analysis method (the SIDRA AWSC model is currently based on the HCM 1994 edition, and there are some differences between the SIDRA and HCM two-way stop control models).
• The HCM and SIDRA INTERSECTION capacity and performance models are compatible in their basic structures and principles (e.g. the HCM back of queue model for signalised intersections was derived from the SIDRA INTERSECTION model), and although SIDRA INTERSECTION is a much more detailed model than the HCM, SIDRA INTERSECTION works like a more advanced version of the HCM by incorporating the HCM defaults in its HCM version.

A detailed paper on the HCM version of SIDRA was published by Akcelik (1990).  Some aspects of this paper are outdated due to the changes introduced in later editions of HCM and the adoption of those changes in SIDRA INTERSECTION.

Detailed explanations related to all aspects of the HCM version of SIDRA INTERSECTION are included throughout the User Guide.

You can find a glossary of terms based on the 2000 edition of the Highway Capacity Manual on our website:

Highway Capacity Manual Glossary A-H

Highway Capacity Manual Glossary I-Z

TRB Highway Capacity Manual 2010 (HCM 2010) has been published recently, and a full implementation of the new roundabout capacity model described in the manual is available in SIDRA INTERSECTION 5.1. This new version of the software offers powerful extensions to the HCM 2010 methodology to enhance your roundabout design capabilities.

The roundabout capacity model is the only analysis method in HCM 2010 which uses lane-by-lane analysis, and as such it is best implemented by SIDRA INTERSECTION which has been using a lane-by-lane methodology for all types of intersection since 1980s.

The Highway Capacity Manual (HCM) versions of SIDRA INTERSECTION use the HCM 2010 roundabout capacity model as the default model. It also continues to offer the SIDRA Standard model with a default Environment Factor of 1.2 to match the lower capacity estimates based on US roundabout research.

The extensions of the HCM 2010 roundabout model available in SIDRA INTERSECTION are listed in the HCM 2010 Roundabout Capacity Model page.  A summary can be found in the following document:

 Integration of the new HCM 2010 roundabout capacity model into SIDRA INTERSECTION 5.1.pdf 

he HCM Delay Formula and HCM Queue Formula options in SIDRA INTERSECTION will cause delays and queues for signalised intersections, roundabouts and two-way stop-sign control to be calculated using the HCM equations regardless of the model setup chosen. Otherwise, the standard SIDRA INTERSECTION delay and queue equations will be used in all cases. For further information, refer to the SIDRA INTERSECTION User Guide.

The signalised intersection chapter of the Highway Capacity Manual includes a back of queue model which was developed by Akçelik (1995, 1996). The HCM back of queue model for signalised intersections will be used instead of the standard SIDRA INTERSECTION model when the HCM Queue Formula option is selected. The two models are based on the same modelling methodology and give close results.

HCM does not give back of queue models for roundabouts and sign-controlled intersections. For model consistency, the standard SIDRA INTERSECTION back of queue model will be used for roundabouts and sign-controlled intersections rather than the cycle-average queue given in the HCM. However, the results of this back of queue model are unique to the HCM versions of SIDRA INTERSECTION since the model uses parameters based on the defaults used in the HCM versions of the software. For example, for roundabouts, gap-acceptance parameters of the HCM 2010 roundabout capacity model are used in the back of queue model.

AKÇELIK, R. (1990). SIDRA for the Highway Capacity Manual. Compendium of Technical Papers, 60th Annual Meeting of the Institute of Transportation Engineers, pp. 210–219.

AKÇELIK, R. (1995). Extension of the Highway Capacity Manual Progression Factor Method for Platooned Arrivals. Research Report ARR No. 276. ARRB Transport Research Ltd, Vermont South, Australia.

AKÇELIK, R. (1996). Progression factor for queue length and other queue-related statistics. Transportation Research Record 1555, pp 99-104.

TRB (2010). Highway Capacity Manual. Transportation Research Board, National Research Council, Washington, DC, USA. ["HCM 2010"]

TRB (2010). Roundabouts: An Informational Guide. NCHRP Report 672. Transportation Research Board, Washington, DC, USA.