U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
| Railroad-Highway Grade Crossing Handbook - Revised Second Edition August 2007 | |
| Section 4: Identification of Alternatives (continued) | Table of Contents | Previous | Next |
J. Pedestrian and Bicycle Considerations
Non-motorist crossing safety should be considered at all highway-rail grade crossings, particularly at or near commuter stations and at non-motorist facilities, such as bicycle/walking trails, pedestrian-only facilities, and pedestrian malls.
Passive and active devices may be used to supplement highway-related active control devices to improve non-motorist safety at highway-rail crossings. Passive devices include fencing; swing gates; pedestrian barriers; pavement markings and texturing; refuge areas; and fixed message signs. Active devices include flashers; audible active control devices; automated pedestrian gates; pedestrian signals; variable message signs; and blank-out signs.
These devices should be considered at crossings with high pedestrian traffic volumes; high train speeds or frequency; extremely wide crossings; complex highway-rail grade crossing geometry with complex right-of-way assignment; school zones; inadequate sight distance; and/or multiple tracks. All pedestrian facilities should be designed to minimize pedestrian crossing time, and devices should be designed to avoid trapping pedestrians between sets of tracks.
Guidelines for the use of active and passive devices for non-motorist signals and crossings are found in MUTCD Section 10D, Part 10.108
In the event that a grade crossing is included in a roundabout, design considerations include the provision of traffic control (such as crossing gates and flashing lights) at the grade crossing consistent with treatments at other highway-rail grade crossings. In addition, where queuing could occur (such as gridlocking within the roundabout), additional measures may be necessary up to and including the installation of supplementary devices such as traffic signals to preclude blockages of the track that cannot be cleared in advance of the arrival of a train.
At the June 2006 meeting of NCUTCD, the council approved provisions that would require an engineering study of the potential for traffic to back up across a grade crossing due to a roundabout and the identification of appropriate countermeasures, including possible use of traffic signals.
L. Site and Operational Improvements
In addition to the installation of traffic control systems, site and operational improvements can contribute greatly to the safety of highway-rail grade crossings. Site improvements are discussed in four categories: removing obstructions, crossing geometry, illumination, and safety barriers.
1. Removing Obstructions
The following text identifies treatments to address various sight distance needs, previously discussed in Chapter III as part of the diagnostic study method.
Approach. To permit this, three areas of the crossing environment should be kept free from obstructions. The area on the approach from the driver ahead to the crossing should be evaluated to determine whether it is feasible to remove any obstructions that prevent the motorist from viewing the crossing ahead, a train occupying the crossing, or active control devices at the crossing.
Clutter is often a problem in this area, consisting of numerous and various traffic control devices, roadside commercial signing, utility and lighting poles, and vegetation. Horizontal and vertical alignment can also serve to obstruct motorists' view of the crossing. Clutter can often be removed with minimal expense, improving the visibility of the crossing and associated traffic control devices. Traffic control devices unnecessary for the safe movement of vehicles through the crossing area should be removed. Vegetation should be removed or cut back periodically. Billboards should be prohibited on the approaches.
Corner. View obstructions often exist within the sight triangle, typically caused by structures; topography; crops or other vegetation (continually or seasonal); movable objects; or weather (fog or snow). Where lesser sight distances exist, motorists should reduce speed and be prepared to stop not less than 4.5 meters (15 feet) before the near rail, unless and until they are able to determine, based upon the available sight distance, that there is no train approaching and it is safe to proceed. Wherever possible, sight line deficiencies should be improved by removing structures or vegetation within the affected area, regrading an embankment, or realigning the highway approach.
Many conditions, however, cannot be corrected because the obstruction is on private property or it is economically infeasible to correct the sight line deficiency. If available corner sight distance is less than what is required for the legal speed limit on the highway approach, supplemental traffic control devices such as enhanced advance warning signs, STOP or YIELD signs, or reduced speed limits (advisory or regulatory) should be evaluated. If it is desirable from traffic mobility criteria to allow vehicles to travel at the legal speed limit on the highway approach, active control devices should be considered.109
Changes to horizontal and vertical alignment are usually more expensive. However, when constructing new highways or reconstructing existing highways, care should be taken to minimize the effects of horizontal and vertical curves at a crossing.
The approach sight triangle is the second area that should be kept free from obstructions. This area provides an approaching motorist with a view of an approaching train. It can encompass a large area that is usually privately owned. In rural areas, this sight triangle may contain crops or farm equipment that block the motorist's view. For this reason, clearing the sight triangle may be difficult to achieve. However, obstructions should be removed, if possible, to allow vehicles to travel at the legal speed limit for the approach highway. Vegetation can be removed or cut back periodically, billboards and parking should be prohibited, and small hills may be regraded.
Clearing sight distance. The third area of concern is the clearing sight distance, which pertains to the visibility available to a highway user along the track when stopped ahead of the grade crossing. Usually, this area is located on railroad right of way. Vegetation is often desired along railroad right of way to serve as an environmental barrier to noise generated from train movements. However, the safety concern at crossings is of more importance and, if possible, vegetation should be removed or cut back periodically. Also, if practical, this sight distance area should be kept free of parked vehicles and standing railroad cars. Care should be taken to avoid the accumulation of snow in this area.
Vehicle acceleration data have been interpreted from the Traffic Engineering Handbook. The person or agency evaluating the crossing should determine the specific design vehicle, pedestrian, bicyclist, or other non-motorized conveyance and compute clearing sight distance, if it is not represented in Table 41. Note that the table values are for a level, 90-degree crossing of a single track. If other circumstances are encountered, the values must be recomputed.
If there is insufficient clearing sight distance, and the driver is unable to make a safe determination to proceed, the clearing sight distance needs to be improved to safe conditions or flashing light signals with gates, closure, or grade separation should be considered. (Refer to the guidance developed by the U.S. DOT Technical Working Group presented in Chapter V.)
An engineering study, as described in Chapter III, should be conducted to determine if the three types of sight distance can be provided as desired. If not, other alternatives should be considered. The highway speed might be reduced, through the installation of either an advisory or regulatory speed sign, to a level that conforms to the available sight distance. It is important that the motorist understand why the speed reduction is necessary, otherwise, it may be ignored unless enforced. At crossings with passive control devices only, consideration might be given to the installation of active traffic control devices that warn of the approach of a train.
2. Crossing Geometry
The ideal crossing geometry is a 90-degree intersection of track and highway with slight-ascending grades on both highway approaches to reduce the flow of surface water toward the crossing. Few crossings have this ideal geometry because of topography or limitations of right of way for both the highway and the railroad. Every effort should be made to construct new crossings in this manner. Horizontal and vertical alignment and cross-sectional design are discussed below.
Table 41. Clearing Sight Distance (in feet)*
Train speed |
Car |
Single-unit truck |
Bus |
WB-50 semitruck |
65-foot |
Pedestrian** |
10 |
105 |
185 |
200 |
225 |
240 |
180 |
20 |
205 |
365 |
400 |
450 |
485 |
355 |
25 |
255 |
455 |
500 |
560 |
605 |
440 |
30 |
310 |
550 |
600 |
675 |
725 |
530 |
40 |
410 |
730 |
795 |
895 |
965 |
705 |
50 |
515 |
910 |
995 |
1,120 |
1,205 |
880 |
60 |
615 |
1,095 |
1,195 |
1,345 |
1,445 |
1,060 |
70 |
715 |
1,275 |
1,395 |
1,570 |
1,680 |
1,235 |
80 |
820 |
1,460 |
1,590 |
1,790 |
1,925 |
1,410 |
90 |
920 |
1,640 |
1,790 |
2,015 |
2,165 |
1,585 |
* A single track, 90-degree, level crossing.
** Walking 1.1 meters per second (3.5 feet per second) across two sets of tracks 15 feet apart, with a 2-second reaction time to reach a decision point 3 meters (10 feet) before the center of the first track, and clearing 3 meters (10 feet) beyond the centerline of the second track. Two tracks may be more common in commuter station areas where pedestrians are found.
Source: Guidance on Traffic Control Devices at Highway-Rail Grade Crossings. Washington, DC: Federal Highway Administration, Highway/Rail Grade Crossing Technical Working Group, November 2002.
Horizontal alignment. Desirably, the highway should intersect the tracks at a right angle with no nearby intersections or driveways. This layout enhances the driver's view of the crossing and tracks and reduces conflicting vehicular movements from crossroads and driveways. To the extent practical, crossings should not be located on either highway or railroad curves. Roadway curvature inhibits a driver's view of a crossing ahead, and a driver's attention may be directed toward negotiating the curve rather than looking for a train. Railroad curvature inhibits a driver's view down the tracks from both a stopped position at the crossing and on the approach to the crossing. Crossings located on both highway and railroad curves present maintenance problems and poor rideability for highway traffic due to conflicting superelevations. Similar difficulties arise when superelevation of the track is opposite to the grade of the highway.
If the intersection between track and highway cannot be made at right angles, the variation from 90 degrees should be minimized. One state limits the minimum skew to 70 degrees. At skewed crossings, motorists must look over their shoulder to view the tracks. Because of this more awkward movement, some motorists may only glance quickly and not take necessary precaution.
Generally, improvements to horizontal alignment are expensive. Special consideration should be given to crossings that have complex horizontal geometries, as described previously. These crossings may warrant the installation of active traffic control systems or, if possible, may be closed to highway traffic.
Vertical alignment. It is desirable that the intersection of highway and railroad be made as level as possible from the standpoint of sight distance, rideability, and braking and acceleration distances. Drainage would be improved if the crossing were located at the peak of a long vertical curve on the highway. Vertical curves should be of sufficient length to ensure an adequate view of the crossing and consistent with the highway design or operating speed.
Track maintenance can result in raising the track as new ballast is added to the track structure. Unless the highway profile is properly adjusted, this practice will result in a “humped” profile that may adversely affect the safety and operation of highway traffic over the railroad.
Two constraints often apply to the maintenance of grade crossing profiles: drainage requirements and resource limitations. Coordination of maintenance activities between rail and highway authorities, especially at the city and county level, is frequently informal and unstructured. Even when the need to coordinate has been identified, there may be a lack of knowledge regarding whom to contact.
In some cases, highway authorities become aware of increases in track elevation (a by-product of track maintenance) only after the fact. As a result, even if state standards exist, there is little opportunity to enforce them. Often, an individual increase in track elevation may not violate a guideline, but successive track raises may create a high-profile crossing.
Low-clearance vehicles, such as those low to the ground relative to the distance between axles, pose the greatest risk of becoming immobilized at highway-rail grade crossings due to contact with the track or highway surface. With the exception of specialized vehicles such as tank trucks, there is little standardization within the vehicle manufacturing industry regarding minimum ground clearance. Instead, manufacturers are guided by the requirements of shippers and operators.110
A similar problem may arise where the crossing is in a sag vertical curve. In this instance, the front or rear overhangs on certain vehicles may strike or drag the pavement.111
Alternatives to this problem include a design standard that deals with maximum grades at the crossing; prohibiting truck trailers with a certain combination of underclearance and wheelbase from using the crossing; setting trailer design standards; posting warning signs in advance of the crossing; minimizing the rise in track due to maintenance operations; or reconstructing the crossing approaches.112
The AREMA Manual for Railway Engineering recommends that the crossing surface be in the same plane as the top of rails for a distance of 600 millimeters (2 feet) outside of the rails, and that the surface of the highway be not more than 75 millimeters (3 inches) higher or lower than the top of the nearest rail at a point 7.5 meters (30 feet) from the rail, unless track superelevation dictates otherwise. This standard has been adopted by AASHTO in A Policy on Geometric Design of Highways and Streets (see Figure 56).113
Eck and Kang surveyed a large number of low-clearance vehicles on an interstate route in West Virginia and also obtained vehicle length and ground clearance data from Oregon and other sites. Based on field and engineering data, they proposed a low-clearance vehicle for design purposes that would have an 11-meter (36-foot) wheelbase and a 125-millimeter (5-inch) ground clearance.114
Eck and Kang also identified and summarized a number of state and railroad crossing profile standards in addition to the AREMA and AASHTO criteria described above. Among them were:
• The Illinois Commerce Commission specifies that from the outer rail of the outermost track, the road surface should be level for about 600 millimeters (24 inches). From there, for a distance of 7.6 meters (25 feet), a maximum grade of 1 percent is specified. From there to the railroad right-of-way line, a maximum grade of 5 percent is specified.
• The Division of Highways in West Virginia recommends 3 meters (10 feet) of run-off length for every 25 millimeters (1 inch) of track raise.
• A standard developed by the Southern Pacific Railroad prior to its merger with Union Pacific recommends that for a distance of 6 meters (20 feet) from a point 2 feet from the near rail, the maximum descent should be 150 millimeters (6 inches). From that point, for a distance of another 6 meters, the maximum descent should be 600 millimeters (2 feet).
• Tennessee state law requires that the road be graded level with the rails for a distance of 3 meters (10 feet) on either side of the track and between the rails thereof.
• A number of European countries have developed geometric design guidelines for highway-rail grade crossings. Great Britain provides a circular curve roadway profile. There are three categories of radii depending on traffic volume and traffic “moment” (the product of vehicular and rail traffic).
Eck and Kang developed a software package for the analysis of crossing profiles. HANGUP was developed to simulate the movement of low-clearance vehicles on grade crossings. It is useful as an analysis tool for evaluating crossings where low-clearance vehicles or overhang dragging may be a problem.115 At the time of this writing, the program package was being updated.
Figure 56. Highway-Rail Grade Crossing Cross Section
Source: From A Policy on Geometric Design of Highway and Streets, 2004, by the American Association of State Highway and Transportation Officials, Washington, DC. Used by permission.
Right of way and roadside (clear zone). The railroad and roadway rights of way at highway-rail grade crossings were usually purchased at the time the transportation facilities were built. Right-of-way restrictions frequently constrain the type and location of improvements that can be constructed. Within these rights of way the area adjacent to the crossing should be kept as level and free from obstructions as possible, subject to the space required for traffic control devices.
Although every reasonable effort must be made to keep a vehicle on the roadway railroad and highway engineers must acknowledge the fact that this goal will never be fully realized. Once a vehicle leaves the roadway the probability of a collision occurring depends primarily on the speed and trajectory of the vehicle and what lies in its path. If a collision does occur, its severity is dependent upon several factors, including the use of restraint systems by vehicle occupants, the type of vehicle, and the nature of the roadside environment. Of these factors, the engineer generally has control over only one: the roadside environment.
Ideally, the roadside recovery area, or “clear zone,” should be free from obstacles such as unyielding sign and luminaire supports, non-traversable drainage structures, trees larger than 100 millimeters (4 inches) in diameter, utility or railroad line poles, or steep slopes. Design options for mitigating these features are generally considered in the following order:
• Remove the obstacle or redesign it so that it can be safely traversed.
• Relocate the obstacle to a point where it is less likely to be struck.
• Reduce impact severity by using an appropriate breakaway device.
• Redirect a vehicle by shielding the obstacle by use of a longitudinal barrier or crash cushion.
• Delineate the obstacle if the above alternatives are not appropriate.
Highway and railroad officials must cooperatively decide on the type of traffic control devices needed at a particular crossing. As a minimum, crossbucks are required and should be installed on an acceptable support. Other traffic control device supports, such as for flashers or gates, can cause an increase in the severity of injuries to vehicle occupants if struck at high speeds. In these cases, consideration should be given to shielding the support with a crash cushion if the support is located in the clear zone. Longitudinal barriers are not often used because there is seldom room for a proper downstream end treatment, a longer hazard is created by installing a guardrail, and a vehicle striking a longitudinal barrier when a train is occupying the crossing may be redirected into the train.116 A longitudinal guardrail should not be used at a crossing unless it is otherwise warranted, such as by a steep embankment.
A curb over 100 millimeters (4 inches) tall is not an acceptable treatment where speeds are high because it will cause vehicles to vault. Any curb (including one less than 4 inches tall) can cause vehicles to go airborne if struck at high speed. Curbs should be avoided on high-speed roads but, if needed, the curb can be located at the back of the shoulder. In some cases, curbs closer to the traveled way may be acceptable on a high-speed road where they fulfill an important function, such as blocking an illegal or undesirable traffic movement.
The purpose of a traffic barrier such as a guardrail is to protect the errant motorist by containing or redirecting the vehicle. The purpose is not to protect traffic control devices against collision or possible damage. The ring type guardrail placed around a signal mast may create the same type of hazard as the mast itself; that is, the guardrail may be a roadside obstacle. These guardrails do, however, serve to protect the signal mast. Because functioning devices are vital to safety, the ring type guardrail may be used at locations with heavy traffic, such as an industrial area, and low traffic speeds.
More information can be obtained from the Roadside Design Guide, published by AASHTO.
3. Illumination
Illumination at a crossing may be effective in reducing nighttime collisions. Illuminating most crossings is technically feasible because more than 90 percent of all crossings have commercial power available. Illumination may be effective under the following conditions:
• Nighttime train operations.
• Low train speeds.
• Blockage of crossings for long periods at night.
• Collision history indicating that motorists often fail to detect trains or traffic control devices at night.
• Horizontal and/or vertical alignment of highway approach such that vehicle headlight beam does not fall on the train until the vehicle has passed the safe stopping distance.
• Long dark trains, such as unit coal trains.
• Restricted sight or stopping distance in rural areas.
• Humped crossings where oncoming vehicle headlights are visible under trains.
• Low ambient light levels.
• A highly reliable source of power.
Luminaires may provide a low-cost alternative to active traffic control devices on industrial or mine tracks where switching operations are carried out at night.
Luminaire supports should be placed in accordance with the principles in the Roadside Design Guide and NCHRP Report 350.117 If they are placed in the clear zone on a high-speed road, they should be breakaway.
4. Shielding Supports for Traffc Control Devices
The purpose of a traffic barrier, such as a guardrail or crash cushion, is to protect the motorist by redirecting or containing an errant vehicle. The purpose is not to protect a traffic control device against collision and possible damage. The use of a traffic barrier should be limited to situations in which hitting the object, such as a traffic control device, is more hazardous than hitting the traffic barrier and, possibly, redirecting the vehicle into a train.
A longitudinal guardrail should not be used for traffic control devices at crossings unless the guardrail is otherwise warranted, as for a steep embankment. The longitudinal guardrail might redirect a vehicle into a train.
On some crossings, it may be possible to use crash cushions to protect the motorist from striking a traffic control device. Some crash cushions are designed to capture rather than redirect a vehicle and may be appropriate for use at crossings to reduce the redirection of a vehicle into the path of a train.
The ring type guardrail placed around a signal mast may create the same type of hazard as the signal mast itself (the guardrail may be a roadside obstacle). It does, however, serve to protect the signal mast. Because functioning devices are vital to safety, the ring type guardrail may be used at locations with heavy industrial traffic, such as trucks, and low highway speeds.
When a barrier is used, it should be installed according to the requirements in the Guide for Selecting, Locating and Designing Traffic Barriers.
In negotiating a crossing, the degree of attention the driver can be expected to devote to the crossing surface is related to the condition of that surface. If the surface is uneven, the driver's attention may be devoted primarily to choosing the smoothest path over the crossing rather than determining if a train is approaching the crossing. This type of behavior may be conditioned; that is, if a driver is consistently exposed to uneven crossing surfaces, he or she may assume that all crossing surfaces are uneven whether or not they actually are. Conversely, if a driver encounters an uneven surface unexpectedly, he or she may lose control of the vehicle, resulting in a collision. Therefore, providing reasonably smooth crossing surfaces is viewed as one of several elements toward improving crossing safety and operations.
The AREMA Manual of Railway Engineering, Part 8, provides guidelines for the construction and reconstruction of highway-rail crossings. The first section of Part 8 provides information
on crossing surface materials; crossing width; profile and alignment of crossings and approaches; drainage; ballast; ties; rail; flange widths; and new or reconstructed track through a crossing. Other sections in this chapter cover traffic control devices for highway-railway grade crossings; protecting highway-railway grade crossings and flangeways; types of barrier for dead-end streets; specifications for permanent number of boards for the U.S. DOT– American Association of Railroads highway-railway crossings inventory system; location of highways parallel with railways; and problems related to location and construction of limited-access highways in the vicinity of or crossing railways.
Originally, crossing surfaces were made by filling the area between the rails with sand and gravel, probably from the railroad ballast. Later, crossing surfaces were made of planks or heavier timbers or of bituminous material, sometimes using planks to provide the flangeway openings. Treated timber panels and prefabricated metal sections followed and, in 1954, the first proprietary rubber panel crossing surface was put on the market. Presently available proprietary surfaces, usually patented, are fabricated from concrete, rubber, steel, synthetics, wood, and various combinations of these materials.
Crossing surfaces available today can be divided into two general categories: monolithic and sectional. Monolithic crossings are formed at the crossing and cannot be removed without destroying them. Typical monolithic crossings are asphalt, poured-in-place concrete, and cast-in-place rubber (elastomeric) compounds. Sectional crossings are manufactured in sections (panels), are placed at the crossing, and can be removed and re-installed. These crossing surfaces facilitate the maintenance of track through the crossing. Typical sectional crossings consist of treated timbers, reinforced concrete, steel, high-density polyethylene, and rubber.
Proper preparation of the track structure and good drainage of the subgrade are essential to good performance from any type of crossing surface. Excessive moisture in the soil can cause track settlement, accompanied by penetration of mud into the ballast section. Moisture can enter the subgrade and ballast section from above, below, and/or adjacent subgrade areas. To the extent feasible, surface and subsurface drainage should be intercepted and discharged away from the crossing. Drainage can be facilitated by establishing an adequate difference in elevation between the crossing surfaces and ditches or embankment slopes. The highway profile at all crossings should be such that water drains away from the crossing.
N. Removal of Grade Separation Structures
There are approximately 34,000 public grade-separated highway-rail crossings in the United States. More than half of these grade-separated crossings have a bridge or highway structure over the railroad tracks. As these structures age, become damaged, or are no longer needed because of changes in highway or railroad alignment or use, alternative engineering decisions must be made. The alternatives to be considered are upgrading the existing structure to new construction standards; replacing the existing structure; removing the structure, leaving an at-grade crossing; and closing the crossing and removing the structure.
In general, crossing programs are based upon criteria established for the installation of traffic control devices or the elimination of a crossing. However, rehabilitation of structures is a significant part of the crossing improvement program at both the state and the national level. Currently, there are no nationally recognized guidelines for evaluating the alternatives available for the improvement or replacement of grade-separation structures.
Some states have developed evaluation methods for the selection of projects to remove grade-separation structures. Following is a summary of the state of Pennsylvania guidance.
The purpose of the Pennsylvania guidance is to assist highway department personnel in the selection of candidate bridge removal projects where the railroad line is abandoned. Both bridges carrying highway over railroad and bridges carrying abandoned railroad over highway can be considered. The factors to be considered in selecting candidate projects are as follows:
For bridges carrying highway over an abandoned railroad:
• Bridges that are closed or posted for a weight limit because of structural deficiencies (the length of the necessary detour is important).
• Bridges that are narrow and, therefore, hazardous.
• Bridges with hazardous vertical and/or horizontal alignment of the highway approaches (accident records can be reviewed to verify such conditions).
For bridges carrying abandoned railroad over a highway:
• Bridges that are structurally unsound and a hazard to traffic operating under the bridge.
• Bridges whose piers and/or abutments are in close proximity to the traveled highway and constitute a hazard.
• Bridges whose vertical clearance over the highway is substandard.
• Bridges where the vertical and/or horizontal alignment of the highway approaches are hazardous primarily because of the location of the bridge.
It should be noted that this guidance is applicable to situations that involve abandoned rail lines.
In those instances where a railroad continues to operate, other decisions must be made. Some considerations for removing a grade separation over or under a rail line that is still being operated are as follows:
• Can the structure be removed and replaced with an at-grade crossing?
• Who is liable if an accident occurs at the new at-grade crossing?
• If the structure is to be rebuilt, who is to pay the cost or who is to share in the cost and to what extent?
• To what standards is the structure to be rebuilt?
• What is the future track use and potential for increase in train frequency?
• If the structure is replaced with an at-grade crossing, what delays to motorists and emergency service will result? Are alternate routes available?
• What impact will an at-grade crossing have on railroad operations?
• What will be the impact on safety of an at-grade crossing versus a structure?
To ensure a proper answer to these and other related questions, an engineering evaluation, including relative costs, should be conducted. This evaluation should follow procedures described in Chapter V.
American National Standard Practices for Roadway Lighting. New York, New York: Illuminating Engineering Society of America, July 1977.
Code of Federal Regulations, Title 23, Washington, DC: General Services Administration, published annually.
Collision of Amtrak Train No. 88 with Tractor Lowboy Semitrailer Combination Truck, Rowland, N.C., August 25, 1983. Washington, DC: National Transportation Safety Board, Report No. NTSB/RHR-84/01, 1984.
The Effectiveness of Automatic Protection in Reducing Accident Frequency and Severity at Public Grade Crossings in California. San Francisco, California: California Public Utilities Commission, June 1974.
Federal-Aid Policy Guide Program Manual. Washington, DC: Federal Highway Administration (FHWA), updated periodically.
Federal Highway Administration Survey of Region and Division Offices, unpublished, 1984.
Data from the U.S. DOT National Rail-Highway Crossing Inventory, Federal Railroad Administration (FRA), 1984.
Field and Office Manual for Profile Surveys of Highway-Rail At-Grade Crossings on Existing Paved Roadways. Tallahassee, Florida: Florida Department of Transportation, September 1984.
Fitzpatrick, Gary M. Standardization of Criteria for Rail/Highway Grade Crossing Construction. Tallahassee, Florida: Florida Department of Transportation, Office of Value Engineering, August 1982.
Guide for Selecting, Locating, and Designing Traffic Barriers. Washington, DC: American Association of State Highways and Transportation Officials, 1977.
Heathington, K.W. and T. Urbanik. “Driver Information Systems for Highway-Railway Grade Crossings.” Highway Research Record, No. 414. Washington, DC: Highway Research Board, 1972. Hedley, William J. Proceedings, American Railway Engineering and Maintenance-of-Way Association, Vol. 53, Chicago, Illinois, 1952.
Hedley, William J. Railroad-Highway Grade Crossing Surfaces. Washington, DC: FHWA, August 1979.
Illinois Commerce Commission General Order No. 138, Revised. Springfield, Illinois: Illinois Commerce Commission, 1973.
Knoblauch, Karl, Wayne Hucke, and William Berg. Rail Highway Crossing Accident Causation Study. Volume II, Technical Report. Washington, DC: FHWA, Report FHWA/RD-81/083, August 1982.
Manual for Railway Engineering. Washington, DC: American Railway Engineering and Maintenance-of-Way Association, 1981.
Manual on Uniform Traffic Control Devices, 2003 Edition. Washington, DC: FHWA, 2003.
Mather, Richard A. Public Railroad-Highway Grade Crossing Illumination Project in Oregon. Washington, DC: Transportation Research Board, January 1983.
Monroe, Richard L., Debra K. Munsell, and T. James Rudd. Constant Warning Time Concept Development for Motorist Warning at Grade Crossings. Washington, DC: FRA, Report FRA/ ORD-81/07, May 1981.
Morrissey, J. The Effectiveness of Flashing Lights and Flashing Lights with Gates in Reducing Accident Frequency at Public Rail-Highway Crossings, 1975-1978. Washington, DC: FRA and FHWA, April 1980.
A Policy on Geometric Design of Highway and Streets. Washington, DC: American Association of State Highway and Transportation Officials, 1984.
Proceedings, National Conference on Railroad-Highway Crossing Safety, Colorado Springs, Colorado, U.S. Air Force Academy Interim Education Center, August 1974.
Proceedings, National Conference on Railroad-Highway Crossing Safety, Salt Lake City, Utah, University of Utah, August 1977.
Proceedings, National Rail-Highway Crossing Safety Conference, Knoxville, Tennessee, The University of Tennessee, June 1980.
Rail-Highway Grade Crossing Warning Systems and Surfaces. Alexandria, Virginia: The Railway Progress Institute, 1983.
Roadway Lighting Handbook. Washington, DC: FHWA, Implementation Package 7815, December 1978.
Ruden, Robert J., Albert Burg, and John P. McGuire. Activated Advance Warning for Railroad Grade Crossings. Washington, DC: FHWA, Report FHWAI RD-80/003, July 1982.
Standard Alphabet for Highway Signs and Markings. Washington, DC: FHWA.
Traffic Control Devices Handbook. Washington, DC: FHWA, 1983.
Uniform Vehicle Code and Model Traffic Ordinance. National Committee of Uniform Traffic Laws and Ordinances, Charlottesville, Virginia: The Michie Company, 1961 and Supplement, 1979.
“Use of Traffic Divisional Islands at Railroad Grade Crossings.” Technical Notes 84-1. Albany, New York: New York Department of Transportation, March 1984.
West Virginia's Highway-Railroad Manual. Charleston, West Virginia: West Virginia Department of Highways, Railroad Section, Right of Way Division, preliminary, 1984.
108 Guidance on Traffic Control Devices at Highway-Rail Grade Crossings. Washington, DC: FHWA, Highway/Rail Grade Crossing Technical Working Group, November 2002.
109 Ibid.
110 “Accidents That Shouldn’t Happen.” A Report by the U.S. Department of Transportation (U.S. DOT) Task Force on Highway-Rail Crossing Safety to Transportation Secretary Federico Pena, March 1, 1996.
111 Eck, Ronald W. and S.K. Kang. “Low Clearance Vehicles at Grade Crossings.” West Virginia University, 1992.
112 “Accidents That Shouldn’t Happen.” A Report by the U.S. DOT Task Force on Highway-Rail Crossing Safety to Transportation Secretary Federico Pena, March 1, 1996.
113 A Policy on Geometric Design of Highways and Streets, 2004 Edition. Washington, DC: American Association of State Highway and Transportation Officials, 2004.
114 Eck, Ronald W. and Kang, S. K. “Low Clearance Vehicles at Grade Crossings.” West Virginia University, 1992.
115 Ibid.
116 Roadside Design Guide, Washington, DC: AASHTO, 2002.
117 Ibid.
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