In the 1980s TV show Hills Street Blues, Sergeant Phil Esterhaus would tell his officers at the end of roll call, “All right, that’s it, let’s roll. And Hey!… let’s be careful out there.” It was a popular “catch phrase” in those days and certainly can be applied equally well today. Especially in light of recent events, which should not be taken lightly. Considering this a little differently, it should be the motto for every worker on a construction jobsite, especially those on road and bridge crews.
Those work zones are characterized by traffic pattern changes, narrowed rights-of-way, the presence of construction equipment, and work vehicles frequently entering and leaving construction areas. This combination of factors presents challenges for crews and passenger and commercial vehicles driving in and around work zones. Challenges that are not always met successfully as fatality reports show.
The leading causes of death in the road and bridge construction sector are run overs, back overs, and falls, with many of these fatalities due to vehicle intrusion. Simply put, drivers, passengers, and field workers are all at risk.
The FHWA (Federal Highway Admin.) has numerous efforts under its Work Zone Management Program to mitigate the safety and mobility impacts of work zones. FHWA’s Work Zone Management Program supports transportation practitioners through a comprehensive set of innovative strategies and tools, including ITS (intelligent transportation systems) technologies, improved data collection, training grants, and resources tailored to the commercial trucking industry and state and local agencies. These tools and programs help with planning, designing, and implementing safer, more efficient, and less congested work zones.
In 2015, FHWA launched the SWZ (Smarter Work Zones) initiative to help agencies better design, plan, coordinate, and operate work zones. SWZ includes two strategies: (1) project coordination to harmonize construction projects to reduce work zone impacts, and (2) technology applications, such as queue management and speed management systems, to dynamically control traffic in and around work zones.
Smarter Work Zones: Technology Applications
Agencies can use a variety of ITS applications to enhance work zone mobility and safety.
- Realtime traveler information systems provide drivers with realtime travel conditions prior to and within a work zone and may also provide information on alternative routes in the corridor. The goal is to divert drivers away from the work zone when congestion exists.
- Queue warning systems quickly detect the presence of congestion at the work zone and warn approaching motorists that traffic is slowed or stopped ahead.
- Dynamic lane merge systems encourage motorists to merge at specific points as they approach a lane closure, depending on current operating conditions.
- Incident management systems enable agencies, contractors, and responders to detect incidents in the work zone faster, allowing quicker response and clearance.
- Variable speed limit systems harmonize speeds before and within the work zone, calming traffic flow and warning of slowed or stopped traffic ahead.
- Automated enforcement systems detect and capture images of speeding vehicles for enforcement purposes.
- Entering/exiting vehicle notification warns drivers of slow-moving construction vehicles that may be entering the travel lane. It can also warn travelers that a work vehicle is exiting the travel lane and not to follow it into the workspace.
- Performance measurement systems monitor and archive data on traffic conditions to support real-time traveler information dissemination, modify operations, and facilitate evaluation.
Work zones may be synchronized with other work zones within a corridor, network, or region, and possibly across agency jurisdictions, to minimize combined impacts to travelers and to produce time and cost savings. Early identification of potential impacts enables agencies to improve the coordination of construction activities, resulting in a greater ability to reduce and manage traffic disruptions from road work, minimizing traveler delay and maximizing road work efficiency. ITS technologies support the dynamic management of work zones and provide actionable information to drivers and traffic managers. As a result, drivers can make more informed decisions leading to reduced congestion and improved safety.
But technology and planning can only go so far. Public awareness of the dangers in construction zones is also needed. The ATSSA (American Traffic Safety Services Assn.), representing the roadway safety infrastructure industry, is one of the organizations that is working toward that end.
In 1997, a group of VDOT (Virginia Dept. of Transportation) staff members wanted to dedicate a week to raise awareness about work zone safety among all district employees before construction projects picked up during the warmer months. Following the successful promotion of this first event, VDOT brought the idea of raising awareness to other DOTs, and, in 1999, the Caltrans (California Dept. of Transportation) began its statewide public awareness campaign, “Slow for the Cone Zone.”
Also in 1999, ATSSA approached the FHWA and the AASHTO (American Assn. of State Highway Transportation Officials) to launch the first official NWZAW (National Work Zone Awareness Week). The goals were to:
- Initiate efforts to raise awareness of the need for more caution when driving through work zones to decrease fatalities and injuries
- Establish and promote a uniform set of safety tips
- The value of training and importance of best practices in regard to work zone safety would be promoted among individuals in the private sector, industry, and roadway workers
- Reach out to both roadway workers and contractors to communicate possible effects of motorists’ behavior in response to traffic delays, and advise on what steps might possibly be taken to lessen negative behavior
In addition, outreach efforts would be made to work with entities involved with work zone safety and to form partnerships. One result was National Go Orange Day, designated to help raise work zone safety awareness. The event is a time for individuals and organizations across the country to express their support for work zone safety by wearing orange. It celebrated its seventh year on Wednesday, April 13, 2022.
Various states have implemented programs for work zone awareness, both by drivers and crews. The statistics show that both are responsible for safety in the zone. In addition to the risk of injury from passing motor vehicle traffic from outside the work zone, there is an equally hazardous risk of injury from movement of construction vehicles and equipment within the work zone.
In analyzing the data collected on fatalities and serious nonfatal injuries occurring from 1992-1998, NIOSH (National Institute for Occupational Safety and Health) researchers concluded that “safety efforts must also protect construction workers within work zones who are working on foot around moving vehicles and equipment. Collision incidents are attributed in part to limited visibility around the equipment.” Indeed, struck-by incidents are a leading cause of death among construction workers, and since 1992 the leading cause of nonfatal injuries in the construction industry.
For example, hydraulic excavators are used in road construction to move large quantities of earth. An excavator quick coupling device (quick coupler) can save a lot of time on the jobsite by allowing the rapid change of buckets and other attachments on the end of excavator dipper arms.
Depending on the design, they may be used to connect attachments remotely from the cab or may require the operator to complete the connection of the device manually on the ground by inserting a locking pin. Safety mechanisms are built into most modern quick couplers, but they are not fail-proof. But when an excavator bucket unintentionally detaches from a quick coupler, worker fatalities can—and have—occurred.
Excavators are dangerous to work around. The boom and dipper arm move quickly in small spaces such as a trench and carry extremely heavy loads. An excavator bucket can weigh 900 pounds while empty, and significantly more when holding soil or rock, making a failure very dangerous.
Three deaths have been reported since 2019 as a result of a worker being crushed by a bucket that fell from a quick coupler. While quick couplers have their own individual safety specifications, it is important to note employers must ensure their workers are never working beneath a bucket, attachment, or load and that workers should never be within the swing.
Some recommendations to prevent injuries or fatalities from excavators with quick coupler devices:
- First and foremost, maintain work practices and administrative procedures to keep workers away from an elevated load and out of the swing radius of both the excavator dipper arm and the excavator superstructure.
- Ensure a training program has been implemented for operators who use quick couplers.
- Always ensure the quick coupler is properly engaged by using approved safety checks, visual indicators, and/or warning devices. If required by the manufacturer, the safety locking pin must be in place prior to lifting the attachment off the ground.
- Prior to using an attachment, always perform a connection test as specified by the manufacturer.
- Adhere to regular maintenance of the quick coupler device according to manufacturer guidelines.
- If a quick coupler or an attachment needs to be inspected, do not approach the device unless the attachment is lowered and resting on the ground. This is equally important for manually attached quick couplers that require a worker to secure the attachment or manually place a manufacturer-specified safety locking pin.
- Use only manufacturer-approved and compatible attachments.
- Install retrofit safety kits on older quick coupler devices or upgrade to newer quick couplers with built-in safety mechanisms. Human detection systems may also be available in some newer excavators to prevent contact with a worker who is within the swing radius.
The number of fatalities occurring in work zones has increased from 546 in 2010 to 842 in 2019 (the latest year for full statistics). During the same 10-year period, injuries in work zones have gone from 36,000 in 2010 to 39,000 in 2019, but have varied significantly from year to year. In addition:
- Approximately four out of every five work zone fatalities in 2019 involved a driver or passenger of a vehicle
- On average, more than two persons per day were killed in work zones in 2019
- Based on the CRSS estimates, a traffic crash occurred in a work zone every 5 minutes during 2019
States have devised various programs to mitigate these numbers and some have been adopted by other states, indicating their acceptance and success. To ensure the safety of both motorists and highway construction and maintenance workers, New York State’s efforts to raise awareness about Work Zone Safety include the obvious, requiring motorists to slow down, be alert, and drive carefully in all work zones.
In addition, motorists are required to move over a lane if safely possible for vehicles along the road displaying red, white, blue, amber, or green lights. This includes emergency response vehicles, tow trucks, and highway construction and maintenance vehicles. Failure to comply will result in significant civil and possible criminal penalties.
The reason for emphasizing work zone safety in New York can be seen in the state’s number: in 2018, there were 701 crashes in work zones on state roads and bridges, resulting in 13 motorist fatalities and 329 injuries to motorists, contractor employees, and NYSDOT staff.
Arizona DOT Equipment Services tries to adjust flash patterns on vehicle lighting systems to avoid critical flash frequency ranges that may be associated with “hypnotic” or seizure effects.
Traffic Group vehicles use a combination of stationary, rotating, and oscillating halogen lights on most trucks to provide appropriate lighting for varying situations. This provides excellent results in terms of day/night visibility and durability.
ADOT is now using more and more LED-based lighting equipment, but still uses halogen lights for rotating beacons. In ADOT’s experience, focused halogen reflector lamps (rotating, stationary, or oscillating) provide superior visibility compared to any other existing lighting technology under difficult or challenging ambient light conditions such as dawn/dusk backlighting, extremely bright sunlight, etc.
Although halogens still make up the ‘backbone’ of ADOT’s lighting equipment, LEDs are being used more and more often where appropriate, such as for stationary lamp arrays or high-vibration environments. Although LEDs do not yet equal the combination of intensity and flash duration that halogen lamps provide, LEDs do offer far lower amp draw for comparable brightness and greatly improved vibration resistance.
In 2018, there were 1,804 work zone crashes in Pennsylvania, resulting in 23 fatalities. With increases in distracted driving and continued speeding in work zones, additional safety measures were necessary. Pennsylvania authorized a system of Automated Work Zone Speed Enforcement (AWZSE) using portable systems (either vehicle- or other apparatus-mounted) to detect and record vehicles exceeding work zone posted speed limits by 11 miles per hour or more using electronic speed timing devices (radar or nonradar).
Some states turn to the state university system for research and suggestions. In Texas, traffic studies are performed by the Texas A&M Transportation Institute (TTI). One factor in its latest efforts was the changes in traffic patterns caused by the COVID-19 pandemic and its associated lockdowns and restrictions. The study of the state’s most congested street and highway segments, showed overall delays on states roads was sharply reduced by a pandemic-driven drop in traffic volume and a temporary shift of traffic concentration away from peak “rush hour” periods.
Drivers experienced lower traffic delays on the monitored Texas roadways in 2020 than they did in 2019. More delays also occurred outside typical rush hours than in the previous year, likely due to the increased number of people working from home and school closures.
Delay for trucks was also down, especially during the early days of the shutdown, though truck volumes recovered at a faster rate than passenger vehicles. This is perhaps an indicator of how home and store deliveries were sustained—and in many cases increased—throughout the pandemic.
The sharp drop in delay time on Texas roadways was short-lived, with traffic volume steadily increasing in the fall of 2020, as it did generally throughout the U.S. during the same time. While 2020 was a very unusual year for traffic patterns, it’s important to note congestion jumped back quickly to almost pre-pandemic levels as we have moved through 2021.
National efforts to reduce work zone injuries have resulted in several suggestions being implemented by numerous states. The following recommendations are a sample:
- Use DMS (dynamic message signs) if work will be conducted at night. The presence of the DMS is more effective than static signs at reducing driver speed in the overnight hours. The presence of the sign is not detrimental at other times but is truly beneficial when it is dark on the roadway.
- Use a longer refresh rate between messages on the dynamic message sign. This allows drivers time to read and interpret the information displayed on each screen.
- If workers will be present in a work zone, mention their presence on the dynamic sign. This heightens the awareness of the driver as they approach the work zone.
Previous research and outreach have focused largely on passenger vehicle safety and mobility in work zones. However, the challenges that large trucks and buses must contend with when driving through work zones are different and more complex. Longer stopping distance requirements, larger blind spots, reduced maneuverability due to narrower lanes, and reduced brightness or increased glare during nighttime operations create hazards that can lead to injuries and fatalities.
Every year, large trucks are over-represented in fatal work zone crashes. In 2016, 184 crashes involved large trucks, accounting for more than one-quarter of fatal work zones crashes nationwide. By comparison, only 9% to 12% of fatal crashes outside of work zones involve large trucks each year.
To address this situation, FHWA is partnering with Federal and State government agencies, trucking associations, and other safety stakeholders to conduct a multiyear campaign to improve large truck safety in work zones. The agency has developed and continues to grow its suite of resources, including webinars, brochures, and guidance documents.
Smart and connected work zones are becoming commonplace in North America, supported by integrated IoT (Internet of Things) technology. Consolidating this set of traffic control and roadway infrastructure devices—colloquially known as an IoR (Internet of Road Work)—allows drivers, contractors, traffic managers, and others to receive real-time status information about key traffic control devices being used in roadway construction operations and any disruptive anomalies they may cause to surface transportation.
As with every area of safety, there are technology offerings available for a variety of applications. iCone Products created a cloud-based data service for digitally marked work zone events called the R.O.A.D. Database. The Real Ontime Accurate Data (R. O. A. D.) for Work Zones is a cloud-based database of road event data supplied by preeminent equipment and infrastructure developers, IoT equipment retrofit companies, construction operators, maintenance, and traffic control companies. This database represents an industry-first in that it is populated by the actual producers and generators of the work-zone data, collectively known as the Work-Zone Data Industry.
The R.O.A.D Database will be the clearinghouse for work zone-generated attributes that may require corrective, attentive action, or alertness from roadway users. The launch of the R.O.A.D database will be made possible through relationships with several major traffic control equipment manufacturers, pavement marking companies, and other significant producers of smart work zone technology and data that perform tasks on a daily basis such as temporary work zones, lane closures, protecting lives and equipment, painting lanes, closing roads, and performing maintenance, through automatic communications from devices integrated inside roadway assets.
Studies from the University of Minnesota and other institutions have found digital alerts providing advance warning of upcoming roadway hazards improve driver safety near roadside incidents and can reduce the risk of crashes up to 90%. By notifying motorists of these hazards in advance, digital alerts provide drivers with more time to safely slow down and move over or proceed with caution.
HAAS Alert‘s Safety Cloud, a digital alerting platform for roadway safety, is now incorporated into real-time roadway hazard information in Apple Maps, one of the world’s most widely used mapping, navigation, and traffic solutions. Drivers approaching emergency vehicles, incident responders, work zones, and other hazards on the road sourced by Safety Cloud will receive an alert in Apple Maps, giving them advance warning of a potential safety issue ahead.
More than 1,200 public safety agencies, roadside assistance fleets, towing operators, road workers, and other organizations with vehicles or roadway equipment are using Safety Cloud to provide an additional layer of protection for their people and assets. The service comes standard on new emergency vehicles for many leading industry brands and also integrates with aftermarket emergency vehicles, telematics systems, work zone equipment, and traffic management platforms. More than 1 billion digital alerts have been processed through Safety Cloud since the platform’s launch in 2017.
Intellinium Detection Pod has been identified by U.S. researchers from the University of Alabama as a potential tool to protect and save workers at risks after a work zone intrusion. Technically speaking, a Detection Pod is a highly secured “blackbox” which can detect, notify authorities, and log abnormal events.
Although the device is small in terms of size and weight, it has enough power and telecom capabilities to process AI (artificial intelligence) algorithms and to connect to almost every telecom network available. It is equipped with a large array of sensors that can be used to detect not only impact but also other types of abnormal events. The device is equipped with a small photovoltaic solarpanel that provides extra power autonomy. It can achieve weeks, if not months, of power autonomy.
Some work zone intrusion mitigation technologies suffer from severe shortcomings besides long term power availability. In investigating ways to protect road crews, keep in mind these considerations:
- Reliability: False positive alerts cannot be accepted in work area where workers will not trust a system if an alert occurs without reason.
- Detectability: To a certain extent, the protective system should be able to detect car, trucks, two-wheel (motorcycle and even bicycle), and pedestrian intrusion.
- Size and Weight: Too complicated or too heavy can be a dealbreaker for worker acceptance and use in real life.
- Set-up time: The set-up time on the field should be very short, a couple of minutes, not more than five minutes.
- Mounting / Unmounting: It must be simple and user-friendly and not be error prone.
- Resistance to harsh conditions: Outdoor work areas can be very challenging in terms of temperature (peak and variations), humidity, sun exposure (UV degradation), oil presence or other chemical components, or even an explosive environment.
- Warning coverage: An alarm can only notify workers within a given area and the distance strongly depends on ambient noise, wind, and even worker hearing level.
- Realtime: The warning should be in realtime not only to workers nearby but also to field managers and central monitoring.
- Safety: A safety solution should not be a hazard for road users in case of accidental collision. In case of impact, the equipment shall not represent a hazard for other road users and/or workers nearby.
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