An object detection and camera system for heavy equipment can prevent work zone struck-by injuries by alerting operators of their surroundings.
Hazard Analysis — Work Zone Struck-by Injuries and Fatalities
Problem:Workers that construct and refurbish concrete and asphalt roadways may face hazards from work zone struck-by injuries and fatalities.
Workers performing highway construction and maintenance may be at risk of work zone struck-by injuries. The lack or improper use of safety equipment or warning devices can lead to these struck-by injuries or fatalities.
Work zone struck-by injuries and fatalities may involve workers with non-construction passenger traffic or construction heavy equipment. Two of the main contributing factors that increase these struck-by risks is worker visibility and lighting.
Operators using heavy equipment also have blind spots that may cause struck-by accidents. Heavy equipment operators will usually have an obstructed field of view in which they may not see surrounding workers in the rear when operating the equipment. Back up incidences, or "backovers," can result in fatalities and non-fatal injuries such as as amputations, compound and simple fractures and crushing injuries.
The lack of, or improper, illumination during nighttime highway construction and maintenance can also affect worker visibility. Because of higher daytime traffic flow, shifting construction work to nighttime can present other unique risk factors as well that include: drivers being drowsy and less alert, higher incidences of impaired drivers, higher traffic speeds.
Level of Risk:
The National Highway Traffic Safety Adminstration (NHTSA) reported that the U.S. in 2010, 576 of the 32,885 vehicle crashes that involved fatalities (1.8%) occured in construction work zones (NHTSA 2010).
In perspective, ninety-nine of the 279 construction site deaths (35%) that involved vehicles and heavy equipment happened in traffic work zones for highway, street, and bridge construction in 2005 (NAICS 2373). These traffic work zones had twice the percentage of deaths among workers on foot compared to other construction sites. In more than 71% of the traffic zone deaths, the workers were struck by vehicles working in the zone or passing vehicles that entered the work zone. At other construction sites, 39% struck by vehicles, 34% of the on-foot workers killed were struck by vehicle loads.
CPWR The Construction Charts Book: The U.S. Construction Industry and its Workers. 4th edition. December 2007.
Fatality Analysis Reporting System (Fars) 2010 ARF, The National Highway Traffic Safety Administration (NHTSA)
Assessment for work zone hazards should be an integral part of the site safety planning process.
To assess the likelihood of struck-by accidents, here is a list of general items to consider when performing tasks with construction work zones near equipment / traffic:
- Are workers wearing the proper reflective personal protective equipment (Class I, II or III)?
- Are traffic control devices (TCDs), flaggers and lighting in place where needed?
- If available, are workers behind protective barriers?
- Around equipment, are workers aware of potential "blind spots"?
- Around equipment, can workers communicate effectively with operators?
- Are spotters available if a worker must work with their back to equipment or in operator blind spots?
- Do workers understand the traffic control plan?
Regulations & Standards:
OSHA standard 29 CFR 1926.601(b)(4), under Motor Vehicle, states that "no employer shall use any motor vehicle equipment having an obstructed view to the rear unless i) the vehicle has a reverse signal alarm audible above the surrounding noise level or; ii) the vehicle is backed up only when an observer signals that it is safe to do so."
OSHA standard 29 CFR 1926.602(a)(9)(ii) states that "no employer shall permit earthmoving or compacting equipment which has an obstructed view to the rear to be used in reverse gear unless the equipment has in operation a reverse signal alarm distinguishable from the surrounding noise level or an employee signals that it is safe to do so."
OSHA standard 29 CFR 1926.952(a)(3), under Mechanical equipment, states that "no employer shall use any motor vehicle equipment having an obstructed view to the rear unless i) the vehicle has a reverse signal alarm audible above the surrounding noise level or; ii) the vehicle is backed up only when an observer signals that it is safe to do so."
The US Department of Transportation, Federal Highway Adminstration 23 CFR 630 Subpart J. Work Zone Safety and Mobility Rule encourages broader consideration of the safety and mobility impacts of work zones across project development and the implementation of strategies that help manage these impacts during project delivery.
ANSI/ISEA 107 requires material testing of high visibility safety apparel and headwear by an independent, accredited test lab. Manufacturer attestation or independent, accredited test lab attestation for final configuration.
ANSI/ISEA 207 requires material testing of high visibility public safety vests by an independent, accredited test lab. Manufacturer attestation or independent, accredited test lab attestation for final configuration.
ANSI/ASSE A10.47-2009 Work Zone Safety for Highway Construction provides guidelines that cover workers engaged in construction, utility work, maintenance, or repair activities on any area of a highway.
Federal OSHA Standards are enforced by the U.S. Department of Labor in 26 states. There are currently 22 states and jurisdictions operating complete State plans (covering both the private sector and state and local government employees) and 5 - Connecticut, Illinois, New Jersey, New York and the Virgin Islands - which cover public employees only. If you are working in one of those states or jurisdictions you should ensure that you are complying with their requirements.
The US Department of Transportation, Federal Highway Adminstration defines standard traffic control devices necessary for trafic safety. Manual on Uniform Traffic Control Devices http://mutcd.fhwa.dot.gov/
OSHA work zone safety quick card: http://www.osha.gov/OshDoc/data_Hurricane_Facts/work_zone_safety.pdf
Self-adjusting and directional backup alarms are an engineering control that can limit noise exposure. These alarms are designed to focus the noise to a certain area or only be slightly louder than the ambient noise in the vicinity of the vehicle. By focusing the noise created by the alarm, only those who are directly behind the vehicle will hear it. By automatically adjusting the sound level of the alarm to be as low as possible, while still loud enough to be heard by workers near the vehicle, pedestrians, neighbors and bystanders will not be exposed to unnecessary noise from construction vehicles. Using these alarms is also a safe work practice which can also serve as warning indicators to prevent work zone struck-by accidents by heavy equipment.
Temporary longitudinal barriers are designed to create positive barriers between motorists in roadway traffic and construction work areas. These barriers redirect vehicles in a smooth and stable manner without causing rollover while limiting their intrusion into the work zones.
BIM is a concept that offers software application to integrate building information for hazard identification and safety planning.
Temporary traffic control devices (TTCD) provide for the reasonably safe and effective movement of road users through work zones; protect workers performing the many varied tasks within the work space, as well as road users and equipment; and improve mobility by minimizing congestion and community impact.