U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
|Table of Contents | Previous | Next|
Note: This document summarizes current practices but does not set standards; practitioners are advised to check current local standards and requirements (refer to Disclaimer and Quality Assurance Statement). Users of the data provided within this document should anticipate possible variations from current information within the FRA databases, which are updated monthly.
This chapter discusses methods for selecting alternatives and provides information on MUTCD Interpretations, Experimentation, Changes, and Interim Approvals, which provide the best source of new guidance between updates to the MUTCD.
Methods to evaluate and select alternatives through engineering study and economic analysis techniques which are presented include the following:
Although procedures are provided for developing benefit-cost analyses of alternative treatments, more recent trends place emphasis on risk avoidance and best practices. As a result, benefit-cost studies may only be useful for evaluating alternatives that involve a major investment. In addition, the Rail-Highway Crossing Resource Allocation Procedure is presented and other low-cost solutions are discussed.
More involved economic analyses such as Benefit-Cost Analysis, Resource Allocation Procedures, and use of GradeDec may be more appropriate approaches to utilize when looking at multi-crossing scenarios, such as rail corridors or statewide efforts, or when considering tradeoffs between at-grade improvements vs. closures and grade separations.
The Technical Working Group TWG guidance, which relies upon readily available planning data, can provide a good initial approach.
Confirmation of treatments should include a field review using the Diagnostic Team Review procedure.
Following the 1995 collision in Fox River Grove, IL, between a Metra commuter train and a school bus, which resulted in the deaths of seven students, the USDOT established a Technical Working Group (TWG) to develop "best practices" guidance on a selection of crossing treatments. The TWG included representatives from the FHWA, FRA, FTA, and NHTSA, along with traffic engineers and rail signaling engineers with a working knowledge of crossing treatments. The cooperation among the various representatives of the TWG represented a landmark interdisciplinary effort to enhance communication among railroad companies and governmental agencies involved in enhancing grade crossing safety.
The guidance developed by the TWG notes that a highway-rail crossing differs from a highway-highway intersection in that the train always has the ROW. From this perspective, the TWG highlights key considerations for deciding what type of highway traffic control device(s) are to be installed, if in fact a grade crossing should be allowed to remain. This, in turn, requires an assessment of what information the road user (specifically nonâ€‘motorized system users) needs to be able to cross safely and whether the resulting driver response to a traffic control device is "compatible" with the intended function of the highway and railroad facility. The TWG guidance outlines the role of stopping sight distance, approach (corner) sight distance, and clearing sight distance, and integrates this with highway system needs based upon the type and classification of the roadway as well as the allowable track speeds by class of track for the railway system.
The TWG guidance provided in this Handbook has been updated to reflect current practice. It is intended to assist engineers in the selection of traffic control devices or other measures at highway-rail crossings. It is not to be interpreted as policy or standards and is not mandatory. Any requirements that may be noted are taken from the MUTCD or other standards. A number of measures are included which may not have been supported by quantitative research but are being used by States and local agencies. This TWG guidance is for information purposes only.
Minimum Devices: All highway-rail crossings, including street-running railroads or transit systems on public streets or highways should be equipped with approved passive warning devices, as shown in MUTCD Part 8.
Minimum Widths: All highway-rail crossing surfaces should extend a minimum of 1 foot beyond the edge of the roadway shoulder, sidewalk, pathway or face of curb, as measured perpendicular to the roadway centerline.
Closure: Highway-rail crossings should be considered for closure and physically removed from the railroad right-of-way whenever one or more of the following apply:
It may be advisable to investigate whether to construct alternative roadway access in conjunction with closing the crossing when the subject crossing is currently the only access to a community.
Grade Separation: Grade separation should be provided at all limited access facilities and should be considered for whenever one or more of the following conditions exist:
Table 7. LRT Grade Separation
|Trains Per Hour||Peak-Hour Volume (Vehicles Per Lane)|
Source: Light Rail Transit Grade Separation Guidelines, An Informational Report. Washington, DC, ITE, Technical Committee 6A-42, March 1992.
If active devices are selected, a preempted traffic control signal without railroad warning devices may be appropriate if the following conditions exist:
If active devices are selected, railroad flashers without gates may be appropriate if the following conditions exist:
Roadway Realignment: In some circumstances, a crossing may have adverse geometric features which can be improved by realignment of the roadway. Examples include the following:
New Crossings: New highway-rail crossings should only be permitted when the following can be demonstrated:
If a crossing is permitted, the following conditions should apply:
Step 1–Minimum highway-rail crossing criteria:
1. Gather preliminary crossing data:
Traffic Control Device:
Prior Collision History
2. Based on one or more of the above, determine whether any of the recommended thresholds for closure, installing passive or active devices, or grade separation have been met based on highway or rail system operational requirements
3. Consider crossing closure based on the criteria noted earlier in this section
Step 2–Evaluate highway traffic flow characteristics:
1. Consider the required motorist response to the existing (or proposed) type of traffic control device. At passive crossings, determine the degree to which traffic may need to slow or stop based on evaluation of available corner sight distances
2. Determine whether the existing (or proposed) type of traffic control device and railroad operations will allow highway traffic to perform at an acceptable LOS for the functional classification of the highway
Step 3–Possible revision to the highway-rail crossing:
1. If crossing closure or consolidation is being considered, determine the feasibility and cost of providing of an acceptable alternate route and compare this to the feasibility, benefits of safety modifications and cost of improving the existing crossing
2. If grade separation is being considered:
3. If there is inadequate sight distance related to the type of control device for stopping, approach speed, or clearing, consider measures such as:
4. If active devices are being considered, the devices should be installed with consideration to what is discussed earlier in this section
The following discussion draws upon the research found in the Engineering Design for Pedestrian Safety at Highway-Rail Grade Crossings. (42) Pedestrian behavior at or adjacent to railroad tracks can be characterized as risky.
Six criteria regarding the pedestrian crossing environment and the desired devices and controls for it, were published by the Transit Cooperative Research Program in Report 69:(31)
Whereas the above criteria were developed for LRT applications, these criteria may be used to evaluate the need for commonly-used pedestrian treatments.
Devices and treatments identified in the Engineering Design for Pedestrian Safety at Highway-Rail Grade Crossings include the following:
Passive devices for pedestrian crossings
Active devices for pedestrian crossings
Pedestrian behavior that violates traffic control at crossings can undermine the effectiveness of treatments at crossings. It has been noted that new treatments installed to mitigate some types of risky pedestrian behavior result in new forms of risky behavior; for example, pedestrians may pull open a swing gate intended for emergency egress and evade a lowered pedestrian gate.
Determining the most applicable type of treatment to use is a site-specific decision based on several criteria, site assessments, and other noteworthy practices.
Current practice in crossing treatment selection utilizes the diagnostic study method. The approach centers on a field survey procedure using a "Diagnostic Team" composed of experienced individuals knowledgeable in key disciplines including crossing design, safety engineering, rail operations and signaling, and traffic engineering.
This approach is intended to ensure that site-specific features are considered in adapting guidance and standards for treatments to address the issues at a crossing. The diagnostic study method can also provide an interdisciplinary approach which reflects all the technical considerations in selection of a treatment alternative.
As such, the diagnostic study method, supported by additional engineering analyses conducted offsite, provides a structured approach which might satisfy the various requirements for "Engineering Study" as defined in the MUTCD (Part 1A.13). Refer to Appendix C of this Handbook for specific procedures.
An economic analysis may be performed to determine possible alternative improvements that could be made at a highway-rail crossing. The FHWA Highway Safety Benefit Cost Analysis Guide(43) and companion Highway Safety Benefit Cost Analysis Tool(44) and support materials available at the FHWA Highway Safety Improvement Program (HSIP) website can be used by practitioners to evaluate safety improvement alternatives. Practitioners need to assemble information on the following elements, using the following best available facts and estimates:
Other considerations include the effectiveness of the improvement in reducing collisions and the effects on travel, such as reducing delays.
The selection of collision cost values is of major importance in economic analyses. Considerable care should be used in establishing values for these costs. The following are the two most common sources of collision costs:
The NSC costs include wage losses, medical expenses, insurance administrative costs, and property damage. The NHTSA includes the calculable costs associated with each fatality and injury plus the cost to society, such as consumption losses of individuals and society at large caused by losses in production and the inability to produce. Many States have developed their own State-specific values. Whichever is selected, the values should be consistent with those used for other safety improvement programs. An appropriate method of discounting should be used to account for inflation and opportunity cost. The selected discount rate should be informed by current practices and should be documented as part of the analysis.
The service life of an improvement should be equal to the time that the improvement can affect collision rates. Both costs and benefits should be calculated for this time. Hence, the service life is not necessarily the physical life of the improvement. For highway-rail crossings, however, it is a reasonable assumption that the improvement would be equally effective over its entire physical life. Thus, selecting the service life equal to the physical life would be appropriate.
The selected service life can have a profound effect on the economic evaluation of improvement alternatives; therefore, it should be selected using the best available information.
Project costs should include initial capital costs and maintenance costs and should be considered life-cycle costs; in other words, all costs are distributed over the service life of the improvement. The installation cost elements include the following:
The maintenance costs are all costs associated with keeping the system and components in operating condition.
The salvage value may be an issue when a highway is upgraded or relocated, or a railroad line is abandoned. Salvage value is defined as the dollar value of a project at the end of its service life and, therefore, is dependent on the service life of the project. For crossing signal improvement projects, salvage values are generally very small. Due to the characteristics of crossing signals and control equipment as well as the liability concerns that arise from deploying signal equipment that has already been used, it is assumed that there is zero salvage value after 10 years.
In lieu of the economic analysis procedures described above, USDOT has developed a resource allocation procedure for highway-rail crossing improvements. The FRA's User's Guide, Rail-Highway Crossing Resource Allocation Procedure, Third Edition (1987), can be accessed here: https://www.fra.dot.gov/Elib/Document/1537. This procedure was developed to assist States and railroads in determining the effective allocation of federal funds for crossing traffic control improvements
The resource allocation model is designed to provide an initial list of crossing traffic control improvements that would result in the greatest collision reduction benefits based on cost-effectiveness considerations for a given budget. As designed, the results are checked by a diagnostic team in the field and revised as necessary. It should be noted that the procedure considers only traffic control improvement alternatives as described below:
Other improvement alternatives, such as removal of site obstructions, crossing surface improvements, illumination, and train detection circuitry improvements, are not considered in the resource allocation procedure.
The input data required for the procedure consists of the number of predicted collisions, the safety effectiveness of flashing-lights and automatic gates, improvement costs, and the amount of available funding.
The number of annual predicted collisions can be derived from the USDOT Accident Prediction Model or from any model that yields the number of annual collisions per crossing.
Safety effectiveness studies for the equipment used in the resource allocation procedure have been completed by USDOT, the California Public Utilities Commission, and William J. Hedley. Effectiveness factors are the percent reduction in collisions occurring after the implementation of the improvement.
The model requires data on the costs of the improvement alternatives. Life-cycle costs of the devices should be used, such as both installation and maintenance costs.
Costs used in the resource allocation procedure are usually developed for each of the following three alternatives, as applicable:
1 Practitioners are cautioned to determine whether use of flashing lights without gates is appropriate for such locations; refer to the Technical Working Group guidance in this section.
Caution should be exercised in developing specific costs for a few selected projects while assigning average costs to all other projects. If this is done, decisions regarding the adjusted crossings may be unreasonably biased by the algorithm.
The amount of funds available for implementing crossing signal projects is the fourth input for the resource allocation procedure are at multiple track crossings.
The discussion which follows assumes that a group of crossings, some of which are at single-track sections and others where there are two or more tracks are being evaluated and that some crossings are passive whereas others have flashing-lights but no gates. The goal of the analysis is to prioritize crossings for improvement based upon cost-effectiveness, as explained further below.
If, for example, a single-track passive crossing is considered, it could be upgraded with either flashing-lights, with an effectiveness of E1, or gates, with an effectiveness of E2. The number of predicted collisions at crossing "i" is Ai. Therefore, the reduced accidents per year is AiE1 for the flashing-light option and AiE2 for the gate option. The corresponding costs for these two improvements are C1 and C2. The accident reduction/cost ratios for these improvements are AiE1/C1 for flashing-lights and AiE2/C2 for gates. The rate of increase in accident reduction versus costs that results from changing an initial decision to install flashing-lights with a decision to install gates at the crossing is referred to as the incremental accident reduction/cost ratio and is equal to:
If, on the other hand, the crossing was a passive crossing in multiple-track territory, then improvements to flashing-lights would not be an option. In this scenario, the upgrade from passive to gates would result in an effectiveness of E2, a cost of C2, and an accident reduction/ cost ratio of AiE2/C2. If this multi-track crossing was originally a flashing-light crossing, the improvement from flashing-lights to gates would be characterized with an effectiveness of E3, a cost of C3, and an accident reduction/cost ratio of AiE3/C3.
The individual accident reduction/cost ratios associated with these improvements are selected by the algorithm in an efficient manner to produce the maximum accident reduction that can be obtained for a predetermined total cost. This total cost is the sum of an integral number of equipment costs (C1, C2, and C). The total maximum accident reduction is the sum of the individual accident reductions of the form AxE.
The USDOT Rail-Highway Crossing Resource Allocation Procedure, as described in the Rail-Highway Crossing Resource Allocation Procedure's Guide, Third Edition, August 1987, DOT/ FRA/OS-87/10, uses three "normalizing constants" in the accident prediction formula.(45) These constants need to be adjusted periodically to keep the procedure matched with the current accident trends, the current number of open public at-grade crossings, and the changes in the warning devices.
For the most recently calculated 2013 normalizing constants, the collision data that was used was for calendar years 2007-2011 (to predict 2012 accidents/incidents). The process of determining the three new normalizing constants for 2013 was performed such that the sum of the 2012 accident prediction values of all open public at-grade crossings in the National Highway Rail Crossing Inventory data that was used was made to equal the sum of the observed number of collisions. Note that while mismatched data records between accident/inventory reporting are included, those accidents which occurred prior to the date of a warning device change are excluded, and also excluded are accidents which occurred at closed crossings and nonpublic at-grade crossings as included in the Inventory data used. This process was performed for each of the respective formulae for the three types of warning device categories: passive, flashing-lights, and gates. This process normalizes the calculated predictions for the current trend in collision data for each category and relative to each of the three types of warning device categories (see Table 8).
Table 8. Collision Prediction and Resource Allocation Procedure Normalizing Constants
|Warning Device Groups||New*||Prior years|
Source: Federal Railroad Administration websit (http://safetydata.fra.dot.gov/officeofsafety/default.aspx).
The most current Normalizing Constants are used in FRA's Web Accident Prediction System (WBAPS), on the FRA Safety Data website. Practitioners are encouraged to access this system which can provide the risk reduction factors based upon data in the USDOT grade crossing database.(46) If the resource allocation procedure is used to identify high-hazard crossings, a field diagnostic team should investigate each selected crossing for accuracy of the input data and reasonableness of the recommended solution. A worksheet for performing this analysis is included in Figure 61 (or download from this link https://safety.fhwa.dot.gov/hsip/xings/com_roaduser/07010/sec05form3.pdf).
This worksheet also includes a method for manually evaluating or revising the results of the computer model.
Figure 61. Resource Allocation Procedure Field Verification Worksheet
Source: FRA webste.
The FRA developed the GradeDec.NET (GradeDec) highway-rail grade crossing investment analysis tool to provide grade crossing investment decision support. The GradeDec provides a full set of standard benefit-cost metrics for a rail corridor, a region, or an individual grade crossing. Model output allows a comparative analysis of grade crossing alternatives designed to mitigate highway-rail grade crossing collision risk and other components of user costs, including highway delay and queuing, air quality, and vehicle operating costs. The online application can be accessed via FRA's website.(47)
The GradeDec is intended to assist State and local transportation planners in identifying the most efficient grade crossing investment strategies. The GradeDec modeling process can encourage public support for grade crossing strategies, including closure and separation, where project success often depends on getting the community involved in the early planning stages. The GradeDec computes model output using a range of values for many of the model inputs. This process allows individual stakeholders to influence how different investment options are weighed and evaluated.
The GradeDec implements the corridor approach to reducing collision risk that was developed as part of the Transportation Equity Act for the 21st Century's Next-Generation High-Speed Rail Program (TEA-21, 1998, PL, 105-178). This approach can be an effective means of reducing the overall capital costs involved in constructing facilities for high-speed passenger rail service (at speeds between 111 and 125 mph), where grade crossing hazards and mitigation measures can be a major cost factor.
The corridor approach can be used to demonstrate that acceptable levels of collision risk have been reached for all rail corridors, train types, and speeds. For example, exceptions to the proposed federal rule mandating whistle-sounding at all highway-rail grade crossings can be made by showing that appropriate safety measures have been taken to mitigate the additional risk otherwise presented by trains not sounding their horns.
The GradeDec uses simulation methods to analyze project risk and generate probability ranges for each model output, including B/C ratios and net present value. The software also analyzes the sensitivity of project risk to GradeDec 2000 model inputs to inform users which factors have the greatest impact on project risk.(48)
As technology and research continue to progress, updates to guidance and standards outlined in this Handbook, as well as the MUTCD, may be required. The FHWA periodically updates the MUTCD; however, updates to the document must go through a federal "rulemaking" process which requires posting the document in a Notice of Proposed Action (NPA) and addressing comments received before posting the revised document as a "Final Rule." A number of years may be required to provide a full update to the MUTCD.
The 2009 MUTCD with revisions 1 and 2 is available at https://mutcd.fhwa.dot.gov/pdfs/2009r1r2/pdf_index.htm.
It should be noted that a "hotlinks" PDF version of the MUTCD which contains the most current updates to the MUTCD providing links to official interpretations, corrections to known errors, and other external documents is available at https://mutcd.fhwa.dot.gov/pdfs/2009r1r2/hotlinksfeatures.htm.
During the intervening period between MUTCD updates, FHWA may provide "Interpretations" or "Interim Approvals" and practitioners may petition FHWA to conduct "Experimentation" for a new treatment following procedures presented in Section 1A.10 of the MUTCD
Practitioners should be aware of the following:
|Table of Contents | Previous | Next|