After the publication of the Brazilian standard ABNT NBR 15486:2016, new concepts were introduced in the vertical signaling of Brazilian highways. What was commonly referred to as a signaling plate transformed into a vertical signaling system.
Basically, before the norm’s publication, the most important item was the signaling plate itself, summarizing the importance of vertical signaling in the retroreflectivity of films, while the rest was considered accessory.
The norm established the concept of ‘Forgiving Highways,’ thereby giving relevance to everything related to the infrastructure on the roadside to minimize the effects of an accident involving a vehicle’s impact against a fixed obstacle.
This conceptual shift brought about the vertical signaling system, now considered composed of the reflective film, the substrate for its adhesion, the elements fixing the plate to the support, the support itself, and the necessary foundation to keep the entire system firm and upright.
Signaling became an integral part of passive safety, which, besides meeting the requirements for vertical signaling, also requires compliance with all elements established for it to become a passive safety system, known in Brazil as collapsible.
Being collapsible doesn’t merely entail being destroyed by a vehicle impact but rather meeting a series of engineering requirements established through technical standards and mathematical calculations. This certification gives the product the necessary approval to become a passive safety device.
For a product to be considered part of passive safety, it needs to be tested according to parameters set by European or American technical standards. In the European case, the technical standard is EN 12767, which establishes:
- Speed class => Mandatory: 35 km/h
- o Choose one: 100 km/h – 70 km/h – 50 km/h;
- Predictability;
- Activation mechanism => collapse mode
- THIV and ASI => Theoretical head impact velocity and Acceleration Severity Index;
- VE – Exit Velocity => Energy absorption category;
- Roof sinkage risk;
- Post-impact stability;
- Direction class => Single; double; or multiple;
- Type of foundation, usually specially made for the device.
These aspects are obtained through ‘crashtest’ trials, summarized in a series of numbers and letters representing the trial results.
Let’s analyze an example of a certification with the following result:
100-NE-C-X-SE-MD-0
The number ‘100’ represents the Speed Class the device is designed for, requiring two ‘crashtests’: one at 35 km/h speed (mandatory to confirm collapsibility) and another choosing between speeds of 50 km/h, 70 km/h, or 100 km/h. In this example, the chosen speed is 100 km/h, meaning the product is certified for roads with any speed. If it were 50 km/h, the product could only be used on roads with a maximum speed of up to 50 km/h.
The letters ‘NE’ refer to the kinetic energy absorption resulting from impact, which can be ‘HE’ for high absorption, ‘LE’ for low absorption, or ‘NE’ for no absorption.
The letter ‘C’ indicates the occupant safety level, related to the theoretical head impact velocity. The lower this velocity, the higher the occupant safety level. This level is qualified by letters ‘A’ through ‘E.’ Level ‘C’ is the best for devices undergoing shearing during impact, while level ‘A’ is optimal for devices distorting upon impact.
The ‘X’ relates to the system’s foundation, which can be concrete, soil, or both. If represented by the letter ‘X,’ it indicates that the foundation contributes to collapsibility and is part of the manufacturer’s proprietary calculations.
The abbreviation ‘SE’ demonstrates the device’s collapse mode, either by shearing or deformation. In this example, it’s by shearing.
The letters ‘MD’ indicate the direction class: ‘SD’ for traffic direction with a 20º entry angle, ‘DD’ for both traffic directions with a 20º entry angle, and ‘MD’ for multidirectional impacts, where the impact can occur in any direction and at any entry angle.
Lastly, the number ‘0’ indicates whether there was a depression in the roof upon impact. ‘0’ signifies a depression of up to five centimeters. For depressions larger than ten centimeters, it’s represented by the number ‘1.’ In such cases, a verification will be necessary to identify if the depression might cause injuries to occupants.
Understanding the letters and numbers representing a certification allows one to conclude that a device subjected to ‘crashtest’ trials represents a significant advancement in road safety. It’s not enough to simply accept from a representative that their product is passive safety; it must be demonstrated through a certificate with a ‘CE’ mark, where the annex will detail the test reports. Understanding the meaning of the test summary indicates the safety level the device achieves.
The PNATRANS – National Plan for Reducing Traffic Deaths and Injuries – conceptually establishes that ‘responsibility is shared by those who design, construct, manage, oversee, and use roads and vehicles, and by those responsible for attending to victims.’ This shared responsibility should not be neglected but rather considered of utmost importance by all of us involved in traffic in any capacity. Establishing the obligation to adhere to and use the concepts included in current technical standards is a road safety policy that saves lives.”