Train Road Signs

RED ARROW—A red arrow means STOP until the green signal or green arrow appears. A turn may not be made against a red arrow.

GREEN—A green light means GO, but you must first let any vehicles, bicycles, or pedestrians remaining in the intersection get through before you move ahead.

GREEN ARROW—A green arrow means GO, but first you must yield to any vehicle, bicycle, or pedestrian still in the intersection. The green arrow pointing right or left allows you to make a protected turn; oncoming vehicles, bicycles, and pedestrians are stopped by a red light as long as the green arrow is lit.

FLASHING YELLOW— What does a flashing yellow light mean? A flashing yellow signal light warns you to be careful. Slow down and be especially alert.

White roadsign

Implementing biosafety and biosecurity in the laboratory can initially present an additional burden to laboratory staff and managers. However, they should not ignore the relevance of applying biosafety principles in the workplace.[1]

Laboratory-associated infections continue to become sources of diseases to the laboratory workforce. This is due to failing to implement fundamental control measures in the laboratory. This stems from the most effective control: "elimination," followed by "substitution," "engineering controls," "administrative," and "personal protective equipment" (eg, respirator use) as the least effective.[2][3]

Knowledge of biohazard levels must not be limited to laboratory professionals. All healthcare workers need to be aware of the categories of biohazard levels because they can impact every patient. For instance, signs and symbols should always be posted on medical floors when dealing with a high-level biohazard.

Rules of the road signs

You can turn left ONLY if you have enough space to complete the turn before any oncoming vehicle, bicycle, or pedestrian becomes a hazard. Vehicles turning left must always yield to those going straight from the opposite direction.

Risk-group classification of required biosafety precautions is ideally a logical approach to minimize laboratory-acquired infections. However, while each laboratory can easily identify and meet the special considerations required, the practicality of the actual day-to-day situation of the laboratory workflow is still more important. Strict adherence to these biohazard levels can benefit some facilities that can comply. In a similar case previously described for TB laboratories, a risk-based approach is more applicable so that safety precautions can be "tailor-fit" to the activities of each clinical laboratory. Further studies are still essential to make this a reality on a global scale.[10][8]

A right turn can be made against a red light ONLY after you stop and yield to pedestrians and vehicles in your path. DO NOT turn if there is a sign posted for NO TURN ON RED.

Biosafety level 3 (BSL-3) includes the control of infectious agents, which can cause both "serious hazards" and a potentially lethal condition to the laboratory and community via the respiratory transmission of the organism. A typical example of an organism under this classification is Mycobacterium tuberculosis, the bacterial agent responsible for tuberculosis. There have been challenges for program and tuberculosis (TB) laboratory managers in implementing the specific considerations for this level, particularly in resource-limited and TB, high-burden settings because there is insufficient biosafety expertise available to conduct individualized risk assessments for TB laboratories. Applying the biosafety level classification in BSL-3 requirements may not practically and adequately match the specific precautions relevant to the laboratories performing TB-related tests and procedures. To solve this problem, TB laboratories adopted a risk-assessment approach instead of applying the concept of BSL-3 (which is a risk-group approach). Any TB laboratory (a clinical, medical, or public health laboratory carrying out TB diagnostic tests) can classify as low risk, moderate risk, or high TB risk based on the amount of aerosol generated during the conduct of a particular laboratory procedure. Countries with TB, still a significant public health concern, have adopted these guidelines.[6][7][8]

Biosafety level 1 (BSL-1) controls microorganisms unusually known to cause disease with "minimal hazards" to the laboratory and the community. A recent study involves the selection of a BSL-1 bacteriophage surrogate to assess the efficacy of a chlorine-based surface disinfectant for Ebola outbreaks. This study recommends the collaboration of BSL-4 and non-BSL-4 facilities to assist in selecting and researching better surrogates, which can be more effective in BSL-4 conditions.[4]

Road Closedsign

YELLOW—A yellow signal light warns you that the red signal is about to appear. When you see the yellow light, you should stop, if you can do so safely. If you can't stop, look out for vehicles that may enter the intersection when the light changes.

TRAFFIC SIGNAL BLACKOUT—If all traffic signal lights are not working because of an electrical power failure, you must stop at the intersection and then proceed when you know other turning and approaching vehicles, bicycles, or pedestrians have stopped. A blacked-out traffic signal works the same as a four-way stop intersection.

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End of the roadsign

FLASHING RED—A flashing red signal light means exactly the same as a stop sign: STOP! After stopping, proceed when safe and observe the right-of-way rules.

Four classifications of biosafety levels (BSLs) exist. Each level contains specific recommendations for a clinical microbiology laboratory focusing on laboratory practices, safety equipment, and facility construction. As each level progresses, it includes additional biosafety considerations from the previous level. For example, BSL-2 has kept the components of BSL-1 with further requirements, and the same applies to BSL-3 (BSL-2 with additional requirements) and BSL-4 (BSL-3 with additional requirements). The complexity of each level aligns with infectivity, disease severity, the microorganisms’ ability for transmission (including exposure routes), and the nature of the laboratory work to be performed.

Regulatory traffic signs

Biosafety level 4 (BSL-4) is the highest and "most complex" biohazard level, involving a relatively few clinical microbiology laboratories. A high transmission via aerosol makes the pathogens more dangerous for the laboratory workforce and the surrounding community. Marburg and Ebola viruses fall into this risk group. Stakeholders and international experts attended European conferences to revisit the issues that emerged for BSL-4 implementation. They seek opportunities to use BSL-4 in public health, diagnostics, and research regarding its sustainability, improvement of existing training designs and curricula, and strong collaboration to address biosafety and biosecurity. An integrated partnership of human, veterinary, and military laboratories with BSL-4 facilities is necessary to unify its approach to developing laboratory biosafety standards. The participation of BSL-4 in outbreaks can be substantial to attain more effective outbreak management.[9]

Pedestrian roadsign

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Do not enter an intersection, even when the light is green, unless there is enough space to cross completely before the light turns red. If heavy traffic causes you to block traffic, you can be cited.

Traffic control signals are devices placed along, beside, or above a roadway to guide, warn, and regulate the flow of traffic, which includes motor vehicles, motorcycles, bicycles, pedestrians, and other road users.

Biosafety level 2 (BSL-2) controls microorganisms generating "moderate hazards" to the laboratory and the community. In other parts of the world, there are still no guidelines for validating and certifying biosafety laboratories[2]. The year 2017 saw the identification and analysis of issues regarding biosafety implementation in BSL-2 and BSL-3. There is a need to make clear distinctions between certification and validation of clinical and microbiological laboratories. The need for careful implementation must be first recognized.[5]

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Biohazard levels, more commonly referred to as “biological safety levels” or “biosafety levels,” are classifications of safety precautions necessary to be applied in the clinical microbiology laboratory depending on specific pathogens handled when performing laboratory procedures. Developed by the Centers for Disease Control and Prevention (CDC), this principle allows medical laboratory scientists and other lab personnel to identify and limit any biological hazards and further reduce the risk in the laboratory. Biohazard levels, on the other hand, also support the principle of biosecurity, which aims at preventing the use of microorganisms as harmful biological agents.