CHAPTER 3

Bridge and Tunnel Strike Countermeasures

Once an agency identifies factors that contribute to BrTS, the next step is to identify appropriate countermeasures to target the underlying issue or issues. The key to effectively addressing risk is to identify countermeasures that directly target the risk factors at hand to a level that is commensurate with the level of risk at the location of interest. For instance, if a bridge is at high risk of being struck and a bridge strike would have significant impacts on operations, then an agency might consider two options: raising the bridge height during the next bridge replacement or installing turnarounds. The result of this step is a list of potential options, not the final recommendation.

Countermeasure selection starts with a larger list of options that are pared down to the preferred alternatives through more detailed analysis. This chapter focuses on the first part of the process—countermeasure identification. The next chapter focuses on the second part—alternatives analysis. This chapter begins with a discussion of general considerations and a summary of common BrTS risk factors with applicable countermeasures. The remainder of the chapter provides detailed descriptions of individual countermeasures, including cost, effectiveness, service life, and other considerations.

3.1 General Countermeasure Considerations

To inform countermeasure selection, agencies would consider the following (Atlanta Regional Commission 2022):

• Safe System principles: Countermeasures that align with Safe System principles are those that minimize the potential for crash frequency and severity, and build in redundancy (e.g., serve as a backup if another system component fails).
• Community context: Agencies should consider the surrounding land use, function of the roadway, and community context when selecting countermeasures. It is also useful to engage with the community to determine their wants and needs. Agencies can use public feedback to guide countermeasure selection and then justify the final selection with data-driven analysis.
• Multiple potential alternatives: It is desirable to identify and develop multiple potential countermeasures for comparison. This helps to identify the most effective and efficient option. It may be useful to develop a flow chart or decision matrix to assist practitioners in selecting appropriate countermeasures or mitigation strategies.
• Cost-effectiveness: Ideally, agencies would select a countermeasure that is highly effective at reducing the focus crash-type. Agencies should also consider construction and maintenance costs because more effective countermeasures (e.g., increasing clearance heights and widths) are often associated with higher costs.

the approximate cost, effectiveness, service life, and other considerations, such as where to use them and, where applicable, potential enhancements. The section concludes with a discussion of data quality improvements that can support a wide range of decisions, including the identification of high-priority locations, diagnosis of risk and crash contributing factors, selection of appropriate countermeasures, and evaluation of past investments.

Passive Systems: The purpose of these countermeasures is to improve driver awareness of bridge and tunnel restrictions through warning signs and enhanced delineation. Additional passive mitigation measures are provided to reduce crash severity. Height warning signing shows the clearance of the bridge or tunnel; sometimes these signs flash. Signing information is almost always 3 inches less than actual clearance, but this can vary from state to state. Inconsistencies among states may lead to inconsistent driver behaviors (e.g., states that give a larger margin of error may lead to drivers taking more risk in their decision to try to pass under the bridge). There is an opportunity to standardize this practice nationally to improve driver expectancy and behavior, especially when hauling across state lines. The following countermeasures are categorized as passive systems:

• Advance warning signs and markings.
• Horizontal alignment warning signs.
• Changeable message signs (CMS).
• Flashing LEDs within signs.
• Bridge and tunnel fascia treatments.
• Hanging chains, strips, bells, or bars.
• Enhanced lateral clearance.
• Enhanced tunnel lighting.
• Enhanced bridge and underpass lighting.
• Transverse rumble strips.
• High-friction surface treatments (HFST).

Sacrificial Systems: The purpose of these countermeasures is to reduce structural damage to bridges and tunnels through impact-absorbing systems installed on the face of the structure.

Advance Warning Signs and Markings

Description

Low-clearance advance warning signs (W12-2) are required for “vertical clearances less than 14 feet 6 inches, or vertical clearances less than 12 inches above the statutory maximum vehicle height, whichever is greater” (MUTCD 2023). When required, clearance height shall be posted in advance of the structure. In addition, a low-clearance overhead sign (W12-2a or W12-2b) may be installed on the structure to supplement the advance warning sign (Figure 23 and Figure 24). Advance warning signs may include low-clearance warnings, specific clearance heights, and other relevant information to warn drivers of an upcoming low-clearance or narrow bridge or tunnel structure. Advance signing could also include directional components (e.g., truck detour or exit) to guide OHVs to another roadway.

Where to Use

Consider advance warning signs for use on all bridge and tunnel approaches based on engineering judgment, even when not required or recommended by the Manual on Uniform Traffic Control Devices (MUTCD). Advance warning signs should be located at a sufficient distance before the bridge to allow drivers to detour, turn around, or stop. Refer to Section 2C.25 of the

More Information

The relevant provisions are contained in Section 2C.25 of the 11th edition of the MUTCD (https://mutcd.fhwa.dot.gov/pdfs/11th_Edition/Chapter2c.pdf) (MUTCD 2023).

Horizontal Alignment Warning Signs

Description

Advance horizontal alignment “warning signs warn drivers that the horizontal road alignment is changing ahead, which may require speed reduction and careful attention. In-curve warning signs (such as chevrons) delineate the outside edge of the road on curves and reinforce the intended path of travel” (MUTCD 2023). Bridges and tunnels with curves on or within the structure or on the approaches may benefit from advance horizontal alignment warning signs.

Where to Use

Agencies can consider multiple advance horizontal alignment warning signs and the chevron alignment signs (W1-8) shown in Figure 25, on any road, bridge, or tunnel where horizontal curves are not readily expected or visible for drivers, or where there is already a history of roadway departure crashes (MUTCD 2023). The MUTCD either recommends or requires devices to indicate a change in horizontal alignment depending on the roadway type and traffic volume. The selection of devices, such as curve warning signs, is based on the speed differential between the advisory speed for the horizontal curve and the posted speed limit, statutory speed limit, or the 85th percentile speed on the approach to the curve (MUTCD 2023). Refer to MUTCD (2023) Table 2C-4B and Table 2C-6 in Section 2C for specific provisions on sign selection and the use of an advisory speed plaque based on the estimated speed differential. Note that consistency in messaging across similar sites is critical for establishing driver expectancy and promoting effective roadway operations (VTrans 2023).

Safety Effectiveness

Chevrons reduce nighttime crashes on curves by 25% [CMF (Crash Modification Factor) Clearinghouse ID 2438 (Srinivasan et al. 2009a)] and nonintersection fatal and injury crashes by 16% [CMF Clearinghouse ID 2439 (Srinivasan et al. 2009b)].

Enhancements

Agencies can consider the following conspicuity enhancements to horizontal alignment warning signs at bridges and tunnels. VTrans notes these conspicuity enhancements “are intended for implementation with an incremental approach based on local site conditions, funding, and engineering judgment” (VTrans 2023).

• A one-direction large arrow sign (Figure 25, W1-6) may be used either as a supplement or alternative to chevron alignment signs or delineators in order to delineate a change in horizontal alignment.
• For safety improvements on curves with existing warning signs, consider oversize and/or doubled-up (i.e., signs on both sides of the road) advance warning signs. Refer to MUTCD Table 2C-2 for conventional and oversize sign dimensions (MUTCD 2023).
• Retroreflective strips (same color as the sign background color) on signposts can be added to existing or new signs when the desired effect is not achieved.
• Fluorescent yellow reflective sheeting can improve conspicuity, particularly in areas with frequent fog or shadows.
• Flashing beacons can help draw attention to signs but should be used sparingly because drivers may tend to ignore devices that are overused.

Costs and Service Life

FHWA’s Countermeasure Service Life Guide estimates a service life of 15 years for horizontal alignment warning signs (Himes et al. 2021). VTrans notes that “agencies should monitor the retroreflectivity of the signs and regular washing is recommended to maintain reflectiveness” (VTrans 2023).

Static signs are relatively low cost, starting around $500 per sign.

More Information

“Enhanced Delineation for Horizontal Curves” (FHWA, n.d.-b).

Changeable Message Signs

Description

CMSs—also called variable message signs, digital message signs, matrix signs, or variable message boards—are digital traffic control devices capable of relaying short messages to drivers (Figure 26). They are often installed upstream of low-clearance structures in conjunction with additional warning devices. Low-clearance bridges and tunnels are defined here as having a vertical clearance of 14.5 feet or less at the lowest point.

Where to Use

Consider overhead or roadside CMS installations for low-clearance or narrow bridge and tunnel structures based on engineering judgment. Messaging should follow applicable MUTCD provisions. Agencies can consider the following factors when assessing the potential use of CMS systems:

• Power source: Permanent CMS system installations require power, which may be wired to direct connections or solar powered depending on the manufacturer.
• Flexibility: Unlike static signs, CMS systems can be programmed to display additional information as needed, such as AMBER alerts, emergency Homeland Security messages, transportation-related messages, or other safety-related information.

Safety Effectiveness

CMS systems are estimated to be 10% to 20% effective in reducing BrTS incidents.

Enhancements

CMS systems are often used in conjunction with active systems, such as early warning detection systems that estimate the height of approaching vehicles and provide real-time feedback for drivers using CMS or other methods.

Costs and Service Life

FHWA’s Countermeasure Service Life Guide estimates a typical service life of 10 years for a CMS (Himes et al. 2021).

Costs depend on the power source, mounting type/location, and length of need for underground conduits. As a starting point, CMS installations may cost around $45,000 per sign.

More Information

Manual on Uniform Traffic Control Devices (MUTCD 2023).

Flashing LEDs Within Signs

Description

Flashing LEDs within signs consist of intermittent lights surrounding or embedded in a sign to increase the conspicuity of the sign. These are considered a conspicuity enhancement and may be most beneficial under nighttime operation (Figure 27).

Where to Use

This conspicuity enhancement can be used with any warning signs (e.g., horizontal alignment warnings, low clearance, or narrow structure warnings), particularly under nighttime operations. Illumination and flashing rates should follow MUTCD Chapter 2A provisions (MUTCD 2023). Agencies can consider the following factors when assessing the potential use of flashing signs:

• Power source: Permanent installations require power, which may be wired to direct connections or solar depending on the manufacturer.
• Mounting location: Signs may be mounted overhead or on a roadside post. Flashing LEDs are installed as part of the sign.

Safety Effectiveness

Research is not yet available for applications of flashing signs/beacons as BrTS countermeasures.

Enhancements

None applicable at this time for this system.

Costs and Service Life

FHWA’s Countermeasure Service Life Guide estimates flashing warning signs have a service life of approximately 10 years (Himes et al. 2021).

Costs depend on the power source, mounting type/location, and length of need for underground conduits. As a starting point, flashing signs may cost around $15,000 per sign.

More Information

Low-Cost Treatments for Horizontal Curve Safety 2016, Chapter 4 (Albin et al. 2016).

Bridge and Tunnel Fascia Treatments

Description

Bridge and tunnel fascia treatments provide high-visibility delineation on the face of the lowest structural elements to visually reinforce low clearances. They are generally continuous installations of retroreflective material across the entire structure (Figure 28). As they are located on the structure itself, they are used as a supplemental countermeasure in conjunction with advance low-clearance warning signs. Bridge and fascia treatments are not a substitute for MUTCD signage.

Where to Use

Consider bridge and tunnel fascia treatments at all such structures based on engineering judgment.

Safety Effectiveness

Research is not yet available for applications of bridge and tunnel fascia treatments as BrTS countermeasures.

Enhancements

Agencies can consider the following enhancements to fascia treatments:

• Advance warning signs, flashing beacons, CMS systems, or other messaging devices; and
• Transverse rumble strips.

Costs and Service Life

Painted fascia treatments are generally low cost at around $20 per linear foot and are expected to have a service life of 20 to 25 years; however, cost and service life will vary depending on materials, humidity, and length of need. Regular maintenance is recommended to maintain reflectivity and visibility.

More Information

“Bridge Strike Mitigation” (NYC 2009).

Hanging Chains, Strips, Bells, or Bars

Description

Hanging metal chains, strips, bells, or bars, also known as telltale signs, provide auditory feedback upstream of the bridge or tunnel to warn drivers if their vehicle height exceeds the minimum vertical clearance provided at the structure. These systems consist primarily of an overhead structure with chains, strips, bells, or bars that hang down and terminate at the minimum clearance height for the bridge or tunnel structure downstream (Figure 29). OHVs strike the system and receive loud feedback while the corresponding signing warns them of the likely BrTS collision ahead.

Where to Use

Consider this countermeasure upstream of low-clearance bridge and tunnel structures based on traffic speeds, traffic volumes, OHV BrTS crash history, and engineering judgment. Low-clearance bridges and tunnels are defined here as having a vertical clearance of 14.5 feet or less at the lowest point. Agencies should consider the following factors when assessing the potential use of hanging chains, strips, bells, or bars:

• Traffic speeds: Ambient noise tends to increase as vehicle speeds increase, which in turn diminishes the feedback provided by this countermeasure. Installations perform best when

Where to Use

Consider increasing lateral clearance to bridge and tunnel walls/barriers at horizontal curves or locations with a history of roadway departure crashes. Enhanced lateral clearance to walls/barriers can provide recovery space for drivers who leave the travel land and therefore may reduce roadway departures crashes.

Safety Effectiveness

Narrow shoulders and proximity to barriers promote slower speeds but may increase the potential for barrier strikes. Research has shown that bridge width should include at least 3 feet of shoulder on both sides of the road or at least one-half the shoulder widths on approach roadways, whichever is greater. One study estimated the crash rate increases by approximately 60% if the total shoulder width drops from 6 feet (i.e., the desirable minimum) to 3 feet; in contrast, increasing the total shoulder width from 6 feet to 9 feet decreases the estimated crash rate by approximately 42% (Mak 1987).

Enhancements

None applicable at this time for this system.

Costs and Service Life

FHWA’s Countermeasure Service Life Guide estimates bridge widening has a service life of 30 years (Himes et al. 2021). Costs can vary significantly based on bridge type, estimated increase in bridge width, and site-specific design parameters.

More Information

Mitigation Strategies for Design Exceptions, Chapter 3 (Stein and Neuman 2007).

Enhanced Tunnel Lighting

Description

Crashes near tunnel entrances and exits tend to be more severe than crashes along the interior zones, and abrupt changes in lighting may be a contributing factor. Lighting transitions from light to dark conditions are especially difficult for older drivers as this aspect of vision tends to degrade over time.

Enhanced tunnel lighting targets two components—the roadway and the walls (Figure 31). Tunnel lighting may be improved by implementing zonal lighting and differing daytime and

High-Friction Surface Treatments

Description

HFST are pavement treatments that can reduce crashes associated with friction demand issues. This includes a reduction in pavement friction during wet conditions as well as high-friction demands due to vehicle speed or roadway geometric design. HFST involves the application of very high-quality aggregate to the pavement using polymer binders to restore or maintain pavement friction in needed areas.

Where to Use

HFST can address issues in areas where vehicles may brake excessively and/or where pavement surfaces may become prematurely polished such as

• Sharp horizontal curves,
• High-volume intersection approaches,
• Interchange ramps, and
• Bridges.

Safety Effectiveness

HFST has been demonstrated nationally and internationally to provide significant increases in friction for spot applications. FHWA’s “Proven Safety Countermeasures” website reports the following reductions for HFST applications (FHWA, n.d.-f):

• Sixty-three percent for injury crashes at ramps (Merritt et al. 2020).
• Forty-eight percent for injury crashes at horizontal curves (Merritt et al. 2020).
• Twenty percent for total crashes at intersections (Harkey et al. 2008).

Enhancements

A possible enhancement to HFST would be a drainage study to identify contributing factors for high incidences of wet-weather crashes.

Costs and Service Life

State DOTs report HFST costs ranging from $25 to $50 per square yard (FHWA, n.d.-d). HFSTs are highly durable, and treatments have an expected life cycle of approximately 10 years. While the initial cost is high, the life cycle makes HFST a feasible investment, especially compared to geometric improvements to areas with high numbers of crashes. A recent study from South Carolina DOT indicates the benefit-cost ratio has proven HFST to be a very cost-effective countermeasure (FHWA, n.d.-c).

More Information

Several case studies detail real-world HFST applications available via the FHWA’s “Case Studies and Noteworthy Practices” resource page, including applications of HFST in California, Florida, Georgia, Iowa, Kentucky, New York, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, and Washington (FHWA, n.d.-a.).

Sacrificial Systems

The purpose of these countermeasures is to reduce structural damage to bridges and tunnels through impact-absorbing systems installed on the face or in front of the structure. The following countermeasures are categorized as sacrificial systems:

1. Crash beams and portal frames and
2. Energy-dissipative system.

Crash Beams and Portal Frames

Description

Crash beams and portal frames absorb some of the impact energy just before OHVs collide with structures. Crash beams and portal frames primarily protect infrastructure and may have a negative impact from a safety standpoint for road users in the vicinity of the crash. Their design and capabilities vary by manufacturer, and there are tradeoffs between the strength of the beam and the ability of the beam to dissipate energy without damaging the bridge structure.

Crash beams may be comprised of steel plates, I-beams, or a combination of both, and are generally attached to the face of a bridge or similar structure. Portal frames are the same as crash beams, except they are installed as a separate structure in front of the bridge and absorb impact independently from the structural members of the bridge (Figure 34). If an OHV collides with a crash beam or portal frame, the beam will deform to a certain extent to absorb some of the impact, and it will also cause damage to the vehicle. These effects are exacerbated as vehicle speeds increase. Most importantly, crash beams and portal frames do not prevent structural deformation of the bridge or tunnel structure; rather, they serve to limit the resulting damage to the structure by absorbing some of the impact energy before the vehicle collides with the main structure. Limiting structural damage to the bridge or tunnel may, in turn, decrease the rehabilitation costs and duration.

Where to Use

Crash beams and portal frames are commonly used at low-clearance railroad bridges (a vertical clearance of 14.5 feet or less at the lowest point) on low-speed roads. Crash beams and portal frames may cause substantial damage to the OHV that impacts the beam, which in turn may cause debris from the OHV or the beam to be scattered onto the road, roadside, or nearby vehicles. Careful consideration of safety impacts is recommended before selecting crash beams or portal frames as a countermeasure, and they should not be installed on high-speed roads.

Safety Effectiveness

The sacrificial system is estimated to be 30% to 50% effective in reducing BrTS incidents (Cawley 2002). Research is ongoing regarding the safety impacts of crash beams and portal

Where to Use

Energy-dissipative systems are typically located on the bottom portion of exterior girders of bridges. This includes energy-absorbing materials such as aluminum honeycomb. For limited access facilities, this type of treatment would generally apply to the first bridge in the series from each entry point.

Safety Effectiveness

An energy-dissipative system acts as a reactive sacrificial system in the case of BrTS to mitigate the damage to both the bridge and commercial vehicle. This countermeasure is in the prototype and development phase.

Costs and Service Life

The system may need to be replaced after each BrTS incident, so service life depends on the number of BrTS occurring post-installation. Costs vary as the prototype is under construction. Depending on the features desired and areas covered, there may be multiple vendors that can meet an agency’s needs. Agencies are encouraged to conduct due diligence in evaluating the options available.

Active Systems

The purpose of these countermeasures is to improve driver awareness of bridges and tunnels through detection- or location-based warning systems. The following countermeasures are categorized as active systems:

1. Routing systems.
2. Early warning detection systems.
3. Smart Roadside commercial motor vehicle monitoring.
4. License plate camera recognition system.
5. Structure monitoring systems.

Routing Systems

Description

Routing systems for oversize vehicles are designed to improve safety and protect infrastructure. Agencies often use these systems to issue permits more efficiently and to ensure an accurate and reliable route (Figure 36).

Where to Use

Routing systems are used when planning a route and issuing a permit.

Agencies can consider the following factors when assessing the potential use of routing systems:

• Features desired.
• Maintenance of underlining data.
• Technical support.
• Data storage.
• Expandability.
• Interface and communication features.
• Security of input data/hauler information.
• Virus protection.
• Cost.

Safety Effectiveness

Accurate routing systems can minimize human error in route planning, thereby improving the efficiency and effectiveness of this countermeasure. Accurate and reliable routing and permit issuance may be the single most effective countermeasure to mitigate BrTS, assuming the hauler follows the approved route.

Enhancements

Haulers may have difficulty understanding information or restrictions from the different systems used by different authorities. Standardization, such as the following, would be valuable:

• Standardize the routing system used by all jurisdictions within a state.
• Standardize the routing system used by all states.

Costs and Service Life

Costs vary by software provider and the features included with OHVs being just one area. The software needs to be maintained and kept current with restrictions that develop or are eliminated. Depending on the features desired and the area covered, there may be multiple vendors that can meet an agency’s needs. Conduct due diligence in evaluating the options available.

Early Warning Detection Systems

Description

Early warning detection systems or OHVD systems are often installed upstream of low-clearance bridge or tunnel structures (a vertical clearance of 14.5 feet or less at the lowest point) at a sufficient distance for heavy vehicles to stop or exit the road before collision with the structure (Figure 37). Most systems consist of a transmitter on one side of the road (e.g., laser, infrared lights) and a receiver on the other; between these two elements, a beam of light or similar spans the roadway at a specified height and relays a notification to a connected system if the beam is broken by an OHV passing through it. The systems may also trigger video recordings of the incident or notify emergency response personnel. Driver feedback occurs immediately, and associated warning signs, beacons, or otherwise provide real-time notifications that encourage the driver to stop. The warning sign may flash yellow beacons and may or may not include an alarm (parabolic shielded bell, electronic siren, horn, etc.) to alert the driver. Variable message signs may also be used to instruct the driver to stop on the side or take some exit prior to reaching the structure. These systems typically can detect speeds up to 75 mph and are typically installed 1,000 feet before the structure to provide sufficient stopping distances. This type of system is already in use in the United States, UK, Germany, Australia, and Canada. Some systems use other light sources such as visible, red, or infrared light as well as modulation schemes to provide improved performance. Additionally, one OHVD system usually covers multiple traffic lanes

Camera.

Some systems may use a single calibrated or multiple video camera system to gauge and prevent OHV strikes through an early warning detection system. This typically features a camera mounted on the side of the road at the height of the low-clearance bridge or object. Camera angle calibration is determined using a reference object and may allow other features of the roadway or vehicle to be captured in the event of or in preventing a strike, such as the height of the vehicle, number plate of the vehicle, and a record of the vehicle at the scene. Cameras face certain limitations in inclement weather, including rain or fog or at night (if OS/OW vehicles are allowed to operate within that state or municipality at night), and lighting around the bridge must be adequate. A camera-based solution may be cheaper than a laser or infrared light warning system or transmitter. Efforts to introduce camera-based systems have been undertaken, including in Cambridge, England.

Smart Roadside Commercial Motor Vehicle Monitoring

Description

Smart roadside commercial motor vehicle monitoring systems feature a variety of technologies that enable the scanning of commercial vehicles (Figure 40). Smart roadside systems measure and record a vehicle’s height, length, and width; can photograph and scan a vehicle’s license plate; potentially produce a three-dimensional (3D) model of the vehicle; scan and record the vehicle’s axle count, spacings, and potential load; determine the vehicle type and classification; and verify the vehicle against a valid issue permit for accuracy and compliance. Different vendors may include some or all of these features and are generally able to record this information while the commercial vehicle is in motion. Technologies incorporated into these monitoring systems may include LiDAR scanners, cameras, and cloud databases. Eye-safe cameras or other sensors (including LiDAR or infrared) that can scan an object—in this case, a commercial motor vehicle—multiple times per second, enabling fully automated length, width, and height measurement with the vehicle speed and movement direction. Software suites may also include the ability

Safety Effectiveness

ALPRs are primarily used for enforcement and compliance with registration, vehicle size, vehicle weight, and operational requirements. These cameras allow an agency to monitor damage caused by heavy vehicles on roadways and ensure commercial motor vehicle compliance. Technical challenges include accuracy and reliability issues with both equipment and databases, especially on older models of equipment, and maintenance. Most use of ALPRs is reactive (Zmud et al. 2021).

Costs and Service Life

The cost of a single ALPR camera can be up to $20,000, not including installation, fiber optics, and other soft costs (Eberline 2008).

More Information

More widespread use of license plate camera recognition systems includes the ability to monitor traffic flow, flag unpaid license and registration vehicles, monitor insurance compliance, and explore other transportation policies/solutions, such as congestion charges, tolls, and high-occupancy travel lanes.

Structure Monitoring Systems

Description

Structure monitoring systems, as illustrated in Figure 42, continuously monitor infrastructure and infrastructure health, including bridges and tunnels. Advanced structural monitoring methods allow for the early detection of possible structural deterioration with the goal of extending the lifespan of structures. These systems monitor the structure and are capable of recording strike incidents and transmitting warning messages to authorities to inspect, or if needed, shut

Some services can collect driver safety information from a variety of sources. Agencies can coordinate with providers and their partners to disseminate safety and restrictive notifications as needed, such as when a major storm is approaching. Some services also partner with major data collection agencies to provide real-time notifications regarding traffic congestion, work zone presence, and a variety of other safety-related travel measures.

Commercial drivers actively using these services can receive push notifications to their mobile device when they are within a geofenced area that has an alert set up, such as for a low bridge. The geofence is large enough to provide the driver adequate time to make decisions before reaching the low bridge. The service provides low-structure alerts for clearance heights (e.g., 14.5 feet or lower).

Where to Use

Consult with service providers to ensure coverage is available in your area.

Safety Effectiveness

Research is not yet available for these services as a BrTS countermeasure.

Enhancements

Some services provide additional information such as infrastructure (parking, rest stops, etc.) and other notifications (weather alerts) as part of a paid subscription. Consult service representatives for more information.

Costs and Service Life

Subscription-based services typically operate as a monthly subscription service. At the time of this publication, the cost for some basic packages was under $20 per month and included safety notifications for low-clearance structures. Low-clearance bridges and tunnels are typically defined as having a vertical clearance of 14.5 feet or less at the lowest point, but this may vary by the service provider. Service life is indefinite, depending on the company’s continuation of services.

Raised Dump Body Light-and-Sound Warning System

Description

Dump body safety devices warn heavy dump truck drivers when there is a problem with their dumper (Figure 45). A dump body is a metallic body whose upper part is generally open and intended for transporting bulk materials. This safety equipment uses both an audible warning device and a warning light to let the driver know when the bucket is still raised while the truck is moving. When a dump body is raised, this can exceed the normal traveling height of the vehicle and may result in a bridge or overhead object collision.

Where to Use

Most dump body safety devices feature a light-up display and audible warning device located within the cab of the truck. Certain models may not activate until the truck reaches a certain speed and are meant for vehicles that move at reduced speeds during unloading to limit inconveniences for the driver.

Safety Effectiveness

These systems act as a preventive safety measure on specific types of commercial vehicles only.

Enhancements

Some models include options for limiting that alarm at low speeds, other speed adjustments, and additional warning inputs. Vendor models vary including different intensities of alarm noise, light flashing frequency, and outside temperatures that the raised dump body systems can withstand. There is an opportunity to consider national vehicle standards for raised dump body warnings.

Costs and Service Life

While exact service life may vary, many vendors supply models with a 2-year warranty. The unit costs around $100, not including installation costs and maintenance.

Truck-Mounted Systems to Monitor Vehicle Load

Description

Truck load monitoring systems may monitor information on a commercial vehicle, including the total vehicle load or axle load or the vehicle’s height (Figure 46) and any changes to the load.

Where to Use

While sensor components of this system must be mounted on the vehicle, such as on the vehicle’s body, trailer, or on top of a truck, these systems generally include an in-cab warning system to alert the driver about shifting vehicle loads or low-clearance hazards.

Safety Effectiveness

Some models may include an aerodynamic sealed sensor unit capable of measuring the height of an overhead hazard and sending a read-out to the in-cab unit to alert the driver. Others may include a dash video insert that will measure and detect the height of the vehicle even as the load changes. Some systems are geofenced and may only operate in certain states based on integrated bridge and other low-height clearance restriction data. Most systems generally include an audible alarm to alert the driver to any excess axle load or low-clearance hazard. Some modern systems may use two cameras together to increase depth perception.

Enhancements

Certain truck-mounted, vehicle load monitoring systems may include a telematics unit or GPS tracker to communicate information to an online fleet management software or the driver’s smartphone.

Costs and Service Life

Camera-based technology with a software suite generally costs from around $500 to $1,000 and may more, depending on installation costs (Maghiar, Jackson, and Maldonado 2017).

Nonphysical Countermeasures

The purpose of these countermeasures is to improve driver awareness of bridges and tunnels through institutional policies, permitting procedures, and driver education programs. The following countermeasures are categorized as nonphysical countermeasures:

1. OHV and axle load restrictions.
2. OHV permits.
3. Vehicle checklists.
4. In-cab height placard.
5. Route surveys.
6. Pilot car/escort vehicle policies.
7. Route atlas (Motor Carriers’ Road Atlas, Truckers Atlas).
8. Commercial navigation system policies.
9. Training and CDL certification.
10. Post-training/certification driver education and outreach programs.

OHV and Axle Load Restrictions

Description

There are several options for posting signs to restrict vehicles. A “Passenger Vehicles Only” sign restricts any commercial vehicles, including delivery or single-unit trucks. “No Truck” regulatory signs are posted at the beginning of the ramps that lead into the roadway section (Figure 47). Axle load restrictions generally refer to weight limits based on distance between axles for bridge formula calculations. Axle spacing is typically measured from the center of the axle to the center of the axle between the outermost wheel or group of wheels.

Where to Use

Agencies can consider the following factors when assessing the potential use of OHV and axle load restrictions:

• Limited commercial businesses on that corridor.
• Operational efficiency or congestion relief.
• Load rating of structures in the corridor.
• Pavement construction and design.

Unintended consequences can include increased truck traffic on parallel or adjacent roads and difficultly for trucks and delivery vehicles to access certain businesses and destinations.

Safety Effectiveness

Truck restrictions can mitigate BrTS by limiting the size and weight of trucks allowed on certain roads and bridges. This can help deter trucks that are too tall or too heavy to safely pass under or over bridges and tunnels. The effectiveness is dependent on driver compliance, which may require supplemental enforcement. There is limited research on the safety effectiveness of vehicle restrictions. Truck lane restrictions can reduce the number of rear-end collisions involving trucks in mixed traffic settings. Truck lane restrictions and vehicle restrictions along certain corridors can also improve traffic flow.

Enhancements

Periods of increased enforcement may be necessary to deter trucks on a posted corridor. In addition, education and outreach are appropriate if there are changes to the allowed traffic on a corridor.

Costs and Service Life

The total cost of posting a truck restriction on a highway will vary depending on the length of the highway segment, the type of restriction implemented, and the level of enforcement. Enforcement and monitoring may be necessary, which can increase the cost associated with signing alone. Costs of truck restrictions can be significant to motor carriers (e.g., increased travel time, routing decisions, hours of service, potential litigation). Agencies should consider all costs before implementing such a restriction.

More Information

For more information on truck lane restrictions, agencies can refer to individual state statutes. There are multiple restrictions on the use of policy to restrict traffic.

OHV Permits

Description

A permit authorizes the movement of an OS/OW vehicle for a specific time period on permissible hauling days. An authority (e.g., state, city, county, town, village) may require a permit for vehicles or loads that exceed legal dimensions in their laws (Figure 48). Applications are required and the permit issued will identify restrictions and an approved route.

Where to Use

Agencies may consider the following factors when assessing the current or potential use of policies and procedures for OHV permits:

• Simple and timely application process.
• Resources and tools needed to issue permits.
• Application and permit fees.

Table 13. Example of state permit fees.

More Information

Most states, cities, counties, towns, and authorities have a permit policy and procedure in place. Information is typically available through the jurisdiction’s website, and most are processed online.

Vehicle Checklists

Description

Checklists increase driver awareness of vehicle constraints, cargo securements, and driver preparedness. Checklists can be created for pre-, mid-, and post-trip completion. Checklists should include measuring the height and width of trucks as well as engine and cab inspection. Figure 49 and Figure 50 show examples of vehicle checklists.

Where to Use

Agencies should consider the following factors when assessing the potential use of vehicle checklists:

• Height measurement training: Drivers often incorrectly measure vehicle and cargo heights, so relevant and ongoing training is critical for reducing BrTS incidents.
• Cargo inspection: Cargo can shift during transit, and drivers should be aware of and react to possible changes in their maximum load height throughout the trip.
• Complacency: As with any repetitive task, drivers may become less attentive over time to standardized checklists. Checklists should be kept to a manageable length to reduce the potential for complacency.

Safety Effectiveness

Research is not yet available on the safety effectiveness of vehicle checklists as a BrTS countermeasure.

Enhancements

Agencies can consider the following enhancements for vehicle checklists:

• Update in-cab height placards at the start of each trip.
• Require drivers to report their maximum load height and other key checklist items to the managing organization before a trip commences.
• Provide drivers with instructions and tools or equipment to measure load height more accurately (e.g., technologies to create a 3D model of the truck) to reduce common mistakes in measuring load height.

Costs and Service Life

Vehicle checklists can be developed by an individual or managing organization with minimal labor hours. Personnel executing the checklists must spend time before, during, and/or after the trip on the task, which may impact trip scheduling and hours of service.

Service life is variable; checklists can be continually updated as the vehicle fleet, driver needs, and cargo makeup change, or due to anything that may impact the serviceability of vehicles, safety of driving personnel, or safety of other roadway users.

In-Cab Height Placard

Description

An in-cab height placard is an adjustable message board that displays the total height of the truck for referencing at low-clearance warning signs. This is especially beneficial when the driver is unfamiliar with the vehicle, such as with box truck rentals or for commercial drivers with inconsistent vehicle/cargo assignments. An in-cab height placard can be as simple as a piece of paper with the total height of the vehicle/cargo written on it. As long as it is within the field of view of the driver (in a way that does not obstruct their view of the road), drivers will not have to memorize the height and can reference it as needed when they see low-clearance warning signs.

Where to Use

Commercial motor carriers, box truck rental companies, RV rental and sales companies, and any other large-vehicle distributors and drivers can benefit from using in-cab height placards. Vehicle height must be accurately measured and confirmed each time any changes are made to the cargo or vehicle. Height measurements may require special tools or training depending on the vehicle/load configuration.

Safety Effectiveness

Research is not yet available for applications of in-cab height placards as BrTS countermeasures.

Enhancements

None applicable at this time for this system.

Costs and Service Life

Material costs and service life are generally negligible for this countermeasure. Height placards should be updated any time modifications are made to cargo or vehicles.

Route Surveys

Description

A common requirement for permitting oversize vehicles is the completion of a route survey. Route surveyors are trained to drive with specific constraints in mind related to the intended transport. They can identify low-clearance bridges (a vertical clearance of 14.5 feet or less at the lowest point), narrow roadways, railroad crossings, low-hanging electrical wires, overhead obstructions, difficult road geometry, and other impediments that may obstruct the intended route based on the load and vehicle characteristics. Route surveyors often use a height pole attached to the vehicle to verify vertical clearance at bridge and tunnel structures. Route surveyors also work with the trucking company and local authorities to identify alternative viable routes where needed. Performing a route survey identifies problems before the route commences, improving the chances for a successful trip and directly reducing the likelihood of BrTS incidents.

Where to Use

Route surveys are commonly required by law for oversize vehicles, but they are also beneficial for any heavy vehicles driving on public roads. Some commercial motor carriers perform route surveys before establishing a new, repetitive route.

Safety Effectiveness

Safety is prioritized over the shortest route, so selected routes may involve increased distances and roads with lower operating speeds. Research is not yet available for the safety effectiveness of route surveys as BrTS countermeasures.

Enhancements

Technology, such as dashboard cameras and voice recorders, may improve route surveys.

Costs and Service Life

There is a fixed cost associated with training the route surveyor. Variable costs include the time and fuel to complete the task. The variable costs will depend on the length of the route and the time to complete the survey. Route surveys should be performed close to the commencement of the trip and updated periodically; communicating with local jurisdictions can help identify work zones, pavement overlays, and any other planned changes along the identified route.

More Information

Pilot/Escort Vehicle Operators: Training Manual (Hamilton 2017).

Pilot Car/Escort Vehicle Policies

Description

Oversized vehicles are commonly required to travel with a leading and/or trailing pilot car/escort vehicle operator (P/EVO) (Figure 51). P/EVOs are used to warn road users of a potential oncoming hazard and to guide large vehicles through or around downstream obstacles that may impede travel. P/EVOs are commonly outfitted with signs, flags, warning lights, and other equipment depending on the governing agency. High visibility is critical for a successful transport. Through constant communication with the driver of an oversize vehicle, P/EVOs can help with stopping and turning maneuvers and communicate downstream travel constraints via CB radio or otherwise.

Where to Use

In many states, oversize vehicles are unable to travel on public roads without an accompanying P/EVO. Laws vary regarding the number of P/EVOs required and minimum thresholds (e.g., vehicle and cargo dimensions and gross weight) that trigger the need for a P/EVO. Many states require cross-coordination among several agencies for a successful oversize-vehicle permit and transport process.

Safety Effectiveness

Research is not yet directly available for applications of P/EVOs as BrTS countermeasures.

Enhancements

Defensive driving courses can improve P/EVO training programs. While P/EVO training courses already exist, they are not required in all states. One opportunity is to require this training and certification in all states with a mandatory refresher every 3 years to remain certified. Another opportunity is to require the use of commercial navigation systems for P/EVO certification (refer to Commercial Navigation System Policies section for further discussion on commercial navigation systems). Vehicle selection for both P/EVOs and heavy vehicles is also increasingly important as new suites of sensors for collision mitigation become available, including side view assist, forward collision warning/mitigation, lane departure warning/mitigation, and electronic stability control, among others.

Costs and Service Life

There are fixed costs and variable costs associated with P/EVOs. P/EVOs are generally required to be trained and/or certified for the task, so there is a fixed cost associated with their training. Some jurisdictions require state-specific vehicle permits; amber light permits; and/or insurance in the form of automotive liability, general liability, and/or professional errors and emissions policies. The variable costs include the time and fuel to complete the task at hand. The variable costs will depend on the length of the route and the time to complete the trip.

More Information

Pilot/Escort Vehicle Operators: Best Practices Guidelines (Hamilton and Owens 2017).

Road Atlas

Description

A road atlas displays low-clearance bridges (a vertical clearance of 14.5 feet or less at the lowest point) on any highway or local road for drivers to reference (Figure 52). Drivers can use a road atlas in conjunction with other navigation software.

Where to Use

An atlas should not be used while driving. Drivers and carriers can use an atlas when

• Engaged in planning and selecting a route,
• Stopped en route to verify or confirm a route, and
• Diverted from a route for emergencies resulting in road closures or diversions or for any other reason.

An atlas is also useful in areas with no cellular or internet service.

Safety Effectiveness

Lack of route planning by haulers has been determined to be one of the leading causes of BrTS (Agrawal, Xu, and Chen 2011; Martin and Mitchel 2004). An atlas is a cost-effective tool to plan routes, particularly for small or occasional carriers.

Enhancements

Atlas publishers could offer digital updates on a regular basis to atlas purchasers.

Costs and Service Life

Atlases are available for purchase online from retailers and publishers as well as in bookstores. They range in price from $15 to $60. While atlases are updated annually, older atlases will include most low-clearance bridges, as low-clearance bridges tend to be older.

More Information

An online atlas is more likely to be current. A printed atlas may not have the most current information and should be used in conjunction with other countermeasures.

Commercial Navigation System Policies

Description

GPS-based navigation systems used by the general driving population do not provide low-clearance warning notifications for bridge or tunnel structures. Commercial navigation applications have this information built in, and they can be programmed to automatically avoid problematic routes and provide audible warnings when approaching low-clearance structures. These specialized commercial navigation applications may reduce BrTS incidents when their use is encouraged and/or required and enforced by motor carriers, law enforcement, and policymakers.

Where to Use

Agencies may consider the following factors when assessing the potential use of commercial navigation system policies:

• Functionality: Key functionality of commercial navigation systems includes GPS-based (not cellular), regular and free software updates, visual and audible warnings, large screen size, customizable based on vehicle height, mounting options, lane assist, and turn-by-turn guidance.
• Source of vertical clearance information: The reliability of these systems is often dependent on the timeliness and accuracy of data from transportation agencies. There is a need for transportation agencies to maintain and provide access to a timely and reliable database of low-clearance structures that is integrable with major commercial navigation.
• Collaboration with manufacturers: Ensuring the devices are gathering information from the correct sources will improve the effectiveness of commercial navigation system policies. There is also a need for the manufacturers to push updates to the devices and for drivers to check for updates regularly to confirm the system is relaying the most recent information.

Safety Effectiveness

NYSDOT estimated that more than 90% of truck drivers were following automobile GPS guidance (i.e., not using a commercial navigation system with horizontal and vertical clearance data) at the time of a bridge strike on parkways (Agrawal, Xu, and Chen 2011).

Enhancements

Some commercial navigation systems provide additional safety-related information beyond vertical clearance data. This could be required for P/EVO certification. Consult individual GPS manufacturers for more information on available services.

Beyond the provision of vertical clearance data for permanent structures, there is an opportunity for transportation agencies to post temporary or recent changes on 511 (e.g., short-term, construction-related activities that affect vertical clearance). Further, there is an opportunity for commercial navigation systems to consume and provide this data to users.

Costs and Service Life

One source suggests an average cost of $200 to $900 per device, depending on desired features, plus a possible nominal monthly fee (Elgin 2023). Service life depends on the selected manufacturer. Base data sources and navigation systems must be updated regularly to capture new information.

Training and CDL Certification

Description

CDL training and certification improve truck drivers’ knowledge about driving larger vehicles, including the associated risks and opportunities to mitigate those risks. It is estimated that a high number of crashes are caused by human factors, including failure to use safety belts, driving too fast for conditions, inadequate surveillance of the roadway environment and failure to notice potential hazards, driver fatigue, driver distraction, following too closely, and inadequate evasive action to prevent collisions.

Drivers hauling cargo can benefit from load securement training to help prevent damage to the infrastructure and cargo and understand DOT regulations. Many load securement or cargo control training offerings include aiding drivers in understanding and assessing various aspects of load securement. For example, for load securement systems involving chains, drivers should understand the working load limit or rated capacity of the chain or sling components as well as the minimum breaking force as tested and verified by the manufacturer of the chain or sling components. Training also covers other aspects of load securement, including relevant regulations, inspection intervals, required securement points based on load dimensions, and securement strategies/types of tie-downs. Common cargo securement violations include failing to secure vehicle equipment, failing to load vehicles to prevent load shifts, insufficient tie-downs, loose or unfastened tie-downs, and damage to securement systems or tie-downs.

Where to Use

This is mandatory for all commercial truck drivers.

Safety Effectiveness

Regular cargo and tie-down inspection intervals are required for compliance with regulations as well as to enhance safety. For example, it is recommended that drivers inspect their cargo before the vehicle is taken on the road, within the first 50 miles of any trip, and then at regular intervals based on whichever occurs first: every 150 miles, every 3 hours of driving, or each duty status change. Regular inspection can prevent load shift issues by allowing drivers to detect movement or shifting of a load before it becomes a safety hazard.

Enhancements

In the aviation industry, training has proven highly effective for commercial pilots. Training is done using a standardized curriculum and meeting training requirements outlined in 14 CFR Part 135 and 142. This standardization has aided in the effectiveness of training as all carriers are required to meet the same standards and provide the same training at the same frequency to all pilots. Standardized curricula are created for specific aircraft types and include applicable regulations, resources for maintaining training syllabi, differences in training types (initial hires, initial equipment, transitions, upgrades, recurrent, adaptive recurrent, or requalification) as well as recommended topics covered and sample checklists to utilize during training. This standardization would benefit motor carriers looking to improve their driver training programs and training effectiveness; it would also ensure that all motor carriers’ employees are operating with the same skill sets throughout the nation.

Costs and Service Life

Costs and training frequency requirements vary.

Post-Training/Certification Driver Education and Outreach Programs

Description

Driver education and outreach programs may benefit both professional trucking industries and nonprofessional drivers (e.g., those with passenger vehicle licenses operating rented or purchased large vehicles). Examples of education and outreach may include newsletters, seminars, coordination with driving schools, inclusion of a section related to BrTS in CDL testing, outreach with carrier organizations and independent operators, websites, annual safety courses, or any combination. Possible education or outreach programs may include the following:

• For professional truck drivers: This may include routine refresher courses on measuring vehicle and cargo height, selecting routes appropriate for their vehicle height, and ensuring commercial GPS systems with low-clearance structure warnings are used.
• For nonprofessional drivers: This may include coordination with local moving truck rental companies, RV retailers, and motor vehicle licensing offices to improve awareness of vehicle heights and roadway restrictions. Drivers may be unaware that truck prohibitions and low-clearance warnings apply to them, as formal education on this subject is often not provided upon issuance of driver licenses for passenger vehicles or when renting a vehicle.

One challenge to driver education is the diversity of the trucking industry where carriers range in size from large companies with more than 1,000 drivers to single-person owner-operators. Another challenge is bad operators (e.g., chameleon carriers that change the company name after being put out of business). It is generally difficult to change the behavior of these operators who intentionally violate rules and regulations.

Where to Use

Agencies can consider the following factors when assessing the potential use of driver education and outreach programs:

• Crash history: Consider targeting outreach and education programs to the appropriate offending driver population, based on whether BrTS incidents are occurring due to professional truck drivers or nonprofessional drivers in similarly large vehicles. Further investigation may reveal patterns in BrTS incidents to narrow the target audience for education and outreach programs, such as whether these incidents are more often related to fleet operators or independent operators.
• Trucking industry needs: Consider a collaborative approach with trucking industry leaders to establish viable truck routes and standardized procedures for avoiding low-clearance structures.

Safety Effectiveness

Research is not yet directly available for applications of post-training/certification driver education and outreach programs as BrTS countermeasures.

Enhancements

Agencies can consider the following enhancements to driver education and outreach programs:

• In-cab height placards: This may be particularly beneficial for nonprofessional drivers renting or purchasing vehicles when a formal training program is not required to operate the vehicle.
• Enforcement of truck prohibitions through fines or other techniques: This may improve adherence to truck restriction policies and subsequently reduce BrTS incidents. This may require coordination with law enforcement and policymakers in adjacent states or jurisdictions as well as tribal community representatives.
• Newsletters or similar: Photographs of bridge hits, congestion caused by bridge hits, and associated statistics may be beneficial, particularly if this information is distributed in response to permit requests.
• Consider requiring periodic (e.g., annual) refresher courses to promote continuous awareness of the associated social and economic costs of BrTS events and how to prevent them.

Costs and Service Life

Costs and service life vary depending on the agency offering certifications, frequency of staff turnover for personnel receiving training, and frequency of refresher courses.

Other Tried Strategies

In addition to the extensive list of countermeasures in the previous sections, transportation agencies and local governments have tried other strategies to prevent or mitigate BrTS. The following are select examples of these strategies:

1. Lane reduction.
2. Ramp closure.
3. Increased fines and enforcement.

Lane Reduction

If there are multiple lanes under a bridge or in a tunnel, there is an opportunity to reduce the number of lanes. A lane reduction intends to shift the travel path of vehicles to the location where there is the greatest clearance height and avoid areas under the bridge where there is low clearance. Other benefits of lane reduction can include reduced travel speeds, increased driver awareness of warning signs, and added shoulder width for pedestrian or bicycle facilities.

Example Application: In June 2023, the NYSDOT implemented this strategy on the four-lane Route 370 (Onondaga Lake Parkway) for a distance of 1,200 feet on each side of the CSX railroad bridge, which is intended to calm traffic and give OHVs additional time to heed the warning signs and avoid the bridge. The lane restrictions are being evaluated for their effectiveness and their impact on traffic conditions.

Ramp Closure

Ramp closures could involve complete closure to all vehicles or partial closures that prohibit certain vehicles from using specific ramps. The intent is to prevent larger vehicles from accessing roads with low-clearance bridges or tunnels.

Example Application: The NYSDOT implemented this strategy by closing a I-81 northbound ramp to State Highway 370 (Onondaga Lake Parkway) to eliminate trucks from directly accessing the parkway. The ramp closure is being evaluated to assess the impact and effectiveness of the lane reduction on the parkway.

Increased Fines and Enforcement

Local governments can increase fines for unpermitted and overweight vehicles as well as increase enforcement to support local laws. This strategy does not apply to transportation agencies, only to local communities and governments.

Example Application: In combination with lane reduction and ramp closure, the Village of Liverpool, New York, in January 2024, began enforcing its expanded truck ban, first with warnings and then with hefty fines. In the summer of 2023, the village board approved an expanded ban on trucks and tractor-trailers weighing over 5 tons from traveling through the village. The ban is designed to reduce truck traffic on Onondaga Lake Parkway as a further measure to prevent tall vehicles from hitting the famously low CSX railroad bridge. The enforcement began with signs informing drivers of the ban, a 1-week grace period, and then enforcement. The four-figure fines—ranging from $1,200 to $4,700—increase based on vehicle weight. An exception is made for local deliveries. The ban was formally introduced to motor carriers by a certified letter from the village and had to be approved by Onondaga County and the towns of Salina and Clay. While truck traffic from I-81 has been reduced with the ramp closure, which prevented many strikes, trucks from Liverpool still hit the bridge.

Data Quality Improvements

The purpose of this strategy is to improve the quality (completeness, accuracy, and accessibility) of data used to inform decisions, including the OHV permitting process. For instance, without accurate data on structure size, roadway conditions, and load size, the permitting process will not provide an optimal route. In some states, these data are collected but not easily accessible by motor carriers and those involved in the permitting process. In other cases, these data become stale over time. For instance, a 3-inch overlay causes a 3-inch reduction in vertical clearance that should be updated and reflected in the data. Transportation agencies can support this initiative by providing complete, up-to-date, and accessible inventory data for structure size and roadway conditions. Motor carriers and drivers can support this initiative by providing accurate data on the load size. There is an opportunity to leverage the use of burgeoning data exchanges to share and broadcast updated information, including information on the location of work zones and related restrictions.

As discussed in Section 2.5, there are opportunities to improve the quality of data related to BrTS crashes. Specifically, law enforcement and transportation agencies can move toward electronic crash reporting and adopt the suggested data fields in MMUCC to improve uniformity and consistency for identifying BrTS from the crash data. Further, agencies can consider installing cameras or other technology at high-risk locations to better capture the true number of BrTS crashes. Refer to Section 2.5 for further discussion on collecting, integrating, and disseminating relevant data to investigate and mitigate BrTS crashes.